The Little Owl: Population Dynamics, Behavior and Management of Athene noctua [2 ed.] 1009100157, 9781009100151

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The Little Owl Population Dynamics, Behavior and Management of Athene noctua Second Edition

The basic biology of owls is poorly understood compared to that of other bird species. The Little Owl, Athene noctua, is one of the best models for biological and conservation research. Though widespread across Europe, Asia and North Africa, populations of the Little Owl are now in decline, making studies of its behavior and ecology all the more important. This extensively revised and updated second edition features substantial new long-term data on population dynamics, behavioral observations and breeding biology of the Little Owl. The authors discuss its wide-ranging ecology, genetics, subspecies and population status by country. In addition, they outline a research strategy and monitoring program. Exceptional illustrations of all 14 subspecies cover embryonic and chick development, feather growth and molt, including high-quality drawings presenting concrete management suggestions. Whilst being an invaluable resource for academic researchers, its accessible and straightforward style will also appeal to amateur ornithologists and enthusiasts. Dries Van Nieuwenhuyse is a life-long owl researcher and statistician active in ecological method development and publication. He is Professor of Performance Management at EHSAL Management School in Brussels and thought leader in fact-based decision-making. He has authored five books on the impact of technology and statistics on the decisionmaking processes of organizations, and in particular brings his skills as a statistician to his ornithological work. Ronald van Harxen is Chairman of the Dutch Little Owl Working Group (STONE), and has been active in the research and conservation of the Little Owl in the Netherlands and internationally for more than 43 years. His research focuses on breeding biology and population dynamics within nestbox populations. He received several awards including the Special Achievement Award in 2016 from the World Owl Hall of Fame, International Owl Center, Houston, USA. David H. Johnson is Executive Director at Global Owl Project, USA. He is currently working on a “12-year demographic study of the Burrowing Owl (Athene cunicularia) 2010–2022.” He has worked in natural resource conservation for 42 years and has written two previous books on owls, wildlife and fisheries.

Published online by Cambridge University Press

Published online by Cambridge University Press

The Little Owl Population Dynamics, Behavior and Management of Athene noctua Second Edition

DRIES VAN NIEUWENHUYSE EHSAL Management School, Brussels, Belgium

RONALD VAN HARXEN Dutch Little Owl Working Group (STONE)

DAVID H. JOHNSON Global Owl Project, USA

ILLUSTRATED BY JORIS DE RAEDT

Published online by Cambridge University Press

Shaftesbury Road, Cambridge CB2 8EA, United Kingdom One Liberty Plaza, 20th Floor, New York, NY 10006, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia 314–321, 3rd Floor, Plot 3, Splendor Forum, Jasola District Centre, New Delhi – 110025, India 103 Penang Road, #05–06/07, Visioncrest Commercial, Singapore 238467 Cambridge University Press is part of Cambridge University Press and Assessment, a department of the University of Cambridge. We share the University’s mission to contribute to society through the pursuit of education, learning and research at the highest international levels of excellence. www.cambridge.org Information on this title: www.cambridge.org/9781009100151 DOI: 10.1017/9781009103725 First edition © D. Van Nieuwenhuyse, J.-C. Génot and D. H. Johnson 2008 Second edition © Dries Van Nieuwenhuyse, Ronald van Harxen, and David H. Johnson 2023 This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press and Assessment. First published 2008 Second edition 2023 Printed in the United Kingdom by TJ Books Limited, Padstow Cornwall A catalogue record for this publication is available from the British Library. Library of Congress Cataloging-in-Publication Data Names: Nieuwenhuyse, Dries van, author. | Harxen, Ronald van, author. | Johnson, David H., author. Title: The little owl : population dynamics, behavior and management of Athene Noctua / Dries van Nieuwenhuyse, EHSAL Management School, Brussels, Belgium, Ronald van Harxen, Dutch Little Owl Working Group (STONE), David H. Johnson, Global Owl Project, USA ; illustrated by Joris De Raedt. Description: Second edition. | Cambridge, United Kingdom ; New York, NY, USA : Cambridge University Press, 2023. | Revised edition of: The little owl : conservation, ecology and behavior of Athene noctua / Dries van Nieuwenhuyse, Jean-Claude Génot, David H. Johnson. 2008. | Includes bibliographical references and index. Identifiers: LCCN 2022056296 (print) | LCCN 2022056297 (ebook) | ISBN 9781009100151 (Hardback) | ISBN 9781009108249 (Paperback) | ISBN 9781009103725 (epub) Subjects: LCSH: Little owl–Conservation. | Little owl–Ecology. | Little owl–Behavior. Classification: LCC QL696.S83 N54 2023 (print) | LCC QL696.S83 (ebook) | DDC 598.9/7– dc23/eng/20221219 LC record available at https://lccn.loc.gov/2022056296 LC ebook record available at https://lccn.loc.gov/2022056297 ISBN 978-1-009-10015-1 Hardback Additional resources for this publication at www.cambridge.org/littleowl Cambridge University Press and Assessment has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication and does not guarantee that any content on such websites is, or will remain, accurate or appropriate.

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Contents

Foreword

ix

Jean-Claude Génot Preface

xi

Acknowledgements

xv

Executive Summary

1

1

Introduction: Framework

5

2

History and Traditions

9

3

Fossil Evidence, Taxonomy and Genetics Chapter Summary 3.1 Fossil Evidence 3.2 Discovery of the Species 3.3 Discovery of the Subspecies 3.4 Morphology and Coloration 3.5 Morphological Descriptions 3.6 Geographical Distribution 3.7 Genetic Approach 3.8 Vocalizations 3.9 Taxonomic Discussions

4

Morphology and Body Characteristics Chapter Summary 4.1 Embryonic Development 4.2 Owlet Development 4.3 Plumage 4.4 Molt 4.5 Eyes 4.6 Ears

20 20 21 22 27 45 48 73 80 87 88

89 89 89 92 101 107 114 118 v

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Contents

4.7 4.8 4.9 4.10 4.11

Bill Measurements Voice Flight Digestive Organs

119 122 131 144 145

5

Distribution, Population Estimates and Trends Chapter Summary 5.1 Distribution 5.2 Population Numbers 5.3 Densities 5.4 Trends 5.5 Overview per Country

146 146 148 152 155 163 168

6

Habitat Chapter Summary 6.1 Natural Habitats 6.2 Anthropogenic Habitats 6.3 Habitat Preferences 6.4 Habitat Suitability Factors 6.5 Assessments at Multiple Spatial Scales 6.6 Multilevel Resource Selection

239 239 240 241 244 250 264 269

7

Diet Chapter Summary 7.1 Hunting 7.2 Capturing Prey 7.3 Prey Caching 7.4 Prey Species 7.5 Large Prey 7.6 Seasonal Variation 7.7 Geographical Variation 7.8 Different Methods

271 271 271 275 276 278 279 279 281 283

8

Breeding Season Chapter Summary 8.1 Pair Formation and Pair Bond 8.2 Life Expectancy 8.3 Copulations 8.4 Nest Sites 8.5 The Nest

324 324 324 327 329 331 337

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Contents

8.6 8.7 8.8 8.9 8.10 8.11 8.12 8.13 8.14 8.15 8.16 8.17 8.18 8.19 8.20 8.21 8.22 8.23

9

10

Eggs Laying of Eggs Laying Interval Clutch Size Replacement Clutches Incubation Hatching Egg Failure Prolonged Incubation Number of Nestlings Nest Success Egg Success Condition Fledging Success Mortality Cainism Lifetime Reproductive Success Extra-Pair Copulation

337 342 344 345 354 356 358 360 363 364 368 371 373 374 380 382 382 385

Behavior Chapter Summary 9.1 Body Movements 9.2 Locomotion 9.3 Roosting and Sleeping 9.4 Preening 9.5 Nest-Site Competitors 9.6 Enemies 9.7 Social Behavior 9.8 Territorial Behavior 9.9 Division of Tasks 9.10 Parents and Young 9.11 Handling Prey 9.12 Two Females Nesting Together 9.13 Behavior Towards Humans

386 386 386 388 388 390 392 395 396 397 398 398 400 403 404

Population Regulation Chapter Summary 10.1 Introduction to Population Regulation 10.2 Environmental Limiting Factors 10.3 Demographic Limiting Factors

405 405 407 407 435

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Contents

11

Management and Conservation Chapter Summary 11.1 Conservation Status and Threats 11.2 Conservation Strategy for the Little Owl

480 480 480 481

12

Research Priorities 12.1 Research Priorities 12.2 Recent Insights 12.3 Research Topics 12.4 Conclusion

553 553 553 555 562

References

563

Index

608

viii Published online by Cambridge University Press

Foreword

When the first edition of the English monograph on the Little Owl was published in 2008, I was one of the authors since I was involved in the study of this owl at the time, which I studied in France from 1984 to 2006. I was very happy to work with Dries and David. A monograph represents an important work of collecting data and information, as well as exchanges with specialists of the species in a large number of countries, reading and writing in order to give the reader the most synthetic view possible on each topic covered. For me, this work was very rewarding because I learned a lot while writing this monograph. Today it is with pleasure that I write this foreword of the only English updated monograph on the Little Owl, published by Cambridge University Press. Since the writing of the first edition, publications devoted to the species have doubled, which made its updating essential. Techniques have advanced in many topics allowing scientific studies to shed new light on the biology and ecology of this very endearing owl. Hence, this monograph includes more data on aspects such as genetics, morphology and biogeography of the different subspecies. The drawings of Joris De Raedt are of beauty and of great precision, especially those which illustrate the taxonomy. I am sure they will make this monograph enjoyable to read for conservationists and scientists alike. The Little Owl saw its numbers collapse in many European countries during the twentieth century and the global causes are identified, linked in particular to agricultural practices which have profoundly modified the habitats of the species. In France, the National Museum of Natural History sounded the alarm in 2018 on the fall in bird populations linked to agricultural areas: 33% decrease in 15 years, the decline having accelerated between 2016 and 2017. Reasons for this decline are related to intensive agriculture and pesticides. However, the species, being more generalist in terms of diet and more eclectic in the choice of its habitat, seems to resist in a certain number of landscapes, even increasing its population locally. The status of the species varies according to the situation of the meta populations. It will be interesting to see what impact global warming will have on this species, native to the Mediterranean basin. The Little Owl is an interesting species because studying it illustrates our ecological footprint and our impact on rural landscapes. It was the emblem of Athena, goddess of wisdom and science among the Greeks, which is why its decline or its maintenance sends back to us the symbolic image of our own “wisdom.”

ix https://doi.org/10.1017/9781009103725.001 Published online by Cambridge University Press

Foreword

This book is the result of a huge amount of work, I hope it will be of use to all owl enthusiasts. It is undoubtedly a reference book on the Little Owl. Many thanks to Dries, Ronald and David for completely revising the first edition and making it an indispensable work. Jean-Claude Génot Ecologist

x https://doi.org/10.1017/9781009103725.001 Published online by Cambridge University Press

Preface

Little Owls have always meant a great deal to me since my childhood. It was one of the first bird species that I learned to know and appreciate. My favorite bird lived in an old pollard willow nearby. More than ever little things are felt to be more important in life than big things. The Covid pandemic showed the relativeness of all things in life and forced us to go back to the basics. This was not an evident period for many people that suffered from illness, lost loved ones or were exposed to extreme stress due to solitude and psychological tension. This negative spiral led to sorrow and intense need for consolation. No wonder that compassionate communities emerged, bringing people and local organizations together at intimate places of consolation to find peace of mind and get back on the road. I dedicate this book to all people, especially youngsters, that had some mental difficulties in this hard period, seeking comfort and balance in life. May this poem offer solace and ease of mind like my Little Owl is still offering to me through each glimpse, each hoot, each facial expression of this wonderful bird with the golden eyes.

Pollard Willow I bury myself with soaking feet in the grooves of my skin I preserve the touches of grandchildren and grandparents sometimes I break out of myself, my sap flows too fast my hollows silence the birds that have chosen me pollarded I show my wounds shamelessly, my growth is curtailed I must germinate once more capture light in my branches find my voice again when the wind contradicts me Steven Van Der Heyden

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Preface

Special thanks to Trui, my wife and Juul and Siel, my children who helped me through tough times when the combination between a family life, a busy stressful job, rebuilding our house and writing a book were extremely energy-consuming. Thanks for the support, the belief that this book would succeed and the comprehension that writing this book simply had to be done. This book is the result of a joint effort of the whole Little Owl community, the multitude of volunteers and Little Owl enthusiasts throughout its distribution range. It was very comforting as author to have access to all those data and insights that were collected over decades with the utmost dedication. Hopefully these volunteers, professionals and not least the professional volunteers enjoy reading this book and realizing that this book would never have been possible without their continuous efforts and willingness to contribute their findings for the greater interest. It was an honor to sense the belief that this book would act as a lever for all their work and dedication. Last but not least I wish to thank Ronald, David and Joris for their remarkable effort in making this book a success. Jean-Claude Génot, who retired to have more time to enjoy playing with his grandchildren nowadays, was so kind to write the Foreword and stimulated to make the update of this volume a real success. This book would never have been possible without our very intense co-operation and the willingness of all of us to deliver a piece of art that the Little Owl deserves. Dries Van Nieuwenhuyse

xii https://doi.org/10.1017/9781009103725.002 Published online by Cambridge University Press

Preface

This book holds plenty of insights that were obtained from the Zuidoost-Achterhoek research area in the Netherlands. This body of knowledge is the result of a unique cooperation with Pascal Stroeken who should be mentioned explicitly. As a team we managed to collect this unique wealth of data and insights that this research has yielded. Without our 35-year-old close friendship and the co-operation between us, this information would never have been collected in this way. The number of hours spent together in the field are innumerable. The same applies to the inspiring exchanges of views on almost all aspects that are discussed in this book. Without Pascal’s meticulous “accounting,” many results – especially in the Breeding chapter – could not have been presented in this way. Ronald van Harxen The Little Owl is truly an international species whose conservation and cultural impacts have reached far beyond its actual distribution. What an honor and wonderful opportunity it has been to work with Dries, Ronald and Joris on this book, and to bring together our collective insights and skill sets about owls. I sincerely appreciate the caring and thoughtful efforts of all of the people that have worked with the Little Owl, sharing their publications and perspectives, assessments and analysis, and amazing societal insights. I would also like to dedicate this book to the members of the Global Owl Project. My life has become richer through our shared communications, explorations, addiction to owls and the friendship I have had with you over the years. It is upon this collective foundation that our book was possible. Thank you so very much. David H. Johnson Seeing my subjects in their natural habitat is often the very first step in the making of my illustrations. Keeping a nature journal with field sketches helps me get familiar with the character of the species and makes it easier to capture its essence in the final illustration. Looking through a spotting scope I make (visual) notes of the animals I’m studying. Travelling was a bit hard during the pandemic, but I was able to observe Little Owls close to home in Belgium, Cyprus (definitively not Athene noctua lilith!) and Spain in the preparation of the book. Luckily, Dries was also able to provide additional pictures of all the subspecies, including study skins. He was even able to get footage of the mysterious spilogastra and somaliensis. As individual differences are often bigger than the differences between subspecies it took lots of research and studying to represent the discriminative plumage of each subspecies. More than any previous assignment I did, the habitat of these plates was very important, visualizing the environment in which the owls thrive. I would like to thank Dries, Ronald and David for their excellent guidance and feedback during the making of the illustrations. I would also like to thank my partner Linde, and my family for their patience and critique. Special thanks to Raf Beyers, Eddie Schild, Niels Schild and Anders Gray for sharing their knowledge.

xiii https://doi.org/10.1017/9781009103725.002 Published online by Cambridge University Press

Preface

Figure P.1 Fieldwork by the artist in Edegem, Belgium.

The illustrations in this book are a combination of graphite sketches and digital illustrations. Color and details are added on the computer using a graphic tablet. To see more on my workflow, visit my website, jorisderaedt.com or follow me on Instagram; @jorisderaedt. Joris De Raedt

xiv https://doi.org/10.1017/9781009103725.002 Published online by Cambridge University Press

Acknowledgements

This book has many mothers and fathers, it shows our global Little Owl community at its best. The idea of this update ermerged during the Nieuwvliet symposium in 2015 that was held at the Belgian–Dutch border. Crossing borders has always been easy for people in the Low Countries due to their very tiny size. This did not prevent their inhabitants from playing a uniting role across Europe and even beyond. Our Dutch language that we share also forces us to speak a broad range of foreign languages, which is also crucial to capture plenty of gray literature and sometimes very valuable insights that never end up in peer-reviewed journals. So it is no surprise that we are endebted to many people, hopefully we are excused for all those that were forgotten in this overview. In the first place we want to thank several thousands of Little Owl enthusiasts that are active in conservation, education, study, data organization and standardization, publication, . . . It is only through this unique co-operation that projects such as Little Owl 2.0 can be successful. A significant part of new insights in this book stems from camera observations ranging from old-fashioned video recordings to online webcams that are followed by armies of volunteers that monitor each movement of breeding Little Owls, leading to unprecedented volumes of data, standardized and digitized, ready for analysis. Special thanks go to the webcam detectives of Beleef de Lente (Vogelbescherming Nederland) Marja Braams, Hansje Hardenberg, Anna Heijblok, Anjo Schouten, Ellen Verheul, Nel van de Vin, Trudy de Wit and Geert Sterringa (co-ordination) who unravelled and digitized hours of behavior that were never seen before. The advantage of a second edition of this volume was the trustworthiness and the unconditional co-operation of crucial multinational and standardized initiatives of Little Owl data collection for ringing, distribution, population numbers and voice recognition. We are highly endebted to Mark Balman (BirdLife International), Dorian Moss (EURING), Verena Keller (EBCC) and Sergi Herrando (EBCC) for putting all recent available data at our disposal for advanced large-scale analysis. We were lucky in our search for updated high-quality data by different simultaneous initiatives that were converging, e.g., Article 12 of the Bird Directive of the European Union (European Environment Agency) yielded detailed distribution data at the 1010 km scale for all EU member states (luckily still including the UK). The European Breeding Bird Atlas (EBBA2) of the European Bird Census Council covered continental Europe up to the Ural at the 5050 km level. More detailed information was obtained by EURING revealing unique dispersion, fecundity and mortality insights. Zooming out to the

xv Published online by Cambridge University Press

Acknowledgements

global range of the species was enabled by the Macaulay Library – The Cornell Lab of Ornithology – at Cornell University that opened Pandora’s Chapter 4, Morphology and Body Characteristics, outside Europe, allowing virtual travel and the opportunity to see the Little Owl in all its diversity and very accurately behind a computer screen. Xenocanto allowed us to use hours of geocoded sound recordings. Geocoded occurrence data for Little Owls were available from the GBIF – Global Biodiversity Information Facility. We believe that by using all the available data from those organizations, we were not only realizing our objectives, but also theirs, i.e., collect, standardize, analyze and dissiminate insights and knowledge of species for the purpose of their long-term conservation. We hope we have made our contribution through the publication of this volume and are very grateful for the trust they had in us. Literature is crucial in such a huge project. We are specially endebted to Alan Sieradzki, Bruce G. Marcot, Al Vrezec, Anna Heijblok, Lex la Crois, Line Holm Andersen, Lars Bo Jacobens, Gianpiero Calvi, Jevgeni Shergalin, Grzegorz Grzywaczewski and Frank Schram for helping us out with a variety of aspects that are related to tracing, collecting, scanning and organizing literature data. Al Vrezec shared his much appreciated views on taxonomic and bibliographic challenges related to Scopoli and Little Owls. We are highly endebted to Irene Pellegrino who was so kind as to make all pictures of Little Owl skins available to us as the raw material for the illustrations. Koen Aeyels was kind enough to help us out with the maps. We are delighted with the poem by Steven Van Der Heyden who also created an English version for this project. The real-life weathered or Corten Steel version of the poem is 170 cm tall and can be enjoyed in Herzele, Flanders. Special thanks to Norbert Lefranc and Martin Grüebler for their advice and support for this second edition and to Alan Sieradzki for going through the final manuscript and turning it into real English. The next steps in the creation of this book were in the hands of the production team at Cambridge University Press. We are grateful for the continuous effort and belief in this project by Megan Keirnan, Aleksandra Serocka and our content manager, Jenny van de Meijden and copy-editor Jo Tyszka alike. Crucial input of Little Owl insights were obtained from Anita van Dooren, Christien Hermsen, Geco Visscher, Henk Wanders, Ruud Leblanc, Philippe Smets, Ricardo Tomé, Simon Birrer, Guido Desmarets, Magnus Robb, Michael Exo, Koen Van den Berghe, Reuven Yosef, Luis Reino, Boris Nikolov, Grzegorz Grzywaczewski, Rottraut Ille, Hubertus Illner and the many volunteers of Natuurpunt Herzele and beyond. We are greatly endebted to the contributing experts from each country: Albania – Taulant Bino; Algeria – Paul Isenmann; Arabian Peninsula – Michael Jennings; Armenia – Karen Aghababyan; Austria – F. Grinschgl, F. Kloibhofer, H. Steiner, H. Wurm, Ille Rottraut, K. Huber, L. Engel-Klien, Lugmair A., Paar J., R. Zink, Stefan J., W. Geringer, W. Pegler; Azerbaijan – Elchin Sultanov; Belgium – Didier Van Gheluwe; Brussels – Jean-Paul Jacob; Bosnia and Herzegovina – Kotrosan Drazen; Bulgaria – Assen Ignatov, Boris Nikolov, Ignatov Assen, Petar Iankov, Stoycho Stoychev; Croatia – Sven Kapelj, Tibor Kopacki, Vesna Tutis, Vlatka Dumbovicmazal; Cyprus – Christina Ieronymidou; Czech Republic – Alexandra Pruchova, Karel Stastny, Libor Opustil,

xvi Published online by Cambridge University Press

Acknowledgements

Martin Dobrý, Martin Šálek; Denmark – Lars Bo Jacobsen, Egon Østergaard, M. B. Grell, Pelle Andersen-Harild, Timme Nyegaard; Egypt – Mohamed Habib; Flanders – Guido Desmarets, Isabelle Binnemans, Philippe Smets; Former USSR – Jevegni Shergalin; France – Dominique Bersuder, Laurent Couzi, Olivier Hameau, Sebastien Dalloyau; Georgia – Alexander Abuladze; Germany – Bettina Gerlach, Christoph Sudfeldt, Doris Siehoff, Hubertus Illner, Kai Gedeon, Michael Joebges; Hungary – Daniel Hamori, Károly Nagy; Italy – Gianpiero Calvi, Marco Mastrorilli; Israel – Reuven Yosef, Yoav Perlman; Jordan – Fares Khoury; Khazakhstan – Askarisa Bekov; Luxembourg – Marc Junio, Mikis Bastian, Patric Lorgé; Moldova – Silvia Ursul; Morocco – Michel Thévenot; Netherlands – Alex De Smet, Pascal Stroeken, SOVON; Pakistan – Filza Ghafoor, Pankaj Koparde; Poland – Grzegorz Grzywaczewski, Ignacy Kitowski, Tomasz Chodkiewicz, Tomasz Wilk; Portugal – Lourecq Luis, Luis Reino, Ricardo Tomé, Rui Lourenço; Serbia – Dimitrije Radisic; Slovakia – Chrenkova Martina, Jozef Ridzoň, Monika Chrenková; Slovenia – Al Vrezec, Tomaž Mihelič; Spain – Blas Molina, Hugo Framis, Juan Carlos Del Moral; Switzerland – Beat Naef-Daenzer, Christian Meisser, Françoise Schmit, Klaus Robin, Paul Schmid, Peter Knaus; Tunisia – Paul Isenmann; Turkey – Ali Kayahan, Kerem Boyla; Ukraine – Andriy-Taras Bashta, Tatiana Kuzmenko; United Kingdom – Gary Clewey, Neil Calbrade BTO, Roy Leigh; Wallonia – Jean-Yves Paquet. This project was unique in its form due to the fact that crowd funding was organized to finance the illustrations. Two centerfolds, 22 unique plates and 32 chapter logos by Joris De Raedt could be sponsored and magnificent gift cards purchased (Figure 8.7). Theo Boudewijn co-ordinated fundraising in the Netherlands, Trui Mortier in Flanders succeeding in a joint effort to close the financial gap. Obviously, we want to specially thank our sponsors for their generous support and belief in this project. Double Plate: Vogelbescherming Nederland, Uilenwerkgroep Waasland. Plate: Anja Menck, Astrid de Roos, Erwin de Visser, Frederik Dierickx, Hein Bloem (International Owl Center, Huston, MN, USA), Jouke Altenburg, STONE Steenuilenoverleg Nederland, Van Der Haegen Dirk BVBA. Chapter Logo: Jules Tolboom, René De Boom, Piet Vanhaverbeke, Peter De Ruytter, Koenraad Bracke, J. Ter Stege, Henk and Wilma Lammers, H. Lammers, Guido Desmarets, Geert van Dijk, Francis Bathy, Eddy Vandenbouhede, Dorita Schattorie, Bert Van der Krieken, Bart Theunis, Arjan Berben, Natuurwerkgroep De Kerkuil vzw, Marietta Schramm, F. and H. Van den Broeck, Erwin De Meyer, Bernard Mortier. Gift cards: Werner and Marinelle Mory-De Paepe, Rita Saerens, Marleen Achtergaele, Lucrèce Maeckelbergh, Katty Van Severen, Kaatje Toye, Eddy Bruggeman, Dries Mertens, Helen Mortier, Lode Mortier, Jeroen Mortier, Jean-Marie Vande Waetere, Céline Gendron, Marc Van Iseghem, Koenraad De Wolf, Nadine and Patrick Rouckhout, Dirk and Dorien De Man DMD DESIGN BVBA, Bart Van de Vel, TMTS BV, Renaat Polfliet, Raes Marnix, Steven and Christel Rowaert-Stalpaert, Karel Schotsmans, Jozef and Mie Van Nieuwenhuyse, Maarten and Joline BekaertSnauwaert, Jan Tanghe, Jan Lenaerts, Dimitri and Mieke De Beul-Dennequin, Danny and Rita Schockaert, Verschuuren, Friedel and Lieve Nollet-Wemaere, Michiels Bernadette, De Zutter-Geerts, Elke Borms, Rita Saerens, Lieve De Vuyst, De Middeleer

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Acknowledgements

Lore-Mertens, CODE-Projects CV, Michel Vangheluwe, Marc Van Brantegem, Mia Vande Casteele, Etienne Vande Casteele, Versteels Etienne, Sigrid Balduck, Katty and Frank Westerlinck, Silvie Geerts, Marijke Van Nieuwenhuyse, Hilde Van Nieuwenhuyse, Bart Van Nieuwenhuyse, Geert Vanacker, De Middeleer Wim and Marianne, Filip and Veerle Renaer-De Clercq, Johny Huvaere, Geert Jackers, Ward De Groote, Marie-Claire Pierreu, Lieve De Middeleer, Karel Schotsmans, Mieke Casaert, Griet Van Den Bosch, Marleen Verhamme, Heidi Jansegers, Ingrid Diependaele, Koen and Lieve Dhoore-Jansegers, Saskia Collage, Michelle Mortier, Jef Melckebeke, Bjorn Crabs, Mireille Diependaele, Pierre Vidts, Hilde Snauwaert and Wim Duthoit. The authors are highly endebted to all people and organizations that supported them in this project and apologize to all those that were forgotten in this overview.

xviii Published online by Cambridge University Press

Executive Summary

In this book we synthesize the substantial literature and knowledge base on the Little Owl Athene noctua and detail the current understanding of its range-wide ecology, genetics and subspecies, its population status by country, and offer a conservation management strategy and outline a monitoring program for its conservation. The Little Owl (Plate 1) is a small (19–25 cm, 160–250 g), relatively long-legged nocturnal “chunky” owl with a short tail and a round head. The updated world distribution of the Little Owl and its subspecies is substantial, from the Atlantic coast of Britain and Iberia, north to Denmark, Sweden and Latvia, east to Asia Minor, Levant, Arabia, Asia to China and Manchuria, south to northern Africa and the Red Sea coast to Somalia and Eritrea. It has been introduced in New Zealand and England. It is considered fairly common to common in 45 countries, and uncommon, rare or a vagrant in 29 (78 in total) other countries. The Little Owl occupies open country with groups of trees and bushes, rocky country, deserts and semi-deserts with rocks, ruins, oases, pastureland with scattered trees, old orchards, along rivers and creeks with pollarded willow and other trees, parkland and edges of semi-open woodland, and farmsteads and urban areas with surrounding cultivated lands. Home-range sizes for a breeding pair of Little Owls tend to be small, averaging 0.5 km². Owls tend to be resident, with most young dispersing relatively short distances (between 600 m and 4000 m). The diet of the owl includes relatively small-bodied prey: invertebrates, rodents, reptiles, frogs and small birds. The current population status of this owl differs by country, with declines apparent or percieved in many countries. As it serves as an important ambassador for the small-scale, half-open landscape (ranging from pastoral landscapes with scattered trees to stony steppe deserts), we detail a conservation strategy and consistent survey methodology to further the significant and long-term international efforts being conducted by scientists, fieldworkers and volunteers. The update of this volume after two decades of international co-operation, aided by standardized methods for data collection, management and analysis, and dissemination led to the almost doubling of Little Owl publications, almost exclusively in English across the entirety of Europe and gradually expanding over most of its distribution range. Technological advances like PDF, GIS, advanced statistics, international standardized databases of geocoded and time-stamped pictures and sound recordings led to real-time exchange of papers, data, advice, images, sound recordings and maps, facilitating analysis and editing. The major difference was definitely the digital artwork

1 https://doi.org/10.1017/9781009103725.003 Published online by Cambridge University Press

https://doi.org/10.1017/9781009103725.003 Published online by Cambridge University Press

Executive Summary

FACT SHEET Athene noctua LENGTH

NEST CAVITY

19–25 cm

Natural cavity of nestbox approximately 3 m above the ground. Breeds in buildings, e.g., barns, sheds.

WINGSPAN

DISTRIBUTION

54–58 cm (Figure 0.1)

Resident throughout the global distribution area.

WEIGHT

TREND

160–250 g

Breeding populations decline because of loss of suitable habitat and mechanization of agriculture.

CHARACTERISTICS

MAXIMUM AGE

Small, compact, not much bigger than Common Blackbird. Brown with white spots. Yellow eyes.

Average life expectancy is 2.3 to 2.8 years.

FLIGHT

BREEDING SEASON

Fast, low, undulating flight. Broad, rounded wings.

April–May. Mostly 3–5 eggs, sometimes 6 or 7. 28–33 days incubation. After 32–34 days the young fledge.

CALL Mostly in spring, repetitive “kie-ew” or “miaw.” Territorial call elongated “kuuuup.” “kjie-kjie-kjie.” Juveniles “hssss.” HABITAT Diverse and near short-grazed grassy vegetation with hedges and older trees.

Figure 0.1 Silhouette wingspan of Little Owl.

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Executive Summary

by Joris De Raedt who worked with photographic input of owls and landscapes, collected by travelling from Iberia to China, to all the places where subspecies were discovered, with Google Maps. Drawings were custom made, as ordered by the authors, adapted, standardized and optimized, leading to excellent, tailor-made plates and illustrations. This state-of-the-art contribution aims at perfecting the knowledge and understanding of the species, study methods, proven conservation and management approaches that will undoubtedly lead to international co-operation between conservationists, well-trained academics and field workers across the entire distribution range of the Little Owl. The ambition of this book is to serve as yardstick for advanced citizen science and conservation management.

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Chapter 1: Introduction: Framework

For centuries, all across the world, humans have had a continuous and strong cultural relationship with owls (Marcot and Johnson 2003), traceable back 30 000 years to caves in France. Some cultures view owls as omens of back luck, sickness and death, while others view them as creator beings or helping spirits, having profound wisdom, oracular powers or the ability to avert evil. Depending on where you are within the range of the Little Owl, both of these divergent (bad or good omens) are still held for owls. In the mid twentieth century, drastic declines in several owl species attracted the attention of ornithologists, conservationists and researchers. Throughout Europe the decline of the species is mainly being caused by habitat destruction, especially due to the intensification and mechanization of agriculture. In order to counter this negative situation, scientists and conservationists have realized the need for international cooperation through a multidisciplinary approach. Early literature on the Little Owl reflected general studies on biology, distribution, diet, nesting and habitat. In 2008 our first edition of this book (Van Nieuwenhuyse et al. 2008) was published. The publication gave a review of most of the literature that was available at the time. Since then, substantial new findings on the Little Owl have been produced from a growing number of countries within the range of the owl. Since our first edition, much has changed. Literature is now always digitally available as pdf files, primarily in English or at least containing English abstracts. Contacting authors has become simple, no matter which country they originate from. High-quality digital pictures are now available which are time-stamped and georeferenced as input for solving the taxonomic challenges within the species, yielding sample sizes that are 10- to 100-fold times larger than in the early days of ornithology. The georeferencing has allowed virtual travel to landscapes by means of maps and local landscape pictures enabling landscapes across the entire range of the species to be discovered, even in the most remote and hostile countries. Last but not least, the evolution of the artwork proved crucial for this book, having high-quality illustrations available digitally created by Joris De Raedt. This technological advancement in merely one decade has allowed us to take a giant leap in relation to our first edition. The aim of this current book is to synthesize the substantial literature and knowledge base on this species and provide a more complete understanding of its range-wide ecology and conservation status. While rooted in science, this book has the principal aim of making the insights accessible to the wider international public. Recognition and appreciation of volunteer work is also of crucial importance for nature conservancy. Virtually unlimited input of volunteers not only helps to construct huge,

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Chapter 1: Introduction: Framework

standardized and reliable databases, it also helps to broaden the social network of nature conservation. In this way, nature conservancy is brought closer to the general public. The best guarantee for long-term conservation is to obtain the critical scientific insights resulting from co-operation between scientists and conservationists. The overall importance of detailed large-scale and long-term data collection by volunteers aided by scientists, and their contributions to applied as well as to basic scientific research, becomes increasingly important. Hence, a perfect blend of fieldworkers, data analysts, photographers and publishers is needed. Finally, the Little Owl is a useful ambassador for small-scale half-open landscapes (ranging from pastoral landscapes with scattered trees to stony steppe deserts) and as such deserves special attention. The species has a multitude of strategic features that make it a flagship of the rural environment: the species is very well known among the public, it is still present in reasonable numbers in most European countries and is readily observed, and the Little Owl can offer us insights into methods to implement nature restoration. Due to its “high cuddle factor” it is a perfect vehicle to transfer nature conservation values to the broader public. The framework of this book (Figure 1.1) reflects the complexity of the situation of the species at different scales. To position the Little Owl in a cultural context we look at the history and cultural traditions connected to the species and interpret this in the light of current knowledge (Chapter 2). Results of a large-scale research project dealing with owl myths and culture spanning over 6000 interviews collected in 26 countries are reported. Then we start with the bird itself and describe the taxonomy, the races to settle some taxonomic discussions (Chapter 3) and the morphology of the species (Chapter 4). Major progress has been made on genetic, morphological and biogeographical insights into the subspecies of the Little Owl. More data were collected on size and coloration of stuffed birds from various historical collections. Skins were measured and photographed, opening up new standardized, historical data. Genetics allowed for more clarification on the postglacial colonization of the different European subspecies. The distribution of the different subspecies and recent population estimates for the Western Palearctic are given in Chapter 5 to illustrate the diversity and local peculiarities. We then zoom in on both biotic and abiotic factors that influence Little Owl numbers. The habitat is described and the relationships between the landscape and the species are characterized in Chapter 6. A principal biotic factor inside the habitat is the food delivering the crucial energy input for the birds. Abiotic factors such as breeding cavities and perches show their importance for breeding and foraging efficiency to minimize the energetic cost for the birds (Chapter 7). Chapter 8 focuses on the breeding season and the genetic offspring of the birds, including clutch size, hatching and fledging success in relation the age of the birds. We then describe the behavior of Little Owls (Chapter 9), mainly based upon captive breeding data and complemented by almost two decades of webcam observations. The next section zooms in on the limiting factors for population regulation that influence the number of owls in a given geographic environment (Chapter 10). Input into the local population from outside is through immigration, re-introduction or supplementation. Local offspring feed back new owls into the local population too. Population outflow is observed

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Chapter 1: Introduction: Framework

HUMAN ACTIVITIES Conservation and Management (11) History and Traditions (2)

Research Priorities (12)

POPULATION Breeding Biology (8) Behavior (9) Population Regulation (10)

HABITAT OF THE SPECIES Habitat (6) Diet (7)

(7) SPECIES Fossils, Genetics and Taxonomy (3) Morphology and Body Characteristics (4) Distribution and Population Estimates (5)

POPULATION HABITAT SPECIES

HUMAN ACTIVITIES

Figure 1.1 Framework of the book.

through emigration and local mortality. Both external input and outflow, and local offspring and mortality influence the number of owls in a given location. Mechanisms that interact between local populations such as migration, metapopulation functions and the occurrence of sinks and sources place the individual parameters in a wider

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Chapter 1: Introduction: Framework

context. The insights obtained through population studies have proven to be crucial in conservation. After describing the main causes for declines in the species, we summarize the knowledge presented so far in the form of an international Little Owl conservation and management strategy and best practices (Chapter 11). This chapter will also discuss specific methods involved in reintroducing and translocating owls, captive breeding and releasing Little Owls into the wild to establish or improve local populations. Finally, we conclude this book with an overview of the key points raised and the most important open questions and advice for future studies (Chapter 12). Readers will find supplementary resources online at www.cambridge.org/littleowl. These include appendices as well as tables which previously appeared in the first edition (Van Nieuwenhuyse et al. 2008).

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Chapter 2: History and Traditions

Throughout human history, owls have variously symbolized dread, knowledge, wisdom, creator beings, death, witchcraft and religious beliefs in a powerful spirit world. A small but important body of literature is beginning to document the important aspects of owls and culture both across civilizations and through time (e.g., Medlin 1967, Simmons 1971, Stuart 1977, Holmgren 1988, Gimbutas 1989, Weinstein 1989, Enriquez and Mikkola 1997, Marcot and Johnson 2003). The most ancient representations of owls date from the Upper Paleolithic (13 000 BC) and are seen in two caves in France. The first site reflects three owls (generally considered Snowy Owls) in the “Gallery of the Owls,” in the French cave of Les Trois Frères in Ariège. A second site, in the Cave Chauvet represents a single “eared” owl that looks to be a Long-eared Owl (or Eagle Owl). Other prehistoric sites with owl art and symbolism are found in an array of locations around the world, such as the Victoria River region of northern Australia, the Columbia River region of northwestern USA and a Mayan cultural site in what is now Guatemala (Marcot and Johnson 2003). In the east Mediterranean, archaeological digs in Syria and Jordan have recovered anthropomorphized owls in the stone or clay as early as the prepottery Neolithic period (8000–6500 BC)(Gimbutas 1989: 190–195). Representations of Little Owls were found associated with the Xian culture (a society of agriculturists) in Inner Mongolia, dating from 8000–7500 BC (Schönn et al. 1991). Owls have been viewed by human societies in many different ways. Some viewed owls as a single group of animals (e.g., species were not differentiated and any owl was a bad omen), and others viewed large owls as bad (harbingers of bad luck, illness, death), whereas small owls were not viewed in this way. Still others were attentive to specific owl species for medicine, religious or hunting applications (and of course for current-day conservation purposes). Societies and societal values change, and whereas owls may have been viewed in one way or another in the past, current cultural views may differ. For example, during the Middle Ages, the owl was linked to witches and bad spirits, but nowadays in Turkmenia, the Little Owl is a sacred species and to kill one is a great sin (Shukurov in Khokhlov 1995). Another example of this change may be seen (in general) in Western culture, where newer perspectives pertain more to scientific understanding and conservation needs of owls; a specific example is how Spotted Owls have become symbols of old-growth forest protection. Included in her book on the religion of the Old European Great Goddess, Gimbutas (1989) presents a pictorial “script” consisting of signs, symbols and images of divinities. The main theme of goddess symbolism is the mystery of birth and death and the renewal of life, not only human but all life on Earth. Symbols and images cluster around

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Chapter 2: History and Traditions

the parthenogenetic (self-generating) Goddess and her basic functions as Giver of Life, Wielder of Death and as Regeneratrix. Overall, owls were deeply feared, and viewed as the harbingers of death. The Goddess in the guise of an owl was prominent in stone, pottery (e.g., terracotta figurines, burial urns), engravings on statues, schist plaques, bone phalanges laid in graves, drawings, amber figurines, wooden posts and gold sculptures in this prehistoric religion which extended from the Neolithic to the Early Bronze Age (general dates of 6500 BC to 2500 BC). Archaeological artifacts and images of owls in this religious context were generic or abstract in shape and pattern, and specific images distinguishable as Little Owls are not apparent. The features that characterize owls (round eyes and beak) can be seen on statue menhirs of southern France and the Iberian Peninsula, and in reliefs and charcoal drawings in the hypogea of the Parisian basin. A series of stelae and drawings of the Owl Goddess from Brittany and the Paris basin are depicted with breasts and one or more necklaces. Beautiful examples of owl-shaped burial urns dating from ca. 3000 BC come from the Baden culture in Hungary, from Poliochni on the island of Lemnos and from Troy. They have wings, the characteristic owl beak connecting arched brows, and sometimes a human vulva or a snakelike umbilical cord, symbols of regeneration. In continental Greece, gold sculptures have been found in the tholos tombe (Kakovatos, Pylos) and from shaft graves in Peristeria of the fifteenth century BC (Marinatos 1968: pl. 58). In spite of the gloomy aura which surrounds it, the owl has also been endowed with certain positive qualities, such as profound wisdom, oracular powers, and the ability to avert evil. However, this latter ambivalent image is a dim reflection, diffused through time, of the owl as an incarnate manifestation of the fearsome Goddess of Death. Perhaps she was respected for her grim but necessary part in the cycle of existence, as the agony of death which we take so much for granted was nowhere perceptible in this symbolism (Gimbutas 1989). With its large distributional range across Europe, the Middle East and Asia, and an ability to co-exist as a commensal with many human habitations, not surprisingly, the Little Owl has figured prominently in many cultural beliefs, and in a variety of ways. The common names given to this species across the countries are linked to its activity (Nightbird), to its voice (Kliwitt), to its morphology (Little Owl), to its food (Lark Owl or Sparrow Owl), to beliefs (Death Bird), to its habitat (House Owl, Willow Owl, Stone Owl) and to mythology (Bird of Minerve [Roman]). The Little Owl was first formally described to science by Giovanni Antonio Scopoli in 1769 (Scopoli 1769). The origin of its scientific name, Athene noctua, combines the genus Athene, derived from the goddess of wisdom Athena in Greek mythology, and the species noctua, as derived from the nocturnal characteristics of this bird of prey. An early name for the Little Owl “Strix passerina” was noted on Thomas Bewick’s 1797 drawing. This scientific name was not used as the name Athena noctua more accurately placed the Little Owl within the taxonomic naming convention of owls. While the origin of the English name Little Owl is probably linked to the size of the owl, the German and Dutch names – Steinkauz and Steenuil, respectively – refer to the open habitat of this species that it uses in many countries, where it breeds in piles of stones. Common names for the Little Owl in other countries include:

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Chapter 2: History and Traditions

Italy: Civetta Spain: Mochuelo Comun Portugal: Mocho France, Wallonia, Switzerland: Chevêche d’Athéna Germany, Austria, Switzerland: Steinkauz Greece: Κουκουβάγια (Koukouvaya) Denmark: Kirkeugle Netherlands, Flanders: Steenuil Turkey: Kukumav Russia: Domovogo sycha Georgia: Tchoti Hungary: Kuvik Mongolia: Chotny bugeechej Somalia: E’yu The relationship between the Little Owl and Greece is very long indeed, and is one of the most well-known affiliations between a particular owl species and a prominent society. This affiliation is again alive and prospering, with the new Greek 1 Euro coin showing the same Little Owl design as the former tetradrachm coin from 2500 years ago (Figure 2.1). In Greek mythology, Athena was the daughter of Zeus and originally a Mycenaean palace goddess. Her function later expanded to include the role of guardian of cities, war goddess, patroness of arts and crafts, and promoter of wisdom. Always shown modestly clothed and often armed, the Little Owl was her special bird. An emblem refers to some distinctive and characteristic or activity for which the issuing city is known. The Attica tetradrachm coin bearing an obverse head of Athena and reverse

Figure 2.1 Greek 1 Euro coin and former drachm silver coin showing the image of the Little Owl.

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Chapter 2: History and Traditions

owl with olive branch is perhaps the best known example of a city emblem. The Greek goddess Athena is a reference to the city (in Greek, Athenai) that honored her as its chief protective diety. The owl as Athena’s favorite bird, and the olive, which was one of the city’s most lucrative exports, in time came to stand for Athens throughout the Mediterranean world. With rich silver mines at Laurium at the southern tip of Attica, the Athenians were able to export bullion for foreign exchange at a time when most Greek states restricted coinage to home use. The necessity to create a standardized Greek currency that would be widely acceptable demanded a rigid uniformity in metallic purity, type and style seldom seen elsewhere in the Greek world. What resulted from ca. 525 BC onward was the famous series of tetradrachms that carried an obverse image of Athena’s head on one side, and a Little Owl with an olive branch and a cresent moon on the reverse. This type was kept in circulation for the next two centuries. The coins were made of silver, and their nickname “owls” become synonymous with Athen’s commercial power. The Obal, Stater, Drachm, Didrachm, Tetradrachm, Octodrachm, and Decadrachm are terms for common denominations based on these weight systems. About 77 BC, the Roman scholar Pliny the Elder assembled more information about the owl in a few chapters of Book X in his Historia Naturalis. He specified the Little Owl, the Eagle Owl and the Screech Owl. His observations were laced with beliefs not entirely sound by today’s zoological standards, but were studied as gospel during the Middle Ages (Medlin 1967: 20). Little Owls are also of historical importance for the Italian Peninsula since they appear in some classic fables (Mastrorilli 2005). Fedro’s classic fable “The Cicada and the Little Owl” describes the capture of a cicada by a Little Owl during its diurnal hunt. The fable describes the owl’s hunting strategy as a sign of its intelligence. It also demonstrates that the Little Owl was a loved species in the Roman period. XVI. Cicada et Noctua Humanitati qui se non accommodat plerumque poenas oppetit superbiae. Cicada acerbum noctuae conuicium faciebat, solitae uictum in tenebris quaerere cauoque ramo capere somnum interdiu. Rogata est ut taceret. Multo ualidius clamare occepit. Rursus admota prece accensa magis est. Noctua, ut uidit sibi nullum esse auxilium et uerba contemni sua, hac est adgressa garrulam fallacia: “Dormire quia me non sinunt cantus tui, sonare citharam quos putes Apollinis, potare est animus nectar, quod Pallas mihi nuper donauit; si non fastidis, ueni; una bibamus.” Illa, quae arebat siti, simul gaudebat uocem laudari suam, cupide aduolauit. Noctua, obsepto cauo, trepidantem consectata est et leto dedit. Sic, uiua quod negarat, tribuit mortua. Fedro’s classic fable (Latin version) 12 https://doi.org/10.1017/9781009103725.005 Published online by Cambridge University Press

Chapter 2: History and Traditions

Leonardo da Vinci (1452–1519) wrote one fable on Little Owls and Thrushes. He described the use of the Little Owl as a “decoy” during the hunting of Thrushes. This is an important source of evidence that Little Owls were used for hunting after the Middle Ages. Illustrations became as important as word descriptions to naturalists and others. Conrad Gessner (1516–1565), from Zurich, Switzerland, authored one of the first printed books containing birds in the sixteenth century. His third volume, published in 1555, was the largest in a series of five books on animals (i.e., Historia animalium), and contained a nice image of a Little Owl (“Night Owl”) (Figure 2.2); [“Von der Eul/oder Nacht-Eul/und erstlich von ihrer Gestalt Ulula”].

Figure 2.2 Image of the Little Owl from Conrad Gessner’s “Vogel-Buch” (bird book) published in 1555.

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Chapter 2: History and Traditions

Thomas Bewick published his authoritative History of British Birds in England in 1797 and 1804. Bewick rejected the copper-engraving medium that was common to book illustration at that time, in favor of incizing the end grain of a hardwood block with a graver, thus achieving detail in picture and durability in printing that was previously impossible in wood. Bewick’s first edition of the History illustrated the Long-eared Owl, Short-eared Owl, a female Horned Owl, the Snowy Owl, Tawny Owl, and Little Owl (Figure 2.3). In the book Birds of Europe, Nilsson in Gould et al. (1837) named the Little Owl Strix nudipes (Figure 2.4). Refinements were made in the drawings,

Figure 2.3 Image of the Little Owl from Thomas Bewick’s 1797 History of British Birds.

Figure 2.4 Little Owl image from the Birds of Europe Vol. 1 (Raptors), 1837 [Strix nudipes (Nilsson), Noctua nudipes (Mihi) – illustrated by Edward Lear.

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Chapter 2: History and Traditions

Figure 2.5 Engraving of a Little Owl from Howard Saunders’s Manual of British Birds (1889).

and Howard Saunders published his significant An Illustrated Manual of British Birds in 1889 (Figure 2.5). Until the beginning of the twentieth century, hunters in France enjoyed shooting the Little Owl (Delamain 1938). In the ninteenth century, despite the prejudices against this species, the Little Owl was also appreciated by people and held as a captive bird (von Risenthal 1879) and sold by fowlers in Germany (Wemer 1910). In France (Crespon 1840) and in Belgium (Dupond 1943), the Little Owl was used to hunt little birds such as larks, because the mobbing behavior of passerines towards the Little Owls was a good technique to attract them. In Italy, Little Owls were domesticated and kept (with their wings clipped) in houses or gardens, where they caught rodents, slugs and insects (Goddard 1917). A particularly interesting example of the cultural use of Little Owls comes from Crespina, Italy. Crespina is located 25 km from Pisa in the Toscana region of Italy. The community has a specific monument dedicated to the Little Owl called the “Place of the Little Owl Fair” (Schaaf 2005). This little town was a center for the rearing of owls in captivity to be used in a Little Owl competition. Around a century ago (ca. 1900), Little Owls were taken out of their nests, reared and put in special boxes in farms of this Italian region to be used as bait for the hunting of larks. They were then sold on the Little Owl market while tied up on a roost (for an example of this market, see Figures 2.6–2.8). The nobility (upper-class people) commonly hunted in the countryside using

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Chapter 2: History and Traditions

Figure 2.6 Cover of the journal La Domenica del Corriere in 1903 represented the Little Owl market.

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Chapter 2: History and Traditions

Figure 2.7 Drawing from 1896 showing a seller of Little Owls and interested women.

the Little Owls as bait. People pulled the tethers to stimulate the Little Owl to fly; larks were attracted by the owl and were themselves caught in nets. There was a “civettaio” (“Owl man” or “Owl-keeper”) charged with tending to the Little Owls. The owl market of Crespina took place annually on September 29. At these occasions, it was possible to listen to a range of bird imitators and attend the Little Owl competition. This hunt reflects an ancient tradition that started in 350 BC and lasted until the twentieth century in Italy, and from the seventeenth to the twentieth century in Germany. A national policy in Italy (L157/1992) and a regional policy approved in Toscana (L3/1994) have recently banned the annual owl market. The laws forbid the killing, catching or keeping of any owl species in aviaries, or to possess dead owls or parts of them. The use of owls as bait is also forbidden. Because of the traditional aspect of the hunting method, the policy was modified to allow some rearing stations

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Chapter 2: History and Traditions

Figure 2.8 Photo of a hunter and his wife at Crespina market.

for wild animals. A Little Owl rearing station in Crespina covers 2 ha and was sponsored by hunters. Little Owls were introduced in England and in New Zealand at the end of the nineteenth century and beginning of the twentieth century. After its release, the species was considered a pest by many gamekeepers and farmers in England (Dawson-Smith 1913). The history and traditions of the Little Owl are truly long, rich and varied, and grow with additional recoveries of artifacts from archaeological sites, as well as evolving cultural views. In closing this chapter, we urge reviewers of owl myths, traditions and lore to closely scrutinize the information they assemble, to determine whether the ideas and symbolism described in text and artifacts still apply in contemporary societies, or whether they are part of a colorful but quaint past. Whatever the outcome, no doubt the lure and fascination of the Little Owl will continue to make a significant impression on peoples of the world.

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Chapter 2: History and Traditions

Figure 2.9 Belgian Little Owl beer “Steenuilke” brewed by Brouwerij De Ryck as part of a European Leader project dedicated to the conservation of the species in Flanders.

Many countries use the image of Little Owls on a diverse range of postage stamps. Human appreciation for the Little Owl continues to grow, and the image of the owl has recently been used for the marketing of a Belgian Little Owl beer (Figure 2.9).

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Chapter 3: Fossil Evidence, Taxonomy and Genetics

Chapter Summary Different owl species and subspecies used to be defined in the early days of taxonomy uniquely based upon morphological features like size and color in specific geographical regions across the world. Recently, more differentiators are taken into account to define new species to avoid upgrading them from a subspecies based upon only one or two aspects. We consider the following concepts in the discussion of the subspecies of the Little Owl, letting the old taxonomy prevail if there is a lack of alternative multidisciplinary evidence. The biological species concept (Mayr 1940) takes biological characteristics into account, the morphological concept studies especially morphometrics and coloration of the bird. Recently, a third principle was fully adopted, the so-called phylogenetic concept (Cracraft 1983, Dickinson and Remsen 2013). Through mitochondrial DNA studies, a lineage can be established that eventually leads to a common ancestor. Different species thus have different ancestors, up to some point in the past. This research is complemented with fossil evidence for the evolution of species. Vocalizations of Little Owls across the range are increasingly documented and taken into account. The last approach considers the geographical distribution and the use of validated, geocoded, high-quality photographic input. In this chapter we present the current fossil evidence for ancestors of the Little Owl. We describe the historical context in which subspecies have been defined. For a while it was a kind of international sport to distinguish as many subspecies as possible. Hence, there was quite some evolution in the insights on the subspecies. We illustrate the way the subspecies were described for which we now have evidence for their relevance. We consider 14 subspecies of Little Owl where we have found substantial evidence. This means that we have one more subspecies compared to the 13 subspecies that were retained in Van Nieuwenhuyse et al. (2008). Since then Athene noctua impasta has been studied in more detail and is found to deserve the status of real subspecies which we will justify here. We cite the original descriptions of the subspecies as found in historical publications in the original language and translated into English. We combined the textual descriptions of Hartert (1913) and Vaurie (1960) based upon 216 skins in four museums with those of Pellegrino et al. (2020) based on 282 skins from five other museums and validated the descriptions by studying over 5000 georeferenced highquality pictures (macaulaylibrary.org) across most of the distribution range, including Somaliland (somaliensis) and Eritrea (spilogastra). We were able to validate and

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3.1 Fossil Evidence

complement all textual descriptions through pictures of typical plumage for the subspecies, but we equally found aberrant plumage and clinal variations across the distribution areas of most subspecies during the photographic validation. Futher, we validated morphological trends and differences in geographical areas related to each individual subspecies in detail by studying high-quality standardized pictures of the skins of some of the type specimens (where available) from five major museums (Pellegrino et al. 2020). Each subspecies illustrated by Joris De Raedt was based upon pictures that were taken at or near the type locations of the subspecies. Typical landscape elements were obtained by studying Google Street View or available characteristic landscape pictures presented by Google at or near the locations of the owl pictures. Extraordinary specimens are illustrated separately in dedicated plates that are only georeferenced without clean subspecies classification.

3.1 Fossil Evidence Little Owls are small strigiform birds commonly present in Mediterranean islands during the Pleistocene and Holocene with four fossil species: Athene angelis (MourerChauviré et al. 1997) from the Middle and Late Pleistocene of Corsica, Athene cretensis (Weesie 1982) from the Late Pleistocene of Crete and Armathia, Athene trinacriae from the Middle Pleistocene of Sicily, and Athene vallgornerensis (Guerra et al. 2012) from the Early Pleistocene of the island of Mallorca (Balearic Islands). Athene trinacriae (Pavia and Mourer-Chauviré 2002) is described within the fossil assemblage of some Middle Pleistocene localities in Sicily. The species is similar in size to the extant A. noctua, but differs by its longer legs and some morphological characteristics, probably as a result of a mainly terrestrial lifestyle. Athene trincacriae is smaller than A. angelis from the Pleistocene of Corsica, and has a longer and thinner tibiotarsus and tarsometatarsus; it also differs by its smaller size and by its relatively longer legs from the endemic form from the Pleistocene of Crete and Armathia, Athene cretensis. Athene vallgornerensis (Guerra et al. 2012) was discovered in a fossil assemblage from the Early Pleistocene of the island of Mallorca (Balearic Islands) in Cova des Pas de Vallgornera (Llucmajor, south of Mallorca). The presence of this new species in Mallorca improves the knowledge of the evolution of Little Owls on the Mediterranean islands, where two main types of insular Little Owls seem to have evolved, one displaying a short and robust tarsometatarsus (A. angelis and A. vallgornerensis) and the other with a slender and longer tarsometatarsus (A. cretensis and A. trinacriae), associated with relatively shorter wings, which have been interpreted as indicative of more terrestrial lifestyle than Athene noctua (Weesie 1982, Pavia and Mourer-Chauviré 2002, Louchart 2005). Long legs are also characteristic of A. cunicularia that suggests terrestrial habits, while A. angelis would have had a less terrestrial lifestyle, according to its body shape and proportions (Louchart 2005). The lifestyle of A. vallgornerensis remains unkown.

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Chapter 3: Fossil Evidence, Taxonomy and Genetics

The presence of endemic species of Athene on Mediterranean islands during the Pleistocene is related to particular environmental and ecological conditions. The long geographical isolation of the islands from the mainland, the presence of abundant terrestrial prey and the absence of terrestrial carnivores, together with the sedentary habitus of the genus, favored genetic isolation and the formation of endemic forms, as was also suggested by Weesie (1982). The extinction of the endemic forms is probably related to other ecological factors, such as paleoenvironmental changes or competition with terrestrial predators, e.g., foxes and hedgehogs, which arrived from the mainland. Their arrival is due either to natural colonization after the new connection of the mainland with the island, as is the case of Sicily, or to human introduction, as is the case for Crete (Weesie 1982), or both. Such colonization would be a cause of concern for the extinction of Athene trinicriae; this species in fact probably mainly fed on small endemic rodents and its extinction is related to the arrival of the new faunistic element of the Elephas mnaidriensis Faunal Complex. The present distribution of Athene noctua on the major Mediterranean islands is probably due to recent colonization during the Late Pleistocene. During the Early and Middle Pleistocene, in fact, most of the Mediterranean islands were much more isolated because of the higher sea level. During the Late Pleistocene the lower sea level, as a result of eustatic changes and tectonic activity, made it possible for some terrestrial animals, or sedentary birds like Athene noctua, to spread on many Mediterranean islands. Fossil Little Owls Athene noctua have been described from the Pleistocene and prehistoric period from 14 sites in 11 countries across the species’ range (Brodkorp 1971, Andrews 1990).

3.2 Discovery of the Species Since the Little Owl is one of the most synanthropic owl species in Europe, it is not surprising that the species was already known to ancient authors such as Pliny the Elder, since the Little Owl also inhabited Roman cities (Jashemski and Meyer 2002). The Little Owl was later described or mentioned in many early ornithological works in Europe under the names Noctua (Magnus 1495), De Noctua (Gesner 1555, Aldrovandus 1646, Jonston 1650) and Noctua minor (Willughby and Ray 1676). Many of these works contain detailed descriptions and even illustrations (Figure 3.1). However, official scientific naming began with the publication of the 10th edition of Systema Naturae by Carl Linnaeus (1707–1778) in 1758. Linnaeus (1758) described most European owl species with descriptions that are still valid today, but also created some major confusions, especially with species that do not live in Sweden and with which Linnaeus therefore had no real experience. This includes the Little Owl, which occurs in most parts of Europe, but not in Sweden. Under the name Strix passerina, Linnaeus (1758) described an owl resembling the Little Owl, citing several references to older European authors who described the bird extensively. Linnaeus (1758) even referred to illustrations that clearly depicted the

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3.2 Discovery of the Species

Figure 3.1 Little Owl illustration from Ornithologiae (Aldrovandus 1646) named De Noctua.

Little Owl, such as Frisch (1734–1763; Figure 3.2). The description by Linnaeus (1758) was later taken up by many authors, introducing Strix passerina as the accepted scientific name for the Little Owl (e.g., Latham 1790, Naumann 1803, Temminck 1815, Boie 1822, Freyer 1842). The first to revise Linnaeus’s owl descriptions was the Swedish ornithologist Peter Gustaf Tengmalm (1754–1803). He checked several references and illustrations such as Aldrovandus (1646), Jonston (1650) and Frisch (1734–1763) and found that this small Italian owl does not live in Sweden and that Linnaeus (1758) certainly made a mistake (Tengmalm 1793). There are two other small owl species similar to the Little Owl that live in Sweden. Tengmalm (1793) referred to the illustrations of Olof Rudbeck Jr. (1660–1740), professor at the University of Uppsala, whose student was Carl Linnaeus (Walters 2003). Rudbeck’s excellent hand drawings were

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Chapter 3: Fossil Evidence, Taxonomy and Genetics

Figure 3.2 Little Owl illustration by Johann Leonhard Frisch (1734–1763) cited by Linnaeus (1758) in his description of Strix passerina.

admired by Linnaeus and became his main references in describing bird species (Linnaeus 1746), although they were not mentioned in Systema Naturae (Linnaeus 1758). From these illustrations, Tengmalm (1793) recognized that Linnaeus (1758) described the Boreal Owl under the name Strix funerea (Figure 3.3) and the Pygmy Owl under the name Strix passerina (Figure 3.4). Subsequently, Tengmalm (1793) concluded that the Little Owl was actually described by Scopoli (1769) from Carniola (now Slovenia). Low accessibility to references largely contributed to misinterpretations of the original species descriptions in the eighteenth and nineteenth centuries, and even Tengmalm’s (1793) correct designation of Strix noctua for the Little Owl was later incorrectly attributed to the Boreal Owl by Retzius (1800).

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Figure 3.3 Illustration of the Boreal Owl (Aegolius funereus) by Olof Rudbeck Jr., which matches the description by Linnaeus (1758) Strix funerea.

Figure 3.4 Illustration of the Pygmy Owl (Glaucidium passerinum) by Olof Rudbeck Jr., which matches the description by Linnaeus (1758) Strix passerina.

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Chapter 3: Fossil Evidence, Taxonomy and Genetics

Figure 3.5 Joannes Antonius Scopoli (1723–1788) – the author of the first scientific decription of the Little Owl (Athene noctua) according to binominal Linnean nomenclature.

However, even Joannes Antonius Scopoli (1723–1788; Figure 3.5), the author of the first scientific description of the Little Owl according to Linnean binominal nomenclature, was misled by the vague descriptions from Linnaeus (1758). In Annus I. Historico Naturalis, Descriptiones Avium, Scopoli (1769) actually described the Little Owl in great detail under the name Strix passerina and supplemented the description by Linnaeus (1758) with the remark that the species is used by hunters to catch passerines and breeds in chimneys. The Italian (Civetta) and German names (Tschiavitl, Hauseule, Stockeule, Käuzlein) also clearly designate the Little Owl he found in Italy. The description by Linnaeus (1758) was apparently so clear to Scopoli that he had no doubt about it and did not refer to it, even in his correspondence with Linnaeus, in which they discussed, for example, the species identity of the Scops Owl (Otus scops) (Soban 2004). Nevertheless, the name Strix passerina was already used by Linnaeus (1758) for the Pygmy Owl, as clarified by Tengmalm (1793). Therefore, the second description of the Little Owl by Scopoli (1769) as Strix noctua must be taken into account (Tengmalm 1793, Hartert 1913): Strix noctua Diagn. Pallide rufa, fuscisque maculis longitudinaliter variegate. Irides flava. In M.p. (Musei Proprii) Carniola indigena, et in sylvis circa Labacum copiosa. Statura Columbae.

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3.3 Discovery of the Subspecies

Strix noctua Diagn. Pale red, with brown spots variegated longitudinally. Iris yellow. In M.p. (Scopoli’s own collection) from Carniola where it is abundant in the woods around Ljubljana. The size of Columba [probably the Stock Dove (Columba oenas) is meant here, described under the number 177 in Annus I. Historico Naturalis]. Hartert (1913) rated the description as poor and even uncertain, but it should be given as benefit of the doubt. J. A. Scopoli apparently knew the bird well, because he had the type in his own collection (Scopoli 1769), which was later destroyed, and also the longitudinal spots and yellow eyes agree with the Little Owl, although the size of a pigeon, which probably refers to the Stock Dove (length 28–32 cm), is slightly larger than the Little Owl (21–23 cm). J. A. Scopoli conducted research mainly between 1754 and 1769 in the former Duchy of Carniola, which existed in the former Holy Roman Empire and includes the territory of the western half of Slovenia (Vrezec et al. 2017). Scopoli (1769) referred to the city of Ljubljana as the type locality for Strix noctua, where the species bred until recently (Tomé et al. 2005, Berce 2019).

3.3 Discovery of the Subspecies 3.3.1 Historical Rationale For a while it was a kind of international competition to distinguish as many subspecies as possible. Subsequently, of course, extensive discussion arose about how many subspecies should or should not be distinguished and on the basis of what. Table 3.1 gives an overview of the subspecies distinguished over the years by various authors. Dickinson and Remsen (2013) state that many subspecies were distinguished at a time when even the simplest statistical tests were not yet available. Subspecies were mainly distinguished using differences in structural sizes or subtle nuances in the plumage (morphological concept). However, many differences are arbitrary or based on extremes and for that reason might be artificial. Too small samples, insufficient comparisons with recognized species and too little control for wear and tear of the seasonal plumage or discoloration increase the problem (Dickinson and Remsen 2013). The division into subspecies is still ongoing, e.g., Hart et al. (in Del Hoyo et al. 2016) note that many races or subspecies should probably be considered intermediate populations or reflect individual variation with unclear geographic boundaries. For example, the subspecies vidalii and indigena meet in a wide area in northwestern Russia, noctua and vidalli ranges border from southern France to the Czech Republic and Slovakia, and noctua and indigena meet in the Western Balkans. Many differences were not detected in the field, but were described by skins. Hartert (1924) describes in a letter how he compared 29 saharae with 15 lilith to establish that they differed too much from each other to be counted as belonging to the same subspecies. A first overview of the different subspecies of the Little Owl was given by Hartert (1913). It was not yet complete, as new subspecies were discovered in subsequent years

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Table 3.1 Overview of the subspecies distinguished over the years by various authors Van Howard Nieuwenhuyse and et al. Mikkola Moore

Clements IOC

2008

2013

2015

1 1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1

1 1

1 1

1 1

1 1 1 1 1 1 1 1 1 1 1 1

Subspecies

Year Author

Country

1913

A. n. noctua A. n. glaux A. n. bactriana A. n. indigena A. n. vidalii A. n. spilogastra A. n. plumipes A. n. orientalis A. n. somaliensis A. n. sarda A. n. saharae A. n. lilith A. n. solitudinis A. n. ludlowi A. n. impasta

1769 1809 1847 1855 1857 1863 1870 1873 1905 1907 1909 1913 1924 1926 1928

Italy France UK Germany Germany Germany UK Russia Germany Germany Germany Germany Germany UK UK

1 1 1 1 1

Scopoli Savigny Blyth Brehm Brehm Heuglin Swinhoe Severetzov Reichenow Kleinschmidt Kleinschmidt Hartert Hartert Baker Bangs and Peters

Van Nieuwenhuyse, Johnson and Van Harxen

König and Hartert Peters Vaurie Schönn Weick Wink Weick

1

1 1 1

9

1940 1960

1991

2006 2008 2008

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1 1 1 1

1 1 1 1 1 1

1

15

13

1 1 1 1 1

1 1 1 1 1

2016 2023

1 1

1 1 1 1 1 1 1 1 1

1

1

1

1

1 1

1

1 1

1

1 1

1 1

1 1

1 1

13

10

12

8

13

7

13

13

13

14

1 1

1 1 1 1 1 1 1 1 1

2012

1

1 1

3.3 Discovery of the Subspecies

and he disregarded spilogastra and somaliensis as non-Palearctic. A first, complete overview with 17 subspecies was presented by Peters (1940). Vaurie (1960) retained only 13 subspecies, something that most current lists have followed so far (Van Nieuwenhuyse et al. 2008, Dickinson and Remsen 2013, Clements et al. 2015, Gill et al. 2021). The subspecies impasta was discussed by Vaurie (1960) but not retained due to a very limited sample size of two specimens available from Bangs and Peters (1928) and seven in his own collection plus a possible bias in coloration due to very fresh plumage that could have explained the dark coloration rather than being a conclusive differentiation. However, Vaurie could identify a clear difference in the size of seven newly collected skins from impasta being smaller in wing length than ludlowi and larger than plumipes. Furthermore, recent morphological insights (Lei et al. 1997) and genetic analysis of the Chinese subspecies (Qu et al. 2002) confirm the relevance of A. n. impasta.

3.3.2 Discovery All subspecies of the Little Owl were described in the nineteenth century and the first quarter of the twentieth century with noctua (1769) as the exception and impasta (1928) as the last. Discovering new species was relatively easy at that time since most were still unknown. People travelled in all directions, i.e., the French to Egypt, the Germans first into Europe, later to northeast Africa and the Arab countries, the English to India and the surrounding area, and the Russians to the Caucasus (Walters 2003). They were adventurers, looking for the thrill of the unknown. They were scientists, yearning for new knowledge. Above all, they were pioneers, going where others had not yet gone. They shot and gathered birds; full shiploads were sent to museums (Mearns and Mearns 1998). It was not until 1822 that Ferdinand Boie – a German lawyer, entomologist, herpetologist and ornithologist – placed Little Owls in the Athene genus. The discovery of the different subspecies is presented in chronological order. 1.

Athene noctua noctua (Scopoli 1769) Italy to Slovakia, NW Romania and Croatia. Type locality: Ljubljana (Slovenia) See species discovery above

2. Athene noctua glaux (Savigny 1809) Coastal areas North Africa, Nile Valley, SW Israel, Arabian Peninsula. Type locality: Egypt The first subspecies described is Athene noctua glaux. In the years 1798 to 1801, Napoleon Bonaparte made a fierce attempt to conquer Egypt. In addition to increasing the French sphere of influence in this part of the world, the campaign also served a scientific purpose. In the wake of the Armée d’Orient, a small army of scientists of various backgrounds went along, with the aim among other things of describing the rich and hitherto virtually unknown flora and fauna of the Orient. Among them was the zoologist Marie Jules César Lelorgne de Savigny. Although initially responsible for the study of invertebrates, he had a special interest in ornithology. He probably derived the name glaux from ancient Greek, where glaux (γλαύξ) means owl and is derived from

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glaucos, which indicates something as sparkling or shiny (in relation to the eyes). The Greek goddess of wisdom, Pallas Athene, was also referred to as glaukopis: “she with the beautiful owl eyes” (Schönn et al. 1991). Savigny used the name Noctua glaux. 3. Athene noctua bactriana (Blyth 1847) Lower regions of Urals, Transcarpathia and Iran to south Kazakhstan, West Pakistan Type locality: Old Candahar (Afghanistan) The subspecies bactriana was first described in a periodical edited by Edward Blyth, who is referred to as the father of Indian ornithology. From 1841 to 1863 he curated the Asiatic Society of Bengal Museum in Calcutta. In that capacity he was regularly more concerned with ornithology than with museum matters. He started writing articles, and trading and shipping wild animals from India to wealthy collectors in England. He was a contemporary of Charles Darwin and corresponded with him. He provided Darwin with a lot of information about birds and other animals in India. Blyth got his information on bactriana from Thomas Hutton, Captain in the 37th Bengal Native Infantry. Hutton served in the First Soviet–Afghan War (1839–1840) between England, Russia and Persia. After his retirement he developed into an all-round naturalist. In 1847 he described the new subspecies bactriana as common among the rocks and ruins of old Candahar. The article was published in the Journal of the Asiatic Society, edited by Blyth, who claimed ownership while honoring Hutton in the English name for bactriana as “Hutton’s Little Owl.” The name bactriana (or bactrian as Hutton originally calls it) refers to the region of northern Afghanistan around Bactra (now Balch) that was called Bactria in ancient times and in 328 BC was conquered by Alexander the Great. 4. Athene noctua indigena (Brehm, C.L. 1855) Western Balkan peninsula to southern Russia, in the south to Greece, Cyprus, Turkey, North Levant and Transcaucasia Type locality: Attika (Greece) Christian Ludwig Brehm was a German priest and ornithologist and is considered one of the greatest bird connoisseurs of his time. In 1824 he was the publisher of Ornis, the world’s first ornithology magazine. Brehm owned a collection of more than 15 000 skins that proved to be of great importance for a better understanding of species and subspecies. He called indigena “Der Griechische Steinkauz” and wrote not only that it lived in Greece, but also that it migrated to Egypt, which was only speculation. The name indigena comes from Latin and means “out of the land” or indigenous. Brehm here probably referred to the cradle of the family, the Greek city-state of Athens. On Greek tetra- and decadrachm coins from 500 BC the Little Owl is already prominently depicted. Brehm also mentioned A. n. meridionalis (southern Little Owl) as a synonym of A. n. glaux. 5. Athene noctua vidalii (Brehm A.E. 1857) Western and Central Europe, east to the Baltic states and Belarus Type locality: Murcia (Spain) Alfred Eduard Brehm, son of Christian Ludwig Brehm, is famous for his monumental work Brehms Tierleben, published in 1863–1869.

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Brehm gained much of his knowledge during his travels abroad. He took part in a fiveyear expedition to Northeast Africa and travelled to Scandinavia and Siberia. On his journey to Sinai in the 1850s he was accompanied by Theodor von Heuglin who described the subspecies spilogastra a few years later. In 1856 Alfred Brehm left with his brother Reinhard for a two-year trip to Spain. There he saw in rock walls everywhere – what he presumed was – a new Athene species, which he affectionately called “Vidals Käuzchen.” In the Allgemeine Deutsche Naturhistorische Zeitung he described it as a new species of Athene vidalii. Dedicated (nobis), on behalf of father and sons Brehm, to his “most loving friend” Ignatio Vidali, director of the zoological museum in Valencia. In June of that year they had visited the university museum in Valencia and there they met Ignacio Vidali y Cros. Together they went on a few collection excursions. Ignacio was considered an excellent ornithologist and helped both brothers financially. Alfred returned to Germany to become director of the Zoologischer Garten in Hamburg and the Berliner Aquarium Unter den Linden. 6. Athene noctua spilogastra (von Heuglin 1863) Northeast Sudan, Eritrea and Northeast Ethiopia Type locality: coast of Abyssinia near Massawa (Eritrea) Theodor von Heuglin was a German explorer and ornithologist. He made several trips to Africa, in particular to countries along the Red Sea. In 1855 he published his opus magnum Übersicht der Vögel Nordostafrikas in which he described 754 species. During one of his travels in 1862 he discovered along the coast of Abyssinia (now Ethiopia/ Eritrea) the “African Höhlenkauz,” which he named Noctua spilogastra (von Heuglin, 1863). He found nests in burrows with a diameter of 10–15 cm in the high, almost perpendicular walls of water channels. The name spilogastra is composed of the Greek words for stain (spilos) and gaster (belly) and means (white) spotted belly (Heuglin: abdomine albidis). The illustration of the subspecies (Figure 3.6) gives the impression that the artist had never seen the animal nor had a skin available and had to draw based upon textual descriptions. 7. Athene noctua plumipes (Swinhoe 1870) Southern Altai Mountains and Mongolia to Transbaikalia and north (central) and northeast China Type locality: Shuato in Sichuan Province (China) Robert Swinhoe – the first Western consul on Formosa, Taiwan – was an avid amateur ornithologist. His diplomatic status gave him unique access to China and Taiwan at a time when the door to parts of the empire was still firmly locked to Western researchers. He published more than 120 articles on the region in which he gave a first description of 231 (sub)species of birds and 26 mammals. He was a contemporary of Darwin and admirer of his ideas. On September 28, 1870, near Shato (Shuato in Sichuan Province), he saw a small owl basking on the ruins of a brick oven. They could easily reach it. The animal was notable for its feathered feet: “feet covered with shorter hair-like feathers, just showing scaled of end of toes.” His proposal to recognize it as the new subspecies plumipes (with feathers on the foot) was adopted by the professional ornithologists of his day.

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Figure 3.6 Athene noctua spilogastra (von Heuglin 1863).

8. Athene noctua orientalis (Severtzov 1873) Pamir and the Tan Sien Mountains to Qinghai in western China Type locality: Turkestan The orientalis subspecies was first described by the Russian paleontologist and zoologist Nikolai Alexeyevich Severtzov, son of Alexei Petrovich Severtzov who, like Savigny (ssp. glaux), went to Egypt under Napoleon’s command. Nikolai Alexeyevich also travelled a lot. While trekking through the steppes of Kyrgyzstan, he was seriously injured in an attack by Turkestan bandits and held prisoner by them for a month. He collected a lot of material on the taxonomy of birds in Russia and the former Turkestan. He also had a large collection of no fewer than 12 000 specimens. He published his findings in Messages of the Imperial Society of Lovers of Natural Sciences, Anthropology and Ethnography in Russian. 9.

Athene noctua somaliensis (Reichenow 1904) Somaliland. Type locality: northern Somaliland

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Anton Reichenow was a German ornithologist specializing in African birds. He was married to the daughter of Jean Cabanis, founder of the Journal für Ornithologie in 1853, one of the oldest ornithological journals. In 1894, Reichenow succeeded his father-inlaw as editor, a position he would remain in for more than 25 years. He undertook expeditions to West Africa in 1872 and 1873. From 1874 to 1921 he was associated with the Humboldt Museum in Berlin. He recorded his findings in Die Vögel Afrikas, which appeared in three volumes in the period 1901–1905. The East African subspecies somaliensis comes off very scantily in its first description in Die Vögel Afrikas. In part 1, in which the owls are discussed, of the Little Owls only the subspecies spilogaster, previously described by Heuglin, is mentioned. Only in the addendum to the third part does Reichenow mention somaliensis incidentally as a subspecies of spilogaster which was then regarded as an independent species (Reichenow 1904). The author assumed certain statements, indicating that no real hard evidence had been collected, nor did he indicate the name of the observer. Somaliensis obviously refers to Somalia. 10. Athene noctua sarda (Kleinschmidt 1907) Type locality: Sardinia (Italy) Konrad Ernst Adolf Otto Kleinschmidt for decades combined the profession of an evangelical clergyman with that of an ornithologist. He had great significance for the animal system through the introduction of the term “Artenkreis.” Kleinschmidt recognized that there are species that, while morphologically different, can mate and reproduce successfully with each other and must be classified as one and the same species. The renowned German–American evolutionary biologist Ernst Mayr built on his ideas with the name superspecies, nowadays polytypical species, a species that consists of several subspecies and of which the Little Owl could be considered an excellent example. In Falco 3 (1907) Kleinschmidt describes the geographic variation of 96 Little Owls (which he still classifies in the genus Strix) on the basis of skins from his own and Erlanger’s collections, supplemented with some from a few other sources. Kleinschmidt mentioned for the first time the subspecies sarda occurring in Sardinia and distinguished by the very small spots on the shoulder feathers that are divided in two by a dark shaft stripe along the length of the feather. Currently the taxon sarda is not accepted as a valid subspecies (Gill et al. 2021) although there is strong genetic support for it (Pellegrino et al. 2015). 11. Athene noctua saharae (Kleinschmidt 1909) Sahara, east to the Red Sea (excluding the Nile Valley), and Arabian Peninsula Type locality: Mouleina by Biskra (Algeria) Although Kleinschmidt already included saharae in his overview in 1907, it was removed again in the correction, partly because its description was based on only two skins from the collection of Professor Flückiger and the evidence was therefore very thin. Later he received a new series of skins from Flückiger who regularly visited the north of Africa on collection trips. The skins came from the Biskra region in Morocco, and to the south of it.

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On that basis, he decided that this saharae deserved the status of a separate subspecies. The name saharae undoubtedly refers to the geographic distribution area. 12. Athene noctua lilith (Hartert 1913) Sinai, north of the Arabian Peninsula, Jordan, Central Syria to southeast Turkey and Iraq Type locality: Deir ez-Zor by Euphrat (Syria) Athene noctua lilith was first described by the German ornithologist Ernst Hartert. For almost 40 years Hartert was curator of the Zoological Museum in Tring. The museum belonged to Lord Lionel Walter Rothschild, of the famous and wealthy Rothschild banking family. With the help of the family capital he was able to realize his childhood dream on the family estate and set up his own museum. The museum contains the largest collection of stuffed animals in the world. Ernst Hartert will have regularly sat next to him, discussing the content of the museum magazine Novitates Zoologicae that they published together for 35 years. In the years 1910–1922 he wrote the three volumes of Die Vögel der Paläarktischen Fauna: Systematisch Übersicht der in Europa, Nord-Asien und der Mittelmeerregion forkommenden Vögel, including the Little Owl. He distinguished nine subspecies, including lilith as a new subspecies (novum). Unfortunately, he did not explain the reason why he chose the name lilith. Given the region in which the subspecies occurs, however, we may assume that it refers to the female figure Lilith who appears in both (pre-) Babylonian and Hebrew mythology and writings. In the former, Lilith was a storm or night demon. The name would mean “night” in proto-Semitic (Carvalho 2009). She was the wandering spirit of those who died prematurely who had not yet been able to fulfill their destiny in life (Broekema 2014). Lilith was part of a group of four like-minded people who haunted at night and took pleasure in assaulting sleeping men. However, in some Hebrew sources, she was Adam’s first wife. Because she refused to submit to him, she left him. She is depicted, together with two lions and two owls, in the famous Burney relief, which is dated between 1800 and 1750 BC (Broekema 2014). 13. Athene noctua ludlowi (Baker 1926) south and east of the Tibetan Plateau (Ladakh, Nepal, Western Sichuan) Type locality: Rhamtso Lake in Tibet (China) Edward Charles Stuart Baker was an English police officer who spent most of his career in India. In his spare time he studied and collected birds. His estate also contained some 50 000 eggs from Indian birds. His most important contributions to ornithology were the eight volumes of The Fauna of British India, including Ceylon and Burma. Birds. The 1926 Bulletin of the British Ornithologists Club mentions his submission of the descriptions of subspecies of four oriental owls, including a Little Owl. The subspecies ludlowi is named after Frank Ludlow, an English officer who was stationed as a naturalist in India and for a time in the Tibetan capital Lhasa. At the time, he collected about 7000 birds, all of which are now kept in the British Museum, including a specimen of the newly (novum) described subspecies ludlowi, 10-12-1923 shot at Rhamtso Lake in Tibet. Baker notes that although the subspecies closely resembles

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3.3 Discovery of the Subspecies

plumipes (which also occurs in China), it is distinctively larger (wing 160–165 mm for plumipes and 169–173 mm for ludlowi). 14. Athene noctua impasta (Bangs and Peters 1928) northeast Qinghai, southwest Gansu. Type locality: Lake Kokonor (China) Outram Bangs was an American zoologist. Together with James Lee Peters, curator of Harvard University’s Museum of Comparative Zoology and president of The American Ornithologists’ Union (Wetmore 1957), he described in the museum bulletin the collection of John F. Rock during his journey westward to Kansu (China) and eastern Tibet. Peter’s most important ornithological achievement was the publication of the Check-list of Birds of the World, better known as Peters’s check-list. In part 4, among other things, owls are discussed and the Little Owl with 17 subspecies is described. Born in Vienna, later naturalized as an American, Joseph F. Rock was a widely qualified scientist. He was proficient in anthropology, botany and linguistics. He also practiced the crafts of filmmaker, photographer, explorer and author. At 16 it seems he already spoke Arabic and Mandarin. From 1924 to 1927, he led an expedition through western China and Tibet on behalf of Harvard University to collect plants and animals for the Arnold Arboretum and Museum of Comparative Zoology. During that voyage – in September 1925 – he caught an adult female Little Owl at Lake Kokonor (the Mongolian name for Lake Qinghai in today’s Qinghai province), at an altitude of 3261 m. It looked a bit like plumipes, but deviated from it because of its dark color. He collected two more, a female and a doubtful case that he considered somewhat intermediate between plumipes and impasta (Bangs and Peters 1928). While Vaurie (1960) had some doubts on the representativeness of the small sample to describe the subspecies, some more evidence for its relevance has been obtained recently. Lei et al. (1997) studied the distribution, habitat and clinal variations of the subspecies of the Little Owl in China, confirming impasta as being distinctively intermediate between ludlowi and plumipes in body coloration, as well as in body size and claw length. The morphological arguments for considering it as a subspecies were confirmed genetically by Qu et al. (2002). The results confirmed A. n. impasta and A. n. plumipes as two distinctive subspecies rather than synonymous. The name impasta comes from the Latin impastus, which means not fed, hungry (Jobling in Del Hoyo 2016).

3.3.3 Original Descriptions of Subspecies The original descriptions of the 14 subspecies are presented in their original language and translated into English. The description by Hartert (1913) can be considered as the first formal morphological description of the nominate form noctua. [ATHENE NOCTUA NOCTUA] SCOPOLI (1769) [LATIN] 15. STRIX NOCTUA. DIAGN. Pallide rufa, fuscisque maculis longitudinaliter variegata. Irides flavae. In M. p. Carnoliae indigena, et in sylvis circa Labacum copiosa. Statura Colombae. 35 https://doi.org/10.1017/9781009103725.006 Published online by Cambridge University Press

Chapter 3: Fossil Evidence, Taxonomy and Genetics

17. STRIX PASSERINA. Strix capite laevi, remigibus albis : maculis quinque ordinum, Linn. l.c.n.12 Kram. L.c.n. 6. Ital. Civetta Germ. Tschiavitl, Hauseule, Stockeule, Käuzlein. DIAGN. Inservit aucupio inprimis Sylviarum. Nidificat in caminis. [ATHENE NOCTUA NOCTUA] SCOPOLI (1769) [ENGLISH] [15. Pale red spots, facial disk variegated lengthwise. Iris yellow. Native to M. p. Carnolia and woods around Ljubljana. Pigeon-like stature. 17. Used for bird catching, particularly passerines? Breeds in chimneys.] [ATHENE NOCTUA NOCTUA] HARTERT (1913) [GERMAN] ♂ ♀ ad. Oberseite erdbraun, wie Sepia oder Ridgways ‘bistre’, Oberkopf mit längeren oder mehr rundlicheren, kürzeren Schaftflecken, die die Spitze nicht erreichen und weiß mit einem rahmfarbenen Anfluge. Federn an Nacken und Hinterhals rahmweiß mit grauen Wurzeln und breiten, erdigbraunen Rändern, so dass ein deutliches, breites, weißes Flankenband entsteht angelegt, auf der übrigen Oberseite sind die weißlichen Flares kleiner und oft doppelt, mehr oder minder durch die breiten Säume verdeckt, aber an den Skapularen und größeren Flügeldecken aber treten sie bedeutend mehr hervor; sie sind dort groß und die Flecke der beiden Fahnen bilden zusammen einen großen Fleck. Schwingen tiefbraun, Außenfahnen mit rahmfarbenen Flecken, Innenfahnen mit weißlichen, den Schaft nicht erreichenden Querbinden, außerdem ein an den Armschwingen deutlicherer, beziehungsweise breiterer, weißlichen Spitzensäum. Steuerfedern wie der Rücken, mit schmalem Endsaum und 4, selten 5 hell rahmfarbenen Querbinden, die mitunter am Schaft nicht gansz susammenhëngend sind. Kinn und Vorderhals weiß, durch ein braunes Fleckenban voneinander getrennt; übrige Unterseite weiß mit rahmfarbenem Anflug und dunkel- oder erdbraunen Flecken, meist in Gestalt von in der Mitte etwas schmaleren Längsflecken, an den Brustseiten rundlicher werdend. Analgegend und Unterschwanzdecken ungefleckt, letztere oft mit braunen Schäften oder ebensolchen aber nur sehr schmalen Streifen. Laufbefiederung rahmweiß, Unterflügeldecken ebenso, aber mit einigen braunen Flecken. Iris gelb. Schnabel wachsgelb, an der Wurzel grünlich. [ATHENE NOCTUA NOCTUA] HARTERT (1913) [ENGLISH] [Upper side earth brown, like sepia or Ridgways “bistre,” upper head with longer or more rounded, shorter shaft spots that do not reach the tip and are white with a cream-colored tint. Feathers on the neck and back of the neck creamy white, with gray roots and broad, earthy brown edges, so that a distinct, wide, white flank band is created. On the rest of the upper side the whitish bands are smaller and often double, covering the broad edges more or less thickly, but they stand out much more on the scapula and larger elytra; they are big there and the spots of the two bands together form a big spot. Wings deep brown, external flags with cream-colored flecks, inner flags with whitish cross-bands that do not reach the shaft, and a more distinct or brighter, whitish lace border on the wings. Back feathers with 36 https://doi.org/10.1017/9781009103725.006 Published online by Cambridge University Press

3.3 Discovery of the Subspecies

a narrow bottom edge and four, rarely five light cream-colored transverse bands, which are sometimes not completely connected on the shaft. The chin and front neck are white, separated from one another by a brown band, the rest of the underside is white with creamcolored patches and dark or earth-brown patches, mostly in the form of slightly pale longitudinal patches in the middle, becoming more rounded on the chest. Anal area and under the tail unspotted, the latter often with brown shafts or similar but only very narrow stripes. Fletching creamy white, underwing coverts as well, but with a few brown spots. Iris yellow. Bill wax yellow, greenish at the root.] [ATHENE NOCTUA BACTRIANA] BLYTH (1847) [ENGLISH] Athene bactrianus, mihi, n.s. ? [Strix persica (?) Nouv. Dict. d’Hist. Nat., VII, 26.] Length about 9 inches; of wing 6.25 inches, and tail 3.5 inches: tarse 1.25 inch. Plumage of the upper parts somewhat rufescent clay-brown, with large white spots on the features, more or less concealed, and wholly so on those of the middle of the back: coronal feathers with whitish streaks: face white; some of the radiating feathers on the sides of the beak terminating in black vibrissae: chin, throat, lower tail-coverts, and the tibial and tarsal plumes, white also the fore-part of the under-surface of the wing: a longitudinal broad streak on each feather of the breast and abdomen: on the hindneck, the white so predominates upon the feathers as to give the appearance of a half-collar: the great wing-feathers have broad incomplete pale bands, disposed alternately on their two webs; and the middle tail feathers have a double row of semi-alternating pale spots, passing into dull bands on the outer tail feathers: beak (in the dry specimen) whitish; and claws pale horn-color. Common upon the rocks and ruins of old Candahar. [ATHENE NOCTUA GLAUX] SAVIGNY (1809) [FRENCH] ORDRE 1er, FAMILLE 3, LES CHOUETTES, 287 Jambes à plumes courtes. Les plumes de tout le corps molles et douces au toucher. Genre XIII. NOCTUA. Caractères principaux. Bec épais, très court, brusquement incliné, peu comprimé, convexe dessous; cire trèsrenflée sur les narines et comme gibbeuse de chaque côté; narines écartées, très petites, parfaitement rondes, tournées en devant; mandibule inférieure ayant échancrures marginales vers le bout. Langue ovale, épaisse, pourvue de deux côtes en dessous, très obtuse. Tarses laineux de toutes parts. Doigts velus jusqu’à la base des dernières phalanges. Ongle intermédiaire sans crénelures. Caractères accessoires. Ailes peux pointues, dépassée par la queue. Quatre à cinq rémiges légèrement échancrées; la première assez courte, la troisième la plus longue.

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Queue égale. Cercles périopthalmiques médiocres et peu réguliers. Oreilles externes petites, rondes et dénuées d’opercules. Tête sans aigrettes. Espèce 22. NOCTUA GLAUX, LA CHEVÊCHE. (v) NOCTUA iridibus pallidé flavis; abdomine maculato; gula alba [ATHENE NOCTUA GLAUX] SAVIGNY (1809) [ENGLISH] [Main Characters Beak thick, very short, sharply inclined, slightly compressed, convex underneath; wax very swollen on the nostrils and as a gibbous on each side; nostrils wide apart, very small, perfectly round, turned forward; lower mandible with marginal notches towards the end. Tongue oval, thick, with two ribs underneath, very obtuse. Woolly tarsi on all sides. Toes feathered to the base of the last knuckles. Intermediate nail without crenellations. Accessory Characters Wings little pointed, exceeded by the tail. Four to five slightly indented flight feathers; the first rather short, the third the longest. Equal tail. Poor and irregular periopthalmic circles. Outer ears small, round and without operculum. Head without crags. NOCTUA Iris pale yellow; spotted belly; white throat] [ATHENE NOCTUA IMPASTA] BANGS AND PETERS (1928) [ENGLISH] ATHENE NOCTUA IMPASTA subsp. Nov. Type. – Adult female, No. 239416Mus. Comp. zool.; grass country south of Lake Kokonor, 10 700 feet; collected September 1925 by Joseph F. Rock (orig. no. 408). Characters. – Similar to A. n. plumipes (Athene plumipes Swinh., P.Z.S. 1870, p.448 Shato, north China) in having feathered toes, but much darker; pale markings on the top of the head linear rather than guttate; light tail bands interrupted; markings underneath darker and more extensive.

Number

Sex

Wing

Tail

Tarsus

239416 239417 239418

♀ (type) ♀ ♀ (♂?)

167 168 157

108 102 91

38 34 34

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3.3 Discovery of the Subspecies

Athene noctua plumipes From Shansi 87567 87568

♀ ♀ (♂?)

166 155

92 85

34.5 35

Of the specimens of our new form listed, in addition to the type, one was secured on the grasslands at the heat of the Serchen valley (13 300 feet) three days east of Radja, 26 July 1926 and the third was taken in May 1925 in the forests covering the slopes of the mountains of Choni (9000 feet). The latter specimen as might be suspected on geographic grounds, is somewhat intermediate between impasta and plumipes. It approaches the latter in having the light tail spots almost forming bands, but tends toward the former in the extent of the streaking underneath and in having linear pale crowns-stripes – on the whole it is best placed with impasta. We have not seen Athene noctua ludlowi Stuart Baker of southern Tibet, but that form is said to be about the color of A. n. plumipes. Our new form is much darker, in fact little paler than A. noctua noctua of Europe. Our bird also comes from a region that is quite different faunally, and although we hesitated at first, we now see no course open but to name it. [ATHENE NOCTUA INDIGENA] BREHM C.L. (1855) [GERMAN] Fang der Kaüze 3)

Der Griechische Steinkauz. Athene indigena, Brm.

Er steht in der Zeichnung swischen Nr. 2 und 4 mitten inne, hat auf dem Ünterkörper sehr verwachsene Flecken, lebt in Griechenland und wandert nach Aegypten. 4) Der Südlichen Steinkauz. Athene meridionalis, Brm. (Strix meridionalis, auct. Noctua nilotica, Paul de Wrttbg.) Er ähnelt der vorhergehenden; allein sein Oberkörpfer und die Flecken des Unterkörpfers ziehen sharf ins Rostbraune. Er lebt in Aegypten und Südeuropa. [ATHENE NOCTUA INDIGENA] BREHM C.L. (1855) [ENGLISH] [3) The Greek little owl. Athene indigena, Brm. It is in the middle of the drawing between nos. 2 and 4, has very overlarge spots on the lower body, lives in Greece and migrates to Egypt. 4) The southern little owl. Athene meridionalis, Brm. (Strix meridionalis, auct. Noctua nilotica, Paul de Wrttbg.) It resembles the previous one, but his upper body and the spots on the lower body turn sharply rusty brown. He lives in Egypt and southern Europe.] [ATHENE NOCTUA LILITH] HARTERT (1913) [GERMAN] 1461. Athene (oder Carine) noctua lilith subsp. Nov. Noch bleicher, mehr sandfarben, als A. n. bactriana, auch die Flecke der Unterseite blasser und mehr röthlichgelblich, ausserdem die Zehen nur mit Borsten bedeckt, nicht

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Chapter 3: Fossil Evidence, Taxonomy and Genetics

dicht befiedert wie bei A. n. bactriana. Flügel von 12 Exemplaren 154-168 mm. – Typus: ♀ Der-ez-Zor amd Euphrat, 15. V. 1911, gesammelt von J.Aharoni, im Tring-Museum. Palästina und Mesopotamien (oberer Euphrat), und das südwestliche Persien. Untersucht wurden exemplare in den Museen von Tring und Berlin und aus Witherbys Sammlung. [ATHENE NOCTUA LILITH] HARTERT (1913) [ENGLISH] [Even paler, more sand-colored than A. n. bactriana, the spots on the underside are also paler and more reddish-yellow, moreover the toes are only covered with bristles, not densely feathered as in A. n. bactriana. Wings of 12 specimens 154–168 mm. - Type: ♀ Der-ez-Zor amd Euphrates, 15th V. 1911, collected by J. Aharoni, in the Tring Museum. Palestine and Mesopotamia (Upper Euphrates), and southwestern Persia. Examples were examined in the museums of Tring and Berlin and from Witherby’s collection.] [ATHENE NOCTUA LUDLOWI] BAKER (1926) [ENGLISH] In general color intermediate between A. n. noctua and A. n. bactriana – in fact, very similar to A. n. plumipes from Sheni, China, but decidedly bigger than that bird, which has a wing between 160 and 165 mm. The amount of feathering on the toes varies considerably, both individually and seasonally, but in winter most birds have the plumelets extending down the toes almost to the base of the claws. Colors of soft parts. Iris yellow; bill bright yellow; legs gray, soles yellow (F. M. Bailey). Measurements: 4 ♂, 2 ♀. Wing 169 to 173 mm; tail 88 to 96 mm; tarsus 31 to 32 mm; culmen 18 to 20 mm. Distribution: Tibet. A bird from the Mishmi Hills is nearest to the present race, but is smaller (wing 164 mm) and rather darker. Type in British Museaum. ♂. Dochen, Rhamtso Lake, Tibet, alt. 15 000 ft, 10.12.23. Collected by F. Ludlow, No. 40. Brit. Mus. Reg. No. 1926.11.11.1. [ATHENE NOCTUA ORIENTALIS] SEVERETZOV (1873) [RUSSIAN] 38. Athene orientalis от Европейской A. noctua отличается тем, что бурый цвет последней A.orientalis гораздо бледнее, переходит в серо-рыжеватый с желтоватым оттенком как A. noctua meridionalis, от которой A. orientalis отличается густым оперением пальцев, кроме ногтевого сустава. Пальцы оперены также густо, как у A. (Nyctale) Tengmalmi, но кроме своего темного цвета, A. Tengmalmi отличается ушными отверстиями, полулунными и гирокими, во всю вышину черепа, между тем как у A.orientalis ушное отверстие овально и гораздо меньше, в пол-черепа, как у A.noctua. По Киргизски A.orientalis ай-хай, по крику: тоэе бай-кыль (богатая девица). По соединению этих признаков, светлого цвета с пушистыми пальцами, A. orientalis я считаю не видоизменением, а особым видом. [ATHENE NOCTUA ORIENTALIS] SEVERETZOV (1873) [ENGLISH] [38. Athene orientalis is distinct from the European A. noctua by the fact that the brown color in the latter is darker. A. Tengmalmi and A. orientalis are more pale, transforming

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3.3 Discovery of the Subspecies

into gray-russet with a yellowish tint as A. noctua meridionalis, from which A. orientalis is distinguished by the dense feathering of the toes, excluding the nail joint. The toes are feathered more densely, like A. (Nyctale) Tengmalmi, apart from the dark color. A. Tengmalmi differs by the ear hole, semi-moon and wide, the entire height (upper part) of the skull, whereas in A. orientalis the ear hole is oval and much smaller, half of the skull, like A. noctua. In the Kyrghyz language A. orientalis is ai-khai, from its call; also bai-kyz (rich young lady). By combining these observations, the light color with feathered toes, I consider A. orientalis not as a species variation, but as a separate species.] [ATHENE NOCTUA PLUMIPES] SWINHOE (1870) [ENGLISH] A. bactriana (Blyth) of Thibet, by its short tarse covered with long down, and by its wellclothed toes. I propose to distinguish it as the ATHENE PLUMIPES, sp. Nov. Throat white, the white extending in crescent-form up each cheek in rear of earcoverts (the lower white neck-ring of A. noctua is wanting); lores, round eye, and middle of belly also pure white; upper parts light reddish brown, with drops of reddish white on the head, and marked and spotted much as in A. noctua; underparts, leg- and feetfeathers cream-color, on the breast and flanks broadly streaked with reddish brown, like A. glaux (A. noctua being spotted with white on a dark ground and wanting the white on the center of the belly); bill yellow tinged with green; irides light yellow; claws blackish brown. Length about 8.5 inches; wing 6.2, of similar-proportioned quills to those of A. noctua; tail 3.6, of 12 equal feathers; tarse to base of hind toe 0.85, densely clothed with down-like feathers, 0.65 long; feet covered with shorter hair-like feathers, just showing scales at the end of toes; soles bare and yellow. [ATHENE NOCTUA SARDA] KLEINSCHMIDT (1907) [GERMAN] 9. Sardinien. Strix Athene sarda form. Nov. 3 Stück augenblicklich in meinen Händen. Ich have aber mehr gesehen. Dem mitteldeutschen Vogel ähnlich, im Herbst bisweilen dunker, im Sommer bisweilen lichter als Mitteldeutschland und Rhein. Unterscheidet sich durch die engere Zeichnung. Der Schwanze eng und schmal weisslicht gebändert. Am deutlichsten wird der Unterschied an den Schulterfedern. Die weissen Querflacken sind hier sehr klein und werden von einem dunkeln Schaftstrich längs der Federmitte geteilt. Das sardinische Käuzchen bildet eine hübsche Parallel zu Falco Peregrinus brookei. [ATHENE NOCTUA SARDA] KLEINSCHMIDT (1907) [ENGLISH] [Three pieces currently in my hands. But I’ve seen more. Similar to the Central German bird, sometimes darker in autumn, sometimes lighter in summer than Central Germany and the Rhine. Differs in the narrower markings. The tail is narrowly banded with white. The difference is most evident on the shoulder feathers. The white transverse bands are very small here and are divided by a dark line along the middle of the feather. The Sardinian owl forms a nice parallel to Falco Peregrinus brookei.]

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Chapter 3: Fossil Evidence, Taxonomy and Genetics

[ATHENE NOCTUA SAHARAE] KLEINSCHMIDT (1909) [GERMAN] 2. Strix saharae Formenkreis Strix Athene. Terra typica Algerische Sahara. In Falco 1907 p. 66 No. 15 war obiger Name schon gedruckt. Er wurde bei der Korrekty wieder gestrichen, weil dat Vorhandensein von nur zwei Stücken einerseits und die rote Abbildung der Strix numida (Lavaillant) die Benennung bedenklich machten. Nun hat mir aber Herr Flückiger noch eine ganze Serie zugesandt, die er auf seiner ersten Reise bei Biskra und weiter südlich gesammelt hat. Das Flügelmaximum erhöht sich auf 16,3 cm. Sonst bleibt es bei der an der citierten Stelle gegebenen Charakteristik. Typus von Moulaina. Verbreitung von Biskra südlich (vielleicht bis ins südliche Tunesien). Strix numida ist eine rote Phase der Mittle-Algerische Form, wenn man eine genaue Deutung dieser Abbildung überhaupt wagen will. [ATHENE NOCTUA SAHARAE] KLEINSCHMIDT (1909) [ENGLISH] [Form circle Strix Athene. Terra typica Algerian Sahara. In Falco 1907 p. 66 No. 15 the above name was already printed. It was deleted from the Korrekty because of the presence of only two pieces on the one hand and the red image of the Strix numida (Lavaillant) made the name questionable. But now Mr. Flückiger has sent me a whole series that he collected on his first trip to Biskra and further south. The wing maximum increases to 16.3 cm. Otherwise the characteristics given in the quoted passage remain. Type of Moulaina. Distribution of Biskra south (perhaps as far as southern Tunisia). Strix numida is a red morph of the Middle Algerian form, if one dares to interpret this figure at all.] [ATHENE NOCTUA SOMALIENSIS] REICHNOW (1904) [GERMAN] Bd. I Seite 671: 553a. Athene spilogaster somaliensis Rchw. Athene noctua spilogaster Erl. J. O. 1904, 238. Im Somalilande scheint eine von der abessinischen A. Spilogaster abweichende Form vorzukommen: Flügel und Schwanz kürzer; Braun der Oberseite dunkler; Oberkoph einfarbig oder weis gefleckt, aber nicht schmal gesrichelt; braune Strichelng der Unteseite dunkler. Lg. etwa 160-180, Fl. 130-140, Schw. 60-70, Schn. v. d. Wachsh. 12-13, L. 26-28 mm. [ATHENE NOCTUA SOMALIENSIS] REICHNOW (1904) [ENGLISH] [In Somaliland there seems to be a form deviating from the Abyssinian A. Spilogaster: wings and tail shorter; top darker brown; top of head monochrome or spotted white, but not narrowly dashed; brown dashes on the underside darker.] [ATHENE NOCTUA SPILOGASTRA] VON HEUGLIN (1869) [LATIN] Nr. 84. Noctua spilogastra. (Tab. IV.) Athene spilogastra, Heugl. In Cab. Journ. 1863. P. 15. – A. troglodytica, Hartl. M.S. ♀ Supra pallide et dilute rufescente-fumosa, ex albido guttatim et fasciatim varia, colore albido fulvescente-lavato; rectricibus albidis, fasciis 6-7. Rufescente-fumosis; facie, pectore postico et abdomine albidis, vix fulvescente-lavatis et striolis obsoletes

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rarioribus subrufescentibus; pectore superior eodem colore vario; tarsis antice plumosis albis; pilis digitos supra obtegentibus, setoris, albidis; subalaribus omnino albidis; rostro flavido; ceromate et unquibus brevissimis nigricante-corneis; iride flava; orbitis nudis nigricantibus; digitis incarnate-plumbeis; long. tot. 7”. 6’’’. – rostr. a fr. 7.5-8’’’. – al. 5”5”.1’’’. – caud. 2”.9’’’-3”. tars. 1”-1”.2.5’’’. – dig. med. c. u. vix 12’’’. – halluces c. u. 5.75’’’. – caudae apice alas superante 4-5’’’. [ATHENE NOCTUA SPILOGASTRA] VON HEUGLIN (1869) [ENGLISH] [♀ Above pale and faintly rufescent-smoky, variable whitish spots and streaks of a yellowish-washed white color; whitish tail feathers with six to seven bands. Rufousashy; the face, the chest, and the abdomen are whitish, scarcely washed with a yellowish shade, with worn-out and faint subrufous streaks; the upper part of the breast is of the same variable color; the tarsi are white feathered in front; the toes have bristly, whitish hairs above; feathers under the wing are completely white; beak yellow; cere with few short blackish bristles; iris yellow; orbital ring blackish; incarnate-lead fingers; Measurements: total length 7”. 6’’’. – beak to front 7.5-8’’’. - wing 5’’’-5”.1’’’. – tail 2’’.9’’’3’’. tarsi 1’’-1’’.2.5’’’. – middle toe 1 indicates that the individual has above-average fitness, while a fitness index value 30 days) caused the difference between the estimates from the two models. Because the model for wing length measurements 30) but no significant differences for A. n. sarda, A. n. indigena, A. n. noctua nor A. n. vidalii.

4.8.6 Bill Size The size of the bill measured between the tip of the bill and the start of the cere (culmen length) (Figure 4.24) varies between 11.9 and 12.4 mm. Table S4.3 illustrates the comparison of bill lengths of male and female Little Owls measured between the tip of the bill and the start of the cere. ANOVA tests comparing male and female bill size of stuffed birds from Pellegrino et al. (2020) (Table 4.6) only yield sufficiently large sample sizes (n > 30) and significant differences for A. n. vidalii (females 0.523 mm smaller bill than males; p = 0.03) and A. n. noctua (females 0.527 mm smaller bill than males; p = 0.013) but not for A. n. sarda or A. n. indigena. All bill sizes were measured by the same person with a calliper to the nearest 0.1 mm (Pellegrino et al. 2020).

4.8.7 Tarsus Length The length of the tarsus (Figure 4.25) shows significant differences between the subspecies (Table S4.4). The smallest measures were observed in birds from Cyprus (males 30.0 mm; females 30.3 mm), which were, on average, 20% smaller than the birds measured in Nordrhein-Westphalia (Germany) (males 36.7 mm; females 39.4 mm)

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Table 4.5 Comparison of tail lengths of female and male Little Owls Female Tail

Subspecies

Mean

n

Min

Max

SD

Q25

Median Q75

1 2 3 4 5 6 7 8 9 10 11

A. A. A. A. A. A. A. A. A. A. A.

79.33 73.71 75.42 75.00 76.04 – 79.00 74.58 63.50 – 72.77

3 7 12 2 26 – 2 19 2 – 30 103

76.00 70.00 72.00 72.00 69.00 – 73.00 68.00 62.00 – 68.00

83.00 76.00 79.00 78.00 85.00 – 85.00 78.00 65.00 – 79.00

3.51 2.75 2.07 4.24 3.75 – 8.49 2.97 2.12 – 2.98

76.00 70.00 73.50 72.00 73.00 – 73.00 72.00 62.00 – 71.00

79.00 75.00 76.00 75.00 75.00 – 79.00 75.00 63.50 – 73.00

n. n. n. n. n. n. n. n. n. n. n.

bactriana glaux indigena lilith noctua plumipes saharae sarda somaliensis spilogastra vidalii

83.00 76.00 77.00 78.00 78.00 – 85.00 77.00 65.00 – 74.00

Male Tail

Subspecies

Mean

n

Min

Max

SD

Q25

Median Q75

1 2 3 4 5 6 7 8 9 10 11

A. A. A. A. A. A. A. A. A. A. A.

78.14 73.00 76.00 76.00 75.54 82.00 73.60 75.38 63.50 72.00 72.61

7 10 24 5 28 2 5 13 2 1 46 143

74.00 70.00 71.00 72.00 68.00 82.00 71.00 72.00 61.00 72.00 68.00

84.00 76.00 83.00 80.00 90.00 82.00 75.00 78.00 66.00 72.00 83.00

3.34 2.36 3.15 3.08 3.89 0.00 1.67 1.76 3.54 – 2.98

75.00 71.00 74.00 74.00 73.00 82.00 73.00 74.00 61.00 72.00 70.00

78.00 73.50 76.00 77.00 75.00 82.00 74.00 75.00 63.50 72.00 72.00

n. n. n. n. n. n. n. n. n. n. n.

bactriana glaux indigena lilith noctua plumipes saharae sarda somaliensis spilogastra vidalii

80.00 75.00 79.00 77.00 77.00 82.00 75.00 77.00 66.00 72.00 74.00

ANOVA Tail

Subspecies

Difference of Averages

n

F

p

3 5 8

A. n. indigena A. n. noctua A. n. sarda

0.583 0.503 –0.806

32 50 28

0.34 0.23 0.77

0.566 0.631 0.388

After Pellegrino et al. 2020

130 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

4.9 Voice

Figure 4.24 Different bill measurements showing the (A) culmen length with cere, (B) beak depth and (C) culmen length.

(Schönn et al. 1991). The Mediterranean populations, except for the Iberian birds, have relatively small tarsi. The significant spread in average measures within the noctua subspecies shows the important local variation. The length of the tarsus was found to differ between the sexes in two German studies (Schönn et al. 1991), with females having, on average, 2.7 mm larger tarsi than males. All other studies showed a difference in length below 1 mm. ANOVA tests comparing male and female tail lengths of stuffed birds for subspecies from Pellegrino et al. (2020) (Table 4.7) only yield sufficiently large samples sizes (n >30) but no significant differences for A. n. vidalii, A. n. indigena, A. n. noctua nor A. n. sarda.

4.8.8 Other Measures Besides the most common body measures given above, Martinez et al. (2002) also reported mouth size (males: 18.33  1.6 mm; females: 19.60  0.55 mm), back claw (males: 9.67  1.7 mm; females: 9.31  1.04 mm), front claw (males: 10.72  1.10 mm; females: 11.64  0.85 mm), talon length (males: 43.56  1.40 mm; females: 43.57  1.90 mm), P8 length (males: 117.00  3.20 mm; females: 119.12  3.88 mm), wingspan (males: 557.67  11.90 mm; females: 565.64  13.15 mm) and total length (males: 234.44  11.00 mm; females: 243.57  10.29 mm).

4.9 Voice Most studies are carried out through the recording of owl vocalization in the field, with results offered as descriptions of sound spectrograms or sonagrams (Glutz Von Blotzheim and Bauer 1980, Exo 1984, 1990, Scherzinger 1988, Exo and Scherzinger

131 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

Chapter 4: Morphology and Body Characteristics

Table 4.6 Comparison of bill lengths of female and male Little Owls Female Bill

Subspecies

Mean

n

Min

Max

SD

Q25

Median Q75

1 2 3 4 5 6 7 8 9 10 11

A. A. A. A. A. A. A. A. A. A. A.

14.33 13.88 14.45 14.55 13.77 – 13.55 14.47 12.45 – 13.24

3 6 11 2 26 – 2 19 2 – 30 101

13.70 13.40 12.40 14.50 12.80 – 13.00 13.40 12.00 – 11.20

15.40 14.90 15.50 14.60 16.40 – 14.10 14.90 12.90 – 14.70

0.93 0.58 0.91 0.07 0.79 – 0.78 0.42 0.64 – 0.75

13.70 13.40 13.90 14.50 13.20 – 13.00 14.10 12.00 – 12.80

13.90 13.75 14.70 14.55 13.60 – 13.55 14.60 12.45 – 13.30

Bill

Subspecies

Mean

n

Min

Max

SD

Q25

Median Q75

1 2 3 4 5 6 7 8 9 10 11

A. A. A. A. A. A. A. A. A. A. A.

13.96 14.40 14.23 14.10 14.30 14.00 13.96 14.28 12.25 12.90 13.76

7 10 23 4 24 2 5 13 2 1 46 137

13.20 13.10 12.40 13.70 13.30 13.50 13.30 13.70 11.60 12.90 12.30

14.60 15.80 15.90 14.60 16.00 14.50 15.30 15.40 12.90 12.90 15.40

0.52 0.85 0.90 0.37 0.65 0.71 0.85 0.53 0.92 – 0.69

13.50 13.90 13.70 13.85 13.80 13.50 13.40 13.80 11.60 12.90 13.20

14.00 14.60 14.10 14.05 14.10 14.00 13.50 14.30 12.25 12.90 13.80

n. n. n. n. n. n. n. n. n. n. n.

n. n. n. n. n. n. n. n. n. n. n.

bactriana glaux indigena lilith noctua plumipes saharae sarda somaliensis spilogastra vidalii

bactriana glaux indigena lilith noctua plumipes saharae sarda somaliensis spilogastra vidalii

15.40 14.10 15.10 14.60 14.20 – 14.10 14.80 12.90 – 13.50

14.60 14.90 14.80 14.35 14.55 14.50 14.30 14.50 12.90 12.90 14.30

Bill

Subspecies

Difference of Averages

n

F

p

3 5 8 11

A. n. A. n. A. n. A. n.

0.224 –0.527 0.191 –0.523

30 46 28 72

0.46 6.59 1.31 9.782

0.504 0.013 0.262 0.003

indigena noctua sarda vidalii

After Pellegrino et al. 2020

132 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

4.9 Voice

Figure 4.25 Skeleton of Little Owl. The foot consists of toes with claws and the tarsus or tarsometatarsus. The expression “foot” is used when no specific part is referred to. Owls have four toes, three in front and one hind toe. Of the front toes the outer one may be turned backwards (as owls often do when they are roosting).

1989, Schönn et al. 1991). Exo and Scherzinger (1989) recorded 22 distinct call notes (23 including nonvocal bill snapping) (Table 4.8). Two are specific to young owls and disappear during ontogenetic development. The juvenile repertoire contains 12 defined call notes which can be summarized by three or four basic call notes. Males and females

133 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

Chapter 4: Morphology and Body Characteristics

Table 4.7 Comparison of tarsus lengths of female and male Little Owls for different subspecies Female Tarsus

Subspecies

Mean

n

Min

Max

SD

Q25

Median Q75

1 2 3 4 5 6 7 8 9 10 11

A. A. A. A. A. A. A. A. A. A. A.

34.87 32.00 33.28 31.85 34.70 – 32.40 34.39 28.05 – 36.36

3 7 12 2 26 – 2 17 2 – 30 101

33.30 30.50 30.60 31.50 31.80 – 31.70 30.60 27.90 – 33.50

37.70 34.20 34.70 32.20 38.50 – 33.10 37.50 28.20 – 39.30

2.46 1.32 1.24 0.49 1.51 – 0.99 1.99 0.21 – 1.52

33.30 30.90 32.40 31.50 33.40 – 31.70 33.30 27.90 – 35.50

33.60 32.30 33.60 31.85 34.80 – 32.40 34.30 28.05 – 36.55

n. n. n. n. n. n. n. n. n. n. n.

bactriana glaux indigena lilith noctua plumipes saharae sarda somaliensis spilogastra vidalii

37.70 32.80 34.30 32.20 35.90 – 33.10 35.60 28.20 – 37.40

Male Tarsus

Subspecies

Mean

n

Min

Max

SD

Q25

Median Q75

1 2 3 4 5 6 7 8 9 10 11

A. A. A. A. A. A. A. A. A. A. A.

31.81 33.48 33.68 34.06 35.04 32.25 33.55 34.44 28.65 28.20 35.76

7 10 24 5 26 2 4 13 2 1 45

30.10 31.30 30.30 31.80 31.70 31.80 31.20 31.90 27.80 28.20 31.50

33.60 37.10 35.50 39.10 40.70 32.70 36.40 38.80 29.50 28.20 39.70

1.25 1.93 1.43 3.03 1.85 0.64 2.18 1.79 1.20 – 1.76

30.70 31.70 32.45 31.90 34.10 31.80 32.00 33.90 27.80 28.20 34.80

31.70 33.20 34.10 32.90 34.50 32.25 33.30 34.50 28.65 28.20 35.60

n. n. n. n. n. n. n. n. n. n. n.

bactriana glaux indigena lilith noctua plumipes saharae sarda somaliensis spilogastra vidalii

32.80 34.20 34.85 34.60 35.80 32.70 35.10 34.70 29.50 28.20 36.70

ANOVA Tarsus

Subspecies

Difference of Averages

n

F

p

3 5 8 11

A. A. A. A.

–0.399 –0.338 –0.050 0.608

32 48 26 71

0.68 0.52 0.01 2.391

0.416 0.474 0.944 0.126

n. n. n. n.

indigena noctua sarda vidalii

After Pellegrino et al. 2020

134 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

4.9 Voice

Table 4.8 Different calls of Little Owls according to age and sex Relative volume Contact calls Feeding call

1 5

Feeding Feeding Feeding Feeding

5 5 5 5

call call call call

Advertising calls

7

Advertising calls Advertising calls Advertising calls Advertising calls Advertising calls Advertising calls Enemy call and defense Enemy call and defense

7 7 7 7 7 7 6 6

Enemy call and defense

6

Enemy call and defense

6

Enemy call and defense Enemy call and defense Enemy call and defense Intra-specific aggression Intra-specific aggression Intra-specific aggression Intra-specific aggression Intra-specific aggression Intra-specific aggression Song Song

6 6 6 6 6 6 6 6 6 2 2

Sound

Juveniles Females

Males

Contact call Begging-calls juvenile Begging snoring Feeding call Luring/tempting Feeding twittering Begging-calls adult Begging snoring Luring/tempting Chugging Nest showing Yelping Copulation call Alarm call Chattering/ cackling Peeping/ cheeping juvenile Defence screeching Chirping Hissing/blowing Bill snapping Trembling Peeping Excitement calls Aggressive calls Whispering calls Copulation call Song, ordinary Glissando song

x x

x

x

x x X

(x) x

x

x

Total

x (x)

X x ?

x x

x x X ? X x x

x

x

?

x X (x X x x

x ? x

x ? x)

x x ? x

x x x x x x X

x x x x

?

x

12

15

15

Brackets indicate uncertain assignment. X indicates gender- or juvenile-specific call. After Exo and Scherzinger 1989

135 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

Chapter 4: Morphology and Body Characteristics

(a)

Hooting call Frequency (kHz)

6 4.5 3 1.5 0 1.5

3 Time (s)

Chewing call

(b) Frequency (kHz) 12 9 6 3 0

1

4 Time (s)

Figure 4.26 (a) Hooting or “guhk” call of male Little Owl; (b) Chewing or “miaw” call of male Little Owl (after Hardouin 2006).

each have 15 call notes out of a total of 20 altogether. Only three for the male and two for the female are sex-specific. The final repertoire includes 40 acoustic signals with mixtures and combinations. The most common are indicated here and are based mainly on Exo and Scherzinger (1989). Most typical calls are the territorial hooting or “guhk” call and the intra-specific excitement chewing or “miaw” call (Figure 4.26). A comparative study of the vocalization repertoires within the genus Athene (Scherzinger 1988) showed a strong similarity of calls among the Little Owl Athene noctua, Spotted Owlet Athene brama and the Burrowing Owl Athene cunicularia. This study supported the placement of the Burrowing Owl in the genus Athene.

4.9.1 Calls of Adults Song (Cramp 1985, Exo and Scherzinger 1989), Guhk (Exo 1984) or Hoot (Hardouin 2006). This is the primary call used in pair formation and territorial defense. It is produced by both male and female adult owls (Exo 1984). The use of this call for census work, aiming at exact population estimates (Exo and Hennes 1978a) rather than

136 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

4.9 Voice

Figure 4.27 Territorial song of Little Owls: (a) female song, (b) male song I and II short calls; III Glissando Song of up to one second with increasing frequency (after Exo and Scherzinger 1989).

determining Little Owl presence, should pay special attention to “guhk”-like female calls (Exo 1984). The hooting call sounds like “goooek,” a loud, questioning “huui” (Haverschmidt 1946) or “ghu(k),” sometimes given in a crescendo series; towards the end of these series it changes to an excited “guiau,” or “kwiau” and ends abruptly with a shrill “hoo-ee,” or “miju” (Haverschmidt 1946, Glutz Von Blotzneim and Bauer 1980, Exo and Scherzinger 1989). The female’s call is shorter than the male’s and the tone is generally higher in pitch (Figure 4.27). Most calls are louder and clearer when given by the male and repeated monotonously in a varied group of notes, while the notes occur singly when uttered by the female (Exo 1984). During the main time of courtship the male repeats the “guhk” call, often for several minutes, whereas for females spacing between the notes is irregular and the number of calls given in a session variable between three and five, or even one (Exo 1984). Typical for the male calls is the steep frequency increase at the beginning. The basic tone of the call is mostly between 0.4 and 0.5 kHz at the start, rather constant or slightly increasing in the middle between 0.7 and 1.3 kHz. In contrast to the opening and middle sections, the end of the call is often less pure in terms of sound with both lower and higher frequencies up to 2.2 kHz, but mostly limited to 2 kHz. Female hoots are mostly above 0.5 kHz, ranging from 0.6 to 1.1 kHz in the middle part. The hoots have an average length of 0.58  0.10 s and 0.36  0.07 s for males and females, respectively (Exo 1984). The basic monosyllabic form of the territorial song can be rather variable and is described in different ways as a melanchonic “kiiu” (Mikkola 1983), a nasal increasing “uuhg” (Kehrer 1972), a clear “üü” (Stadler 1945), a rifled “ghuk” (Kleinschmidt 1934), an interrogative “guhg” (Bergmann and Helb 1982), an interrogative “ui,””huu” or “huui” as a mating call (Haverschmidt 1939, 1946). The number of calls by males varies according to the excitement of the bird between 12 and 20 per minute (Bergmann and Helb 1982). Males can sing for up to 20 minutes, while females utter a maximum of five calls (Exo 1984). During the courtship, duets occur. Simultaneous hooting of both partners or neighboring owls can lead to aggressive calls.

137 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

Chapter 4: Morphology and Body Characteristics

Figure 4.28 Comparison of the six most abundant “Ghuk” types from (a) northwest German and (b) eastern English male Little Owls. I. Basic form with characteristic roughly pressed final element. II. Basic form with a constant frequency final element. III. Basic shape with high-pitched final element. IV. Song with frequency jump in the 1st element part. V. Singing with frequency jump in the 2nd element part. VI. Transition to “aggressive singing.”

The glissando song sounds more like a whisle like “ghuui” or “gluui” and “üüüü” (Stadler 1945) or up to three syllabic calls like “goojhüi” (Exo in Schönn et al. 1991). Despite all the variability, the basic structure of the typical courtship call is always retained. A male can utter both simple “uuu” or ““gjuu” syllables, as well as nasal highdrawn “gjuüi” or long glissando syllables whose continual rise in frequency sometimes breaks off with an almost clicking element. Females lack the glissando song completely. Sonagrams of territorial songs of male Little Owls were studied by Exo (1990) in eastern England and compared with songs of birds from northwest Germany. The basic repertoire is almost the same in both populations, with the same syllable types and characteristics (Figure 4.28); the different syllable types occur in similar frequencies of occurrence (Chi-square test of frequencies nonsignificant). Population-specific syllables were not observed. A detailed analysis of the syllable structure of the different call notes showed that most notes of Little Owls from eastern England last significantly longer than of birds from northwest Germany. Furthermore, the pitch was higher in English Little Owls than in German conspecifics. The differences might indicate an actual genetic evolution due to a limited population density and the entire isolation from the continental populations supporting the local evolution of vocalizations. The Excitement Call is variable and described as “jau,” “mija,” “kwiau,” “miji,” “iwidd” and “kuwitt”(Exo and Scherzinger 1989). This “kiew” (Cramp 1985), “miau” (Exo in Schönn et al. 1991) or chewing call (Hardouin 2006) is the most commonly given. It is a clear “(k)weew,” “huu” or “gwauu”; a sharp, complaining, “kee-ew”; repeated irregularly. It is used in many cases of social contact, such as mating, feeding young, sometimes at the end of the ordinary song during courtship behavior, during copulation and nest-showing, or during disturbance at the nest site, occurrence of predators (e.g., feral cats) and territoriality. The final shrill call “kuwitt”can be confused with the call of a female Tawny Owl, Strix aluco (Bettmann 1951, Haller 1951, Runte 1951, Ammersbach 1952). This is a fast call that has been recorded at 28–36 calls/min

138 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

4.9 Voice

Figure 4.29 Excitement calls of Little Owls: I single “jau,” II strong “jau,” III “mija,” IV “mlijau,” V “mijau,” VI “mlji.jau” (after Exo and Scherzinger 1989).

(Glutz Von Blotzheim and Bauer 1980). It is mainly given in association with copulation and other aspects of heterosexual behavior, but also is given in fights between rivals. The basic frequency of excitement calls ranges between 0.8 and 1.8 kHz. The loudest sounds are mostly produced for the heighest frequencies. Repeats can be as frequent as 20–30 calls per minute. The variation in excitement call is substantial (Figure 4.29), with the shrillness going up with increasing arousal. When the excitement goes up, the syllables and intervals shorten, while frequencies rise and sounds become clearer and sharper (Exo 1987). The bill is mostly wide open during the calls. These calls are regularly combined with other calls, yielding multisyllabic sounds like “guiau(u)” in combination with hooting, “go-go jau” in combination with chugging, one to four syllables “gho-cho-cho-guau” in combination with begging or in combination with cackling/luring such as “gwju,” “guau” or “guoau.” The variations yield many different descriptions and spelling, e.g., “giou” (Stadler 1932), “whirrou” (Mikkola 1983), Lapwing-like “iwidd” (Stadler 1945), “kiut” or “kuwitt” (Kleinschmidt 1934). Excitement calls are mostly single or in longer series broadcasted from exposed perches or in flight. A special sequence of excitement calls leads to aggressive calls, while territorial song has crescendo to shrill calls. Such compilations sum up to 60 calls and are uttered with breaks of several minutes and repeated up to 50 times (Illner in Glutz Von Blotzheim and Bauer 1980). Excitement calls always precede the aggressive song and increase in speed, volume and aggressive arousal. Excitement and aggressive calls are very variable and frequently combined with other calls. Robb and The Sound Approach (2015) illustrate the “cu-cu-miau” sequence as a combination of two alarm calls followed by an excitement call. Similar to this, we found many different combinations in the xeno-canto database of recordings, including the reverse order of “miau-cu-cu,” amongst other combinations. A check of 300 vidalii, noctua and indigena recordings at www.xeno-canto.org showed that the number of alarm calls varies between none and three before and after the “miau”-call (Table 4.9). A verification by Exo (personal communication) of the most unusual combinations indicated that amongst the different subspecies, no structural differences could be observed and all the calls sounded very familiar, even the “cu-cu-miau.” Such variations were observed by Exo during his entire research of Little Owl vocalizations

139 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

Chapter 4: Morphology and Body Characteristics

Table 4.9 Little Owl recordings downloadable from www.xeno-canto.org indicating a large variation of sequences of calls across all subspecies. Xeno-canto multisyllabic excitement calls Subspecies

Recording

Country

Sequence

url

vidalii

XC584228

Belgium

miau-cu-cu

vidalii

XC584232

Belgium

miau-cu-cu

lilith

XC586495

Cyprus

cu-cu-miau

vidalii

XC543093

France

miau-cu-cu-cu

vidalii

XC581158

France

cu-cu-cu-miau

vidalii

XC632858

France

cu-miau

vidalii

France

miau

vidalii

XC640751 (same bird as XC640752) XC640752

www.xeno-canto.org/ 584228 www.xeno-canto.org/ 58432 www.xeno-canto.org/ 586495 www.xeno-canto.org/ 543093 www.xeno-canto.org/ 581158 www.xeno-canto.org/ 632858 www.xeno-canto.org/ 640751

France

cu-miau

vidalii

XC666245

France

miau-cu

vidalii

XC582853

Germany

miau-cu

noctua

XC104903

Italy

cu-cu-miau

noctua

XC130646

Italy

cu-miau

noctua

XC280410

Italy

noctua

XC303918

Italy

cu-cu-cu-cucu-cu-miau cu-cu-miau

noctua

XC76846

Italy

cu-miau

indigena

XC289312

Turkey

indigena

XC386897

Azerbaijan

cu-cu-cu-cucu-cu-miau hoot

lilith

XC329983

Cyprus

miau

140 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

www.xeno-canto.org/ 640752 www.xeno-canto.org/ 666245 www.xeno-canto.org/ 582853 www.xeno-canto.org/ 104903 www.xeno-canto.org/ 130646 www.xeno-canto.org/ 280410 www.xeno-canto.org/ 303918 www.xeno-canto.org/ 76846 www.xeno-canto.org/ 289312 www.xeno-canto.org/ 386897 www.xeno-canto.org/ 329983

4.9 Voice

Table 4.9 (cont.) Xeno-canto multisyllabic excitement calls Subspecies

Recording

Country

Sequence

url

vidalii

XC402735

Denmark

very long hoot

vidalii

XC542901

France

miau-miau

vidalii

XC563549

France

arousal

vidalii

XC579256

France

weird

vidalii

XC625972

France

hissing

vidalii

XC632855

France

miljau

vidalii

XC637312

France

alarm

vidalii

XC637939

France

male hoot

indigena

XC383820

Greece

miau

indigena

XC384037

Greece

miau

noctua

XC608765

Hungary

queck-queck

noctua

XC431705

Italy

screech

noctua

XC551298

Italy

very long miau

noctua

XC585163

Italy

begging

lilith

XC167696

Kuwait

hoot

indigena

XC379810

Greece

miau

orientalis

XC498062

Mongolia

miau

vidalii

XC565134

Netherlands

nestlings

vidalii

XC635668

Netherlands

female hoot

www.xeno-canto.org/ 402735 www.xeno-canto.org/ 542901 www.xeno-canto.org/ 563549 www.xeno-canto.org/ 579256 www.xeno-canto.org/ 625972 www.xeno-canto.org/ 632855 www.xeno-canto.org/ 637312 www.xeno-canto.org/ 637939 www.xeno-canto.org/ 383820 www.xeno-canto.org/ 384037 www.xeno-canto.org/ 608765 www.xeno-canto.org/ 431705 www.xeno-canto.org/ 551298 www.xeno-canto.org/ 585163 www.xeno-canto.org/ 167696 www.xeno-canto.org/ 379810 www.xeno-canto.org/ 498062 www.xeno-canto.org/ 565134 www.xeno-canto.org/ 635668

continues 141 https://doi.org/10.1017/9781009103725.007 Published online by Cambridge University Press

Chapter 4: Morphology and Body Characteristics

Table 4.9 (cont.) Xeno-canto multisyllabic excitement calls Subspecies

Recording

Country

Sequence

url

vidalii

XC574057

Poland

male hoot

vidalii

XC574060

Poland

kieuw

vidalii

XC200789

Portugal

miau

vidalii

XC594439

Portugal

miau

vidalii

XC628295

Portugal

kiwit

lilith

XC215633

Qatar

hoot

vidalii

XC663140

Spain

hissing

lilith

XC209241

UAE

hoot

vidalii

XC572506

UK

male hoot

vidalii

XC592428

UK

nestlings

vidalii

XC592429

UK

vidalii

XC592431

UK

female as male enters with food pair interaction

www.xeno-canto.org/ 574057 www.xeno-canto.org/ 574060 www.xeno-canto.org/ 200789 www.xeno-canto.org/ 594439 www.xeno-canto.org/ 628295 www.xeno-canto.org/ 215633 www.xeno-canto.org/ 663140 www.xeno-canto.org/ 209241 www.xeno-canto.org/ 572506 www.xeno-canto.org/ 592428 www.xeno-canto.org/ 592429

vidalii

XC592434

UK

begging

vidalii

XC592435

UK

begging

vidalii

XC592436

UK

bill snapping

vidalii

XC592437

UK

screech

vidalii

XC615449

UK

duet

indigena

XC401499

Ukraine

hoot

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www.xeno-canto.org/ 592431 www.xeno-canto.org/ 592434 www.xeno-canto.org/ 592435 www.xeno-canto.org/ 592436 www.xeno-canto.org/ 592437 www.xeno-canto.org/ 615449 www.xeno-canto.org/ 401499

4.9 Voice

with a number of variations in which the “cu-cu” can preceed or follow the “miau,” or the “cu-cu” is not heard. A first analysis of a limited sample from different countries gives the idea that one will detect these variations in all countries. So-called differences could simply be artifacts of a limited number of sequences analyzed before assuming geographical differences. Our limited unrepresentative sample size gives the idea that the concentration of “cu-cu” in front seems to be higher in Italy, but certainly not exclusively, and currently it has not been found in the samples from the Balkans (indigena) and only once in a recording from Turkey and Cyprus (indigena). So far there is no evidence to support Athene noctua vidalli being a different species compared to the other subspecies. A differentiation based upon specific variations in vocalizations alone is not conclusive and statistically not sound. Hence we see no reason why there would be the need to split A. n. vidalii from A. n. noctua, indigena, glaux, sahare and lilith based upon a three-syllabic “cu-cu-miau” (Robb and Sound Approach 2015) simply because the sample of vidalii individuals from Portugal might be too small and statistically biased to not produce this variation. The Whispering Call, similar to “shrie,” is used as a contact call. It is prominently given by the female during courtship (Glutz Von Blotzheim and Bauer 1980). Begging Calls of the female are extentions of those from juveniles, “tsiech,” “schräää” and “siej” sounds (Glutz Von Blotzheim and Bauer 1980, Exo and Scherzinger 1989). The Feeding Trill from females is used when feeding young. It is a rapid, nasal “gekgok-gok-gok,” or hoarse cackling, sometimes interrupted by “uuh” as with the “kiew” call (Glutz Von Blotzheim and Bauer 1980, Exo and Scherzinger 1989). The Nest-Showing Call of the male is similar to the “zick-zick” of the Kestrel Falco tinnunculus, or “tjuck-tjuck” of the domestic cockerel given during nest-showing; it is also occasionally given during mating (Glutz Von Blotzheim and Bauer 1980, Exo and Scherzinger 1989). The Copulation Call is a soft “oo-oo”given by birds sitting close together, before or after copulation. The female shrieks during copulation. The male often sings “goooek” before mating and sometimes during mounting (Haverschmidt 1946, Exo and Scherzinger 1989). The male also uses the “kiew” call, the excitement call and the nest showing nest-showing call. The Alarm Call is used as an alarm and given during times of anxiety and for warning. It is a loud, chattering “kek-kek” when an owl is disturbed at its nest (Haverschmidt 1946, Exo and Scherzinger 1989). Calls based on “queb”and “keck” sounds express fear; short “kja” or “kju” are given as a warning to a rival or predator; “quip” expresses anxiety; “quijep” is given as warning to young at fledging age. Snoring or screeching sounds are given in displeasure or fear (Glutz Von Blotzheim and Bauer 1980). Bill-snapping is a typical alarm noise of the Strigiformes family (Schönn et al. 1991). Little Owls can produce this sound from 10 days of age (Exo in Schönn et al. 1991). Some authors (Gooch 1940, Haverschmidt 1946) have mistakenly interpreted this sound as tongue-clicking. The alarm call (Figure 4.30) is sometimes combined with excitement calls or aggressive calls including “cu-cu-miau” or “miau-cu-cu” in most subspecies, including vidalii. An under-representation of samples from the Balkans might be the principal reason for

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Chapter 4: Morphology and Body Characteristics

Figure 4.30 Alarm call and bill-snapping sound of Little Owls: (a) Alarm call – I “kek,” II “kju.kek,” III “kau,” IV “kju.kau,” V “kju.i.pep.pep” (I, II and V: adult birds; III and IV fledged birds). (b) Bill-snapping (30-day-old juvenile birds).

the lack of such combinations. Only about half of Italian samples (noctua) produce “cucu-miau” combinations. The Hissing Call is given in threat and is often linked to the alarm call (Schönn et al. 1991). Other Calls: A squeaky “uik” is given during allopreening, which is a rare behavior (Glue and Scott 1980). A hissing or rasping sound is produced by males and females, probably in a begging or contact calling context (Glutz Von Blotzheim and Bauer 1980). A curious snoring is sometimes given by day in spring, sounding like the exhalation of person in deep sleep (Witherby et al. 1938). Owls also give various shrieking, yelping, grumbling and rasping calls (Glutz Von Blotzheim and Bauer 1980, Exo and Scherzinger 1989).

4.9.2 Calls of the Young A food-begging call is given from unhatched (still within the egg) and small young. It is a monosyllabic “psiep,” “szip,” or “srie” and a disyllabic “uiiet.” In the second week after hatching it becomes a harsh, “chsij,” “chriie” or hissing “schwo”; in the fourth week a rasping snoring like a Barn Owl Tyto alba is given. Several adult calls, e.g., “gjuu” as the “kiew” call, “kek,” snoring (alarm call) and hissing develop while the young are still in the nest or shortly afterwards. The typical territorial song is given during the first autumn (Ullrich 1973, Glutz Von Blotzheim and Bauer 1980).

4.10 Flight The flight of the Little Owl is direct, swift, easy and wave-like, very similar to a woodpecker’s flight. The owl’s wing-beats are as silent at high frequencies as they are at low ones, and have no ultrasonic noise (Thorpe and Griffin 1962) despite the fact that its leading-edge wing serrations that are one of the adaptations of owls to silent flight are less well developed than those in Barn Owls (Weger and Wagner 2016). In certain cases, in particular when hunting, Little Owls display hovering flight like Kestrels (Martin and Rollinat 1914, Malmstigen 1970, Wahlstedt 1971). The hovering takes place 2–3 m or sometimes as much as 20 m above the ground (Gyllin 1968), with the owl finally closing its wings and dropping like a stone on the prey (Gregory 1944, Tayler 1944).

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4.11 Digestive Organs

4.11 Digestive Organs In the context of a taxonomical study, the chemical composition of the uropygial gland waxes of the Little Owl was compared to those of diurnal birds of prey and confirmed that owls seem to be an isolated order (Jacob and Hoerschelmann 1984). Some data on the digestive organs were collected in Turkmenistan (Broun 1986). Therelative weight of the glandular stomach is 0.54% of the overall body weight. The relative weight of the stomach muscle is 2% and it has comparatively thin walls. The bowel is comparatively short, being 198% of the body length. There are blind appendices between the thin and thick parts of the bowel, representing 14.5% of the total length of the bowels. Histomorphological observations of the digestive apparatus showed that the third blind intestine of the Little Owl is absent and developed glands are plentiful. The muscular tunics and the glands of the duodenum and the organ of Meckel are well developed compared to those of granivorous birds (Richetti et al. 1980). A comparitive neurohistological study of the esophagus in granivorous, omnivorous and carnivorous birds showed that carnivorous birds have one remarkable development in the innervation of the esophagus, advanced compared to granivorous and omnivorous birds. The nervous plexus of the esophagus is supplied with many nervous cells and the muscularis mucosae is well developed (Costaglia et al. 1981).

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Chapter 5: Distribution, Population Estimates and Trends

Chapter Summary In this chapter, we examine aspects of distribution and population for the Little Owl over its global range which covers 78 countries. Three recent publications give an overview of population numbers and short- and long-term breeding population and breeding distribution trends for the EU28 (European Environment Agency 2021) and for continental Europe (BirdLife International 2015, Keller et al. 2020). The European Union (EU28) Red List assessments were based principally on the official data reported by EU Member States to the European Commission under Article 12 of the Birds Directive. All Member States are requested by the Birds Directive to monitor bird species and send a report every six years. This information includes population sizes and trends (short and long term) for breeding and wintering populations, as well as pressures and threats for Special Protection Area trigger species. In addition, population status and trends are assessed at the EU level. The reporting period 2006–2012 data were used by BirdLife International (2015) and Keller et al. (2020). The reporting period 2013–2018 data were used by the European Environment Agency (2021). Detailed information about the reporting under Article 12 of the Habitats Directive can be obtained from www.eionet.europa.eu/etcs/etc-bd/activities/reporting/art icle-12/. The reported data as well as the assessments of status and trends at the EU level can be visualized in the web tool http://bd.eionet.europa.eu/article12/. For the European Red List assessments outside the EU28, similar data were sourced from BirdLife Partners and other collaborating experts in other European countries and territories (BirdLife International 2015, Keller et al. 2020). Some further declining populations were observed in central European (e.g., Poland, Austria, Czech Republic, Slovakia, Slovenia) and northern European (e.g., Denmark, Estonia, Latvia) countries, stable or fluctuating populations in Mediterranean countries (e.g., Portugal, Spain, Italy, Greece, Cyprus). Positive trends, either long term or short term are observed in western European countries (e.g., Germany, Belgium, Netherlands, France, Luxembourg, Switzerland), where conservation initiatives have yielded or are starting to yield positive results. Balkan countries were not monitored in detail. Short-term trends were more positive than long-term trends.

Supplementary resources are available online at www.cambridge.org/littleowl. These include appendices as well as tables which previously appeared in the first edition (prefixed with ‘S’).

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Table 5.1 General short-/long-term trends in population numbers and distribution at different spatial scales –

=

2

5

13

1996–2018

2

6

2001–2018

2

Range

Scope

Reference

Years

Europe

Short-term population trends Short-term distribution trends Short-term population trends Long-term population trends Long-term population trends Long-term population trends Long-term distribution trends

BirdLife International 2015

1998–2012

European Environment Agency 2021 European Environment Agency 2021

EU28 EU28 Global Distribution Europe EU28 Global Distribution

+

F

X

Total

13

37

12

4

24

8

9

5

24

12

10

23

33 1

BirdLife International 2015

1973–2013

3

9

5

European Environment Agency 2021

1973–2018

2

13

12

10

–: Decrease; +: Increase; =: Stable; F: Fluctuating; U: Uncertain; X: Unknown

4

78 19

37

4

5

24

25

31

78

147

Chapter 5: Distribution, Population Estimates and Trends

Data outside the European continent were obtained from individual publications. In very general terms, all cumulative data suggest that the global distribution of the Little Owl increased in 12 countries, decreased in 10, remained unchanged in 25 and was insufficient for determination in 31 countries (Table 5.1). For population numbers, the data suggests that the number of owls increased in 12 countries, decreased in 10, remained unchanged in 23 and was insufficient for determination in 33 countries. This chapter gives a description of the global distribution and some limiting factors such as latitude and elevation, and presents maps of European population numbers and short- and long-term trends. For each country we focus on the population estimates for currently existing populations and present distribution maps when available. In Table S5.1 we give details per country on the evolution of the distribution and the population estimates. Except the countries of western and central Europe, where the Little Owl has decreased for the last 40 years due to land-use changes, the species remains common or relatively widespread in all the Mediterranean countries from southern Europe and the Middle East to North Africa and in many Asiatic republics of the former Soviet Union, where natural habitats of the Little Owl still occur. Changes in Little Owl numbers reflect the effects of regulatory factors acting on the populations (see Chapter 10). Some western European countries were able to counter the downward progressions through a professional conservation and management strategy and local volunteer actions. (For management best practices see Chapter 11.)

5.1 Distribution A map showing the rough approximation of Little Owl global distribution is given in Figure 5.1. The distribution is principally determined by the latitude, elevation, climate and land use. We discuss latitude and elevation in this chapter, while land use is discussed in relation to habitat selection in Chapter 6.

5.1.1 Latitude The species occurs in middle and lower latitudes (mainly between the 22nd and 51st parallels and at the extremes between the 9th and 56th parallels), both continental and marginally oceanic, mainly temperate, steppe and Mediterranean biotopes, but extending to boreal and tropical. While adapting to windy and rainy climates, it favors warm, even semi-arid conditions and is vulnerable to severe frosts and snow cover (Glutz Von Blotzheim Von Blotzheim and Bauer 1980). Hunting becomes very difficult, if not impossible, for the owl with a snow cover over 10–15 cm (Juillard 1984, Schönn 1986), limiting distribution in both latitude and elevation. Only one observational record exists for the Opochka district (Pskov Region, north of Leningrad, Russia) and the species is extremely rare in Estonia (Malchevskiy and Pukinskiy 1983) and probably exinct in Latvia too. Figures 5.2–5.3 illustrate the northern border of the global distribution at different spatial scales. The Republic of Bashkortostan forms the northern limit around the Ural Mountains (Karyakin and Kozlov 1999), where only a few breeding pairs have been recorded.

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(A)

Figure 5.1 Global distribution of Little Owl. (A) EBBA2 50
50 km accuracy for Continental Europe. (B) Article 12 of Birds Directive at 10
10 km accuracy for EU28.

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(B)

Figure 5.1 (cont.)

5.1 Distribution

(A) Breeding assessment Possible

(673)

Probable

(449)

Confirmed (1220) Not Available

(8)

(B) Abundance 1-9

(370)

10-99

(957)

100-999

(758)

1,000-9,999 (236) Not reported (29)

Figure 5.2 European distribution of Little Owl in 50
50 km grid cells (after Keller et al. 2020). (A) Breeding evidence. (B) Abundance.

The southern limit is northern Africa where the species is found north of the Sahara Desert in the mountainous regions of Aïr (Niger), Tibesti (northwest Chad), Am Djarass (Ennedi, northeast Chad), Murzuq (Lybia), Mellit (Sudan) and south through Sudan and Ethiopia to Somalia. Further eastward the species is found in the Arabian Peninsula, Kuwait, Iraq, Iran, Pakistan, Kashmir, the Tibetan Plateau and north Szetschwan to the Yellow Sea south of Xinhailian, China.

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Chapter 5: Distribution, Population Estimates and Trends

Figure 5.3 EU28 distribution in 10
10 km grid cells of Little Owl as obtained from data (2018) reported by EU Member States to the European Commission under Article 12 of the Birds Directive (after European Conservation Agency 2021).

5.1.2 Elevation In the northern and middle parts of its range the Little Owl is a lowland species that is rarely found above 600 m, even in mountains of central Europe (Glutz Von Blotzheim and Bauer 1980). Further south, it has been found up to 1140 m in the Causse Méjean (Lozère, France) (Juillard et al. 1992), 1200 m in the Spanish Pyrenees (Kostrzewa et al. 1986), 1230 m in the Orobie Alps (Lombardia, northern Italy) (Mastrorilli 2001), 1900–2000 m in Georgia and Armenia, up to 1260 m (Parashka town) in the Lviv Region (Kijko and Yakubenya 1995), at 1600 m in Catalonia (northeast Spain), up to 2300 m in favorable territories in Sierra Nevada (southern Spain) (Olea 1997), up to 2300 m in Bulgaria (Simeonov and Delov 1989), up to 2000 m in Armenia (Lyaister and Sosnin 1942), up to 2200–2300 m in Uzbekistan (Abdusalyamov 1971), up to 2300 m, probably even higher, in Gissar-Karategin, Tajikistan (Popov 1959), up to 2000–2800 m in Altai, up to 2800 m on the southern side of the Todra gorges, Morrocco (Thévenot et al. 2003), 4200 m in Pamir (Dementiev and Gladkov 1951) and sometimes higher in Tajikistan (Beik at 4260 m, Zor-Kul and Bash-Gumbez at 4200 m; Abdusalyamov 1971) and 4400 m in Turkey (Kasparek 1992). In central Europe the population density tends to decrease with elevation in Germany (Loske 1986).

5.2 Population Numbers The species is a widespread resident across much of Europe (except the north), which accounts for less than half of its global range. Its European breeding population is large

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5.2 Population numbers

(618 000–1 170 000 pairs, BirdLife International 2015), but has undergone a moderate decline between 1970 and 1990. Although the species was stable or increased across parts of its European range during 1990–2000, several populations have declined and the species has probably undergone a moderate decline overall in that timespan. Consequently the species has been provisionally evaluated as Declining by BirdLife International (2004). In several countries conservation activities have proven successful from 2008–2012, resulting in the status Stable in Europe (BirdLife International 2015) and Decreasing in the EU28 (European Conservation Agency 2021). Little Owl populations are fluctuating, especially in the north of the range, where marked decreases follow severe winters (Büchi 1952, Poulsen 1957, Dobinson and Richards 1964, Kämpfer-Lauenstein and Lederer 1995). Some populations recover after severe winters; however, in some countries such winters result in local extinction when habitat deterioration comes into play. In northern Europe the distribution is shrinking, i.e., Estonia and Latvia no longer have Little Owls. Denmark is suffering probably terminal declines. Recent decreases, often marked, over much of Europe have been observed. They were ascribed mainly to habitat changes, including loss of suitable nest sites (offset in some areas by provision of artificial sites – see, e.g., Juillard 1980, Ullrich 1980, Bultot et al. 2001). Estimation of population numbers are subject to possibly severe misinterpretations (Génot and Lecomte 1998). This is partly due to the fact that most researchers work in areas more densely populated by owls (K. M. Exo personal communication). The following is an overview of the three main methods by which population estimates are made.

5.2.1 Population Estimates Through Consolidation of Study Results Across a Geographic Region Consolidation of geographic results is the simple addition of locally based owl numbers. Using geographic population numbers has several drawbacks, i.e., data are never recorded in one single year, sometimes with a spread of more than 10 years, and during this period population numbers may fluctuate substantially. Further, data for these estimates are generally obtained through the use of inconsistent methods, i.e., some observers record singing males, while others record singing individuals or confirmed breeding pairs. Finally, the habitats vary from one place to another, and even within regions, making extrapolations error-prone. The main advantage of this estimate is that a minimal population is obtained without risking overestimations.

5.2.2 Population Estimates Through Partial Densities in Different Habitats These estimates are derived through main habitat associations, whereby owl numbers and habitats within known study areas are recorded, and then extrapolated to areas without owl surveys, but in which the main habitats are mapped. These estimates

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Chapter 5: Distribution, Population Estimates and Trends

assume that strong habitat preferences exist. Previous work on the Little Owl has identified a potential correlation between owl numbers and the percentage of grassland (Exo 1983, Loske 1986, Génot and Wilhelm 1993, Zuberogoitia 2002). On a larger scale, similar observations were made (Van Nieuwenhuyse et al. 2001b). However, a recent study in Belgium was not able to find any association of the species with grassland (Van Nieuwenhuyse and Bekaert 2002). In France, no correlation between average population densities and the area of grassland was found (Ferrus et al. 2002). Thus, researchers are cautioned against using grasslands as an estimator for the population of Little Owls. Using average densities of the species to calculate population numbers only makes sense when habitat-specific calculations are made. Further, this is only reasonable if an indication of the small-scale mosaic-like landscape structure is taken into account, e.g., using the length of parcel perimeters instead of areas (Van Nieuwenhuyse et al. 2001b). An additional limitation to this method is that it does not take the clustered distribution of the species into account, as seen when apparently unsuitable habitats are occupied and apparently suitable habitats remain empty (Génot and Lecomte 1998).

5.2.3 Population Estimates Through Habitat Modeling A final method to estimate population numbers is through statistical modeling using habitat characteristics of grid cells that are, in turn, based on the area used by a breeding pair (i.e., 25 ha) (Van Nieuwenhuyse et al. 2001c). After a complete survey of a region covered by 25 ha grid cells, habitat models are estimated through logistic regression analysis. These models predict the probability that, based on the habitat conditions within the grid cell, a cell will harbor Little Owls. Following this, all of the cells containing a probability of 50% or more are counted and summed for the region. A range of population numbers is obtained by estimating using different models (stratified or not). Estimates through habitat modeling require both a large number of volunteers, a consistent survey method (see Johnson et al. 2009) and reliable digital descriptions of the landscape. More and more countries are assembling national working groups that organize volunteers, and more digitized geographic datasets are becoming available. Ilanloo et al. (2020) used MaxEnt to model habitat suitability in Iran. This maximum entropy algorithm is based on a machine learning technique that evaluates the probability of the distribution of maximum entropy values affected by limitations from environmental variables that are important for the species distribution (Elith et al. 2011). Modeling based on this method only needs presence data and has the ability to consider both continuous and discrete variables in the model. In addition, the method helps to identify the most important environmental variables affecting species distribution. Ilanloo et al. (2020) used 70% of the presence data for model creation and 30% for model validation. The area under the curve (AUC) acquired from an ROC (receiver operating characteristic) curve is used to evaluate the model. Distance to forests (51.2%) and distance to human settlements (16.2%) were the most important variables in habitat selection in Iran.

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5.3 Densities

5.2.4 Population Estimates and Trends Despite the shortcomings of all these methods, it is still possible to give a rough overview of population numbers around the distribution range. It should be stressed that the data quality that we present is very heterogeneous from one country to another. For the European countries that were included in the EBCC Atlas (Van Harxen in Keller et al. 2020), the data were collected using similar methods across Europe. The historical and current population estimates are given in Table 5.2. The recent observed trend in maximum estimates in Little Owl populations was negative throughout Europe for countries that had details available in 1994 (Manez in Tucker and Heath 1994, BirdLife International 2004, Van Nieuwenhuyse et al. 2008). Recent trends are more positive, in some countries due to conservation activities. Some central European countries have undergone a well-documented negative progression between 1994 and 2004, i.e., Czech Republic –9%, Germany –24%, Poland –50%, probably due to a severe winter in 2001/2002 (G. Grzywaczewski personal communication), which continued till 2020, except for Germany. Other countries have undergone a decrease due to a reduction in reproductive offspring, i.e., the Netherlands –46% (Willems et al. 2004) or Luxembourg –43%, UK –29%, Slovenia –63%. This trend continued till 2021 in some central European countries, e.g., Czech Republic –50%, Slovenia –70%, Slovakia –40%, Austria –50%. Moreover, recently Little Owl populations have appeared to recover or become stable, e.g., Germany, short-term growth of 60–106% and Belgium, long-term growth of 16%. Switzerland featured a recent increase of 153% in its few small, well-protected and managed populations (Meisser et al. 2016). For other countries some important ajustments to the maximum population estimates were carried out compared to Manez in Tucker and Heath 1994, either upwards (Belgium +115%, Hungary +25%, Portugal +50%, Spain +54%, Denmark +33%) or downwards (France –30%, Greece –90%, Italy –40%). Population estimates report stable populations in 2004 for the UK, Germany, Portugal, Belgium, Austria, Greece and Italy. From 2004–2020 the UK showed a severe decline of –48%. In Groningen (the Netherlands), increasing fragmentation of a decimated population featured a negative population trend that more significantly affected territories that were isolated compared to those that were clustered, despite their more favorable habitat composition (van’t Hoff 2001).

5.3 Densities Using European abundancy data on the numbers of owl pairs (Figure 5.4) and the total area of each country in Europe, we calculated the density of the species for earlier and current data using the surface area of each country and the breeding area as obtained from European Conservation Agency (2021). We found a significant relationship between the latitude and the maximum observed densities (European Bird Census Council; Van Nieuwenhuyse et al. 2008) when removing Portugal from the analysis (due to extremely high densities). The density drops to 0.09 pairs per km² for each increase of 1000 km latitude (Figure 5.4).

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156

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Table 5.2 Historical and current population estimates (1994–2004 and 2015–2021) Manez (1994)

Min pairs Albania Armenia Austria Azerbaijan Belarus Belgium Bosnia and Herzegovina Bulgaria Croatia Cyprus Czech Republic Denmark France Georgia Germany Gibraltar Greece Hungary Italy Kosovo Latvia Lithuania Luxembourg

Max pairs

5000

10 000

40

60

2000 4500

4000 6600

4000 6000 2000 700 150 10 000

10 000 8000 4000 1100 150 50 000

5000

BirdLife International (2004)

Van Nieuwenhuyse et al. (2008)

BirdLife International (2015)

Min pairs

Min pairs

Min pairs

Max pairs

Max pairs

Max pairs

European Environment Agency (2021) Min pairs

4000 800 70 2000 400 12 500

8000 1500 100 10 000 1000 14 000

4000 800 60 2000 400 9000

8000 1500 60 10000 1000 14 200

4000 1000 130 2000 400 8000 2000

8000 1500 170 10 000 1000 13 000 3500

8000 1000 15 000 400 200 60 000

10 000

5000 500 5000 200 100 20 000 Present 5800

6100

4000 6000 2000 500 175 10 330 3500 7000

10 000 8000 4000 1000 200 35 000 4000 7600

10 000 4000 4000 250 43 21 000 Present 7500

5000 1500 10 000

10 000 2000 50 000

5000 1500 30 000

15 000 2500 50 000

5000 2000 10 000

1000 2500 30 000

15 000 2500 70 000 6000

10 10 80

30 50 150

10 5 40

30 10 80

10 5 45

30 10 85

5000 1500 40 000 4000 0 1 12

Max pairs

Mean (Min, Max) pairs

140

190

165

7900

12 200

10 100

14 000 6000 10 000 500

5000 4000 4000 100

8000 6000 10 000 150

50 000

25 000

50 000

6500 5000 7000 125 10 37 500

9000

7500 1 5000 3000 40000

8500 5 15 000 4000 70 000

8000 5 10 000 3500 55 000

5 20

10 30

0 8 25

10 25

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FYRO Macedonia Moldova Montenegro Netherlands Poland Portugal Romania Russia Serbia Serbia and Montenegro Slovakia Slovenia Spain Switzerland Turkey Ukraine UK Total incl. Turkey Total excl. Turkey Total excl. Turkey and Russia 157

EU28

1400

2400

1400

2400

3000

7000

3200 1000 7000 500 58 000 15 000 50 000 10 300

4200 2000 9000 1000 137 000 40 000 70 000 15 000

7500 500 40 000 15 000

8500 1000 60 000 40 000

8000 750 50 000 27 500

700 150

300 100

600 150

450 125 39 433

2338

4888

3613

167 264

299 033

272 644

5000

7000

3200

4200

3200

4200

9000 1000 10 000 20 000 10 000

12 000 3000 100 000 40 000 100 000

5500 1000 50 000 40 000 10 000

6500 2000 150 000 60 000 100 000

5500 1000 50 000 20 000 11 500

6500 1500 150 000 40 000 103 300

10 000

15 000

14 000

22 000

800 500 50 000 30 5000 11 000 6000 184 320

1000 800 65 000 40 50 000 12 000 12 000 568 980

800 150 20 000 60 300 000 15 000 5800 555 840

1000 200 100 000 70 600 000 22 000 11 600 1 267 900

800 200 36 643 91 5000 15 000 4000 235 159

1000 300 100 000 101 50 000 22 000 8500 649 986

400 100 39 433 80 300 000 15 000

110 600 000 22 000

617 849

1 128 365

179 320

518 980

255 840

667 900

230 159

599 986

317 849

528 365

169 320

418 980

245 840

567 900

218 659

496 686

267 849

458 365

Chapter 5: Distribution, Population Estimates and Trends

Cyprus

Belgium

y = –9E–08 meter latitude + 0.5859 R² = 0.1818 Albania

Netherlands

Maximum density

Yugoslavia Romania Italy Spain

Greece

Moldova, Republic Of

Croatia

France

Bulgaria

United Kingdom Luxembourg

Slovenia Turkey

Georgia Switzerland

Ukraine Austria

Germany

Latvia Belarus Poland Russian Federation Lithuania

Latitude

Figure 5.4 Relation of latitude and population densities (densities calculated as population estimates divided by the area per country (data after Manez in Tucker and Heath 1994).

The local density of a wildlife population can have a strong “feedback” effect on the demographic performance of that population. For example, the higher the local density, the fiercer the competition (for food and territory) might be and the greater the subsequent impact on breeding success will be (Newton 1998). With this in mind, we focus this section on examining Little Owl densities that have been observed within the breeding range of the species. Densities of owls are best determined through the use of radio-telemetry, with detailed locations over a full year (or more) on both male and female owls, yielding an accurate determination of the area (ha) being utilized by a pair of owls. More frequently though, densities are measured as the number of observations (e.g., pairs, calling males, calling individuals) per km². Also, densities are given by quantifiying the distances between neighboring owls (called the “nearest-neighbor distance”). Amongst the publications we reviewed for this book, numbers of Little Owls have been reported in several different ways, making comparisons difficult. Some authors report owl numbers obtained by playback; however, these are often (incorrectly)

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interpreted and reported as confirmed breeding pairs. In some other cases calling males are reported, and in others all calling individuals are reported, no matter the sex. Some authors denote the density of owls as the number of territories, or the number of breeding pairs, for a given study-area size. While this type of density estimate often reflects the number of territorial pairs within the studied area, it may not reflect the actual area used by the pairs within it (e.g., owls used habitat outside of the study area, or, conversely, there may have been substantial areas within the study area that were not used by owls). In particular, while small study areas (e.g., about 50%) of the breeding range of the species, even Hessen (with a population increase asssumed) shows a loss of about one-third of the breeding range occupied in the 1970s. Even in NorthrheinWestphalia, some parts of the former breeding range were lost, e.g., the higher parts in south Westphalia and parts of the industrial area Ruhrgebiet. 5.5.7.3 DENSITIES In Germany densities recorded below 1 territory/km² were reported from Saxony, with 12 pairs on 20 km² (Augst and Manka 1997). While higher densities were once found in

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Northrrhine-Westphalia (Exo in Galbraith et al. 1992) the situation has changed in the Aachen region where only 34 calling males were recorded on 160 km² (Toschki 1999). In Bönningheim, Landkreis Ludwigsburg, densities up to 1 pair/km² were recorded locally (Eick 2003), with an average of 0.17 pairs/km² for the entire region (120 pairs across 690 km² (Keil 2001). In the orchards of southwest Germany, a density of 3.5 breeding pairs/km² was found, with a nestbox density of 1 box per 15 ha (Otto and Ullrich 2000). The population center in northwest Germany, which is dominated by the Atlantic lowland ranges from the Niederrheinischen Tiefland and the Kölner Buch far into Münsterland, can reach densities of 21–50 or 51–150 territories per grid cell (Gedeon et al. 2014). This occurrence currently comprises around 70% of all breeding pairs in Germany and, with adjacent stocks in the Netherlands and Belgium, forms one of the most important density centers in Central Europe. The populations in the Oldenburger Münsterland have up to 21–50 territories per grid cell, largely uninterrupted towards the East Frisian Oldenburg Geest. More isolated occurrences can also be found within the Ems and Wesermarschen, as well as along the Aller and Leine. The concentration within the low mountain range extends from the Oberrheinischen Tiefland to Westhessische Bergland and the central Neckar area. With 51–150 territories per grid cell there are density centers in the Wetterau, in the Rhine-Main area and in the Neckar valley near Stuttgart. Separate from this are smaller clusters in the area of the Bliesgau, the Saargau, north of the Moselle and in the Grabfeld, east of the Rhön. Isolated occurrences with 1–3 territories per grid cell are found in the Weserbergland and the Fulda valley on the Vogelsberg, as well as areas along the Tauber, in Steigerwald and in the Zittauer Becken. The only occurrence in the Alpine foothills is located in the Bodenseebecken near Markdorf. A smaller concentration is found on the Schleswig-Holstein Geest, in particular in the Hohe Geest and in the river plains of Eider and Stör, where densities of 8–20 territories per grid cell were reported (Gedeon et al. 2014).

5.5.8 Denmark 5.5.8.1 TRENDS An extreme restriction in the distribution of the Little Owl has taken place during the last four decades and the species was only found in 2% of the atlas squares of Atlas III 2014–2017, half of them confirmed as breeding. The total number of breeding records has been reduced by 79% between the Atlas surveys in 1993–1996 and 2014–2017 (Vikstrøm and Moshøj 2020) (Figure 5.20). 5.5.8.2 DISTRIBUTION The major part of the Danish Little Owl population breeds in north and west Jutland. The most import areas are Himmerland (between Ålborg and Mariager), Salling (north of Skive) and the central part of Ringkøbing County. Outside these areas, small populations are found in Vendsyssel (north of Ålborg, between Kattegat and Fjerritslev, north to Hjørring), in the region between Randers Fjord and Mariager Fjord, on Djursland

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Breeding Distribution Confirmed/Probable Possible

1971–1973

(b)

Breeding Distribution Confirmed/Probable Possible

1993–1996

Figure 5.20 Historical distribution of the Little Owl in Denmark in (a) 1971–1973, (b) 1993–1996, (c) 2003 and (d) 2014–2017 (after DOF, BirdLife Denmark and the Museum of Zoology, Copenhagen). Large dots represent confirmed breeding, small dots possible breeding. Reproduced with permission from Dansk Ornitologisk Forening/ BirdLife Denmark (DOF BirdLife).

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(c)

Breeding Distribution Confirmed/Probable Possible

2003

(d)

Breeding distribution Confirmed Probable Possible

2014–2017

Figure 5.20 (cont.)

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(between Randers/Århus and Grenå) and in the western part of Ribe County. In the counties of Sønderjylland and Vejle only a few scattered breeding records exist. In Fyn only one confirmed breeding record and another possible one has been recorded. The Little Owl was found breeding in Falster in 1937 but has probably not bred on the islands east of Store Bælt (Great Belt) since the 1940s (Grell et al. 1998). In 2021 the major part of the remaining Danish Little Owl population was breeding in northern Jutland. The most important area was Himmerland (between Aalborg and Hobro). Outside this area only a few scattered breeding records exist annually (Vendsyssel north to Aalborg and in the central and southwestern part of Jutland close to Esbjerg (Vikstrøm and Moshøj 2020, Sunde 2021). 5.5.8.3 POPULATION ESTIMATES Fewer grazed pastures close to appropriate buildings for nesting, together with the general decrease in biological diversity caused by agricultural intensification, possibly pesticides and over-fertilizing in open country, have been proposed as some of the main causes of decline (Grell et al. 1998). The species also seems to be quite vulnerable to the increasing levels of faster motorized traffic over the years (Glue 1971a). Lack of good nesting sites due to better maintenance of buildings and predation by Stone Martens (Martes foina) are also possible problems. BirdLife International (2004) estimated the total population at 100–200 pairs. BirdLife International (2015) estimated the total population at 43 pairs in 2008–2012. In 2013–2018, the population was estimated at 10 breeding pairs (European Environment Agency 2021). In 2019 and 2020 only 9–11 pairs were known with an additional seven or eight single birds, so the Little Owl is very close to extinction in Denmark (Sunde 2021). This is a very critical situation and most of the pairs are fed by food supplementation with small dead chicks, some only in the breeding season and others all year around (Sunde et al. 2021). 5.5.8.4 TRENDS An extreme reduction in the distribution of the Little Owl has taken place during the last two decades of the twentieth century. The total number of breeding records has been reduced by 65% during 1993–1996, compared with the results of the first atlas project in 1971–1974. Approximately 300 atlas squares distributed throughout the area of Jutland and Funen that reported breeding in 1971–1974 did not report any breeding activity during 1993–1996. In particular, a high proportion of the deserted breeding areas were observed in eastern and southern Jutland and Funen. But the species has also apparently disappeared from Thy (north of Limfjorden and west of Fjerritslev) and on Mors, in western Vendsyssel, and in middle and western Jutland (Grell et al. 1998). Further reduction in distribution has taken place over the last four decades and Little Owls were only found in 2% of the atlas squares in Atlas III 2014–2017, half of them confirmed as breeding. The total number of breeding records has been reduced by 79% between the Atlas surveys in 1993–1996 and 2014–2017 (Vikstrøm and Moshøj 2020).

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5.5.9 France 5.5.9.1 DISTRIBUTION In France, the Little Owl is a sedentary species, present across the whole country except the mountains. Yeatman (1976) indicated that the mountains where the snow stays for a long time are not suitable for the species. The species breeds up to 1080–1100 m on the Causse Méjean in Lozère and up to 1155 m in Haute-Loire (Juillard et al. 1990). The Little Owl is absent from the islands of Brittany (Guermeur and Monnat 1980), but is very common on the island of Oléron (Bavoux and Burneleau 1983, Bretagnolle et al. 2001). The species is very rare in Corsica, where just a few cases of breeding have been recorded in the last century, in the middle-east plain, near Alerià (Thibault 1983, Thibault and Bonaccorsi 1999). The last breeding record for Corsica was in 2000 (Mastrorilli 2000). The species is believed to compete with the Scops Owl (Otus scops) on Corsica, and is present on the island of Frioul, not far from Marseille (Cheylan 1986). Population strongholds are found in the west between Normandy, Pays-de-la-Loire and Midi-Pyrénées, northeast of Massif Central (Auvergne and Rhône-Alpes) and along the Mediterranean Sea between Provence and Pyrénées-Orientales. Elsewhere densities decline, especially in the northeast between Portarlier and Etretat (Figure 5.21) (Hameau in Issa and Muller 2015). Most of the adults remain in their territories in autumn and winter. Juveniles disperse from September to October, principally within a radius of 10 km around their place of birth. The distribution in France reflects the specific situation where Mediterranean populations are inter-connected to populations

Breeding evidence

Confirmed (1197) Probable

(1039)

Possible

(716)

Figure 5.21 Little Owl distribution in France 2005–2012 (after Issa and Muller 2015).

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in the neighboring countries of Spain, Italy and Belgium. For most of France, the Little Owl is distributed in population clusters, sometimes irrespective of the apparent quality of the habitat (Génot and Lecomte 1998). 5.5.9.2 POPULATION ESTIMATES The French population of the Little Owl was estimated at 5000–50 000 pairs at the beginning of the 1990s (Génot 1994b) and 11 000–35 000 pairs in 1998 (Génot and Lecomte 1998). A detailed analysis was done by Génot and Lecomte (1998) yielding population estimates per administrative district (Table S5.4). The total minimal population at the end of the 1990s was estimated at 10 330–35 000 pairs by summing partial estimates (Génot and Lecomte 1998). BirdLife International (2004) estimated the total population at 20 000–60 000 pairs. Issa and Muller (2015) estimated the population at 25 000–50 000 pairs in 2009–2012, BirdLife International (2015) estimated the total population at 21 000–50 000 pairs in 2008–2012. In 2013–2018, the population was estimated at 25 000–50 000 breeding pairs (European Environment Agency 2021). 5.5.9.3 DENSITIES In 1997, Camuzat and Faucon (unpublished data) found 70 calling males in an area of 44 km² (1.6 males/km²). In 1998, Vivier and Telle (unpublished data) recorded 115 calling males in an area of 95 km² (1.2 males/km²) in meadows with pollard willows in northern France. In 1993, Geslin (unpublished data) recorded 24 calling males in an area of 12 km² (2 males/km²) in the Loire valley and Gailliez (unpublished data) noted 136 calling males/133 km² (1.02 males/km²) in orchards and hedges of northern France. One territory/km² was found in Bouches-du-Rhône (Barthelemy and Bertrand 1997). In 1999–2000, 157 calling males/320 km² were recorded in western France, with the highest average density in the edge of the “bocage” (0.62/km²) and the lowest average density in the sandy dunes area (0.05/km²) (Signoret 2002). Crespon and Chretienne (unpublished data) recorded 88 calling males/1175 km² in the natural regional park of Perche, with average densties of 0.07–0.83/km². Locally high densities of 6.7 calling males/km² were found on Île d’Oléron (18 km²) (Bretagnolle et al. 2001). Monitoring in 10 regional parks revealed densities ranging from 57 calling males/44 km² in LivradoisForez (1.3 males/km²) to 7 calling males/200 km² in Lorraine (0.035 males/km²) (Génot in Van Nieuwenhuyse et al. 2008). 5.5.9.4 TRENDS Issa and Muller (2015) reported an evolution in distribution patterns between 1985–1989 and 2005–2012 of 524 versus 1197 confirmed, 272 versus 1039 probable and 90 versus 716 possible occupied grid cells. A limited decline was reported in 1975–2012 and a stable situation in 2000–2012. In 1999 an overview of regional atlases showed a population decline of 20–50% since 1970 (Rocamora and Yeatman-Berthelot, 1999). Between 1970 and 1985, 22% of grid cells in Bretagne were abandoned (Clec’h 1993). In Isle-de-France, 1000 pairs were estimated in 1950 dropping to 300-400 pairs in

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1990 (Lecomte, 1995). The population of Vaucluse dropped from 700 in 1983 to 350 in 1993 (Olioso 1996). In the Vosges du Nord, 19 pairs in 1984 dropped to 9 in 1991 and recovered to 19 in 1996 (Génot 1992c). Since the monitoring project Observatoire National Inter-Parcs unfortunately stopped in 2008, a representative view on national trends is no longer available (Hameau in Issa and Muller 2015).

5.5.10 Spain 5.5.10.1 DISTRIBUTION The Little Owl nests almost everywhere in the Iberian Peninsula, but is absent from the Balearic and Canary archipelagos, where it has only been recorded in winter in Palma de Mallorca (Olea 1997), suggesting migration of the species to that regioin. The species avoids excessively wet zones, dense forests and high mountain habitats (Muntaner et al. 1983, Olea 1997). The Little Owl is less common in the Euro-Siberian Region than in the Mediterranean Region of the Iberian Peninsula. This could be indirectly related to the weather, e.g., the oceanic weather favors forests that are avoided by the species (Zuberogoitia and Martínez-Climent 2001). However, there are high-density populations of Little Owls in places with traditional agriculture and poultry breeding, and their associated field and grasslands. They are not common in mountainous areas, although there are populations established in more open areas at higher elevations in the Pyrenees (1600 m) and Sierra Nevada (2300 m). Muntaner et al. (1983) and Urios et al. (1991) observed that the winter temperature was also a limiting factor. In fact, Muntaner et al. (1983) established the distributional limit as the 1C isotherm for January in Cataluña and Andorra, and Urios et al. (1991) identified the 3C isotherm as the distributional limit in Valencia. This can be correlated with other variables, like the persistence of snow cover during winter that makes it difficult for the owls to find adequate prey. 5.5.10.2 POPULATION ESTIMATES According to Purroy (1997) there were 50 000–65 000 estimated breeding pairs in Spain for the period 1975–1995. The Atlas de las Aves reproductoras de España (Marti and Del Moral 2003), suggests the Spanish Little Owl population to be at least 36 000 pairs, although it is necessary to point out there is no abundance data for almost 25% of the squares (each square being 625 km²) where the species was recorded (Garcia and Muñoz 2003). The map of the III Atlas de las Aves en Época de Reproducción en España (Figure 5.22) (Molina et al. 2021) only reports confirmed breeding in 1988 grid cells for 2020 compared to 1675 grid cells in 1998–2002 (Marti and Del Moral 2003). This might indicate an increase, but is probably due to less detailed data gathering in the most recent survey. A long-term reduction of more than 20% of the population has been observed over the last 30 years, following the European trend. However, the short-term population tendency for the species was considered to be positive during 1998–2001. Furthermore, the Little Owl is reported as the most abundant nocturnal raptor in Spain (SEO/BirdLife 2002). Changes in agricultural practices and land use are the main factors responsible

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Figure 5.22 Little Owl distribution (a) and probability of occurrence (b) in 2020 in Spain (after Molina et al. 2021).

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for the decrease of the species. Urban development plans are a real threat, especially in the eastern coastal semi-arid habitats and in the Basque countryside on the Atlantic coast (northern Spain) (Zuberogoitia 2002, Martínez and Zuberogoitia 2004a). The reduction of dry-farmed tree crops, in particular the carob tree (Ceratonia siliqua), has caused severe declines on the eastern coast. Pesticides diminish prey availability, land re-allocation schemes reduce suitable sites for nesting and hunting, and the reduction of hedges and trees along roads increases the risk of collisions with vehicles (Olea 1997, Garcia and Munoz 2003). Likewise, the enlargement of forested areas, especially in the Pre-Pyrenees has led to a reduction in suitable habitats (Martinez and Zuberogoitia 2003, J. Estrada personal communication). BirdLife International (2004) estimated the total population at 20 000–100 000 pairs. BirdLife International (2015) estimated the total population at 39 433 pairs in 1998–2002. In 2013–2018, the population was estimated at 39 433 breeding pairs (European Environment Agency 2021). 5.5.10.3 DENSITIES There is limited data on Little Owl abundance in the Iberian Peninsula: 0.2 individuals/ km² in Granada (southern Spain), up to 1 pair/km² in Catalonia, and 0.03–0.11 pairs/ km² in Galicia (northwest Spain) (Olea 1997). Fajardo et al. (1998) recorded Little Owl numbers during road surveys in the province of Seville (southern Spain). During the breeding season, they recorded 17 individual owls/km² in olive groves and seven individuals/km² in sunflower fields, respectively. During July, they recorded up to 86.8 individuals/km². Zuberogoitia and Campos (1997) found 1.3 territories/km² in Biscay; Olea (1997) reported 1 pair/km² in olive plantations and Pinus halepensis forests in Cataluna.

5.5.11 Portugal 5.5.11.1 DISTRIBUTION The Little Owl is probably the most common and widespread owl in Portugal. Iberian breeding populations are sedentary, and young birds undertake local movement. There is evidence that some peninsular birds could be wintering in Iberia (Díaz et al. 1996). The species is more common south of the River Tagus, mainly in the provinces of Alto Alentejo and Baixo Alentejo (Rufino 1989), in southern Portugal. It is scarce or absent in the extensive forest areas of central and northern Portugal and occurs in a great variety of habitat types including regions from sea level to over 1000 m. Little Owls are frequently found in parks and gardens in cities, small towns and villages. It is a common species in Lisbon, frequenting the great urban parks and some gardens. Although uncommon, they can be found using the upper parts of buildings (Reino in Van Nieuwenhuyse et al. 2008). Figure 5.23 shows the detailed distribution in 2005–2014 (Lourenço et al. 2015) compared to 1999–2005 (Equipa Atlas 2008). 5.5.11.2 POPULATION ESTIMATES As of 1989, the estimate for the Portuguese Little Owl population was between 10 000 and 100 000 pairs with populations considered stable (Manez in Tucker and

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Figure 5.23 Detailed distribution of the Little Owl (Athene noctua) in 2005–2014 (large circles) versus 1999–2005 (small circles Equipa Atlas 2008) (after Lourenço et al., 2015).

Heath 1994). The latest estimate for the Little Owl population in Portugal was 50 000– 150 000 breeding pairs, and probably closer to 90 000 pairs (Tomé in Van Nieuwenhuyse et al. 2008). BirdLife International (2004) estimated the total population at 50 000–150 000 pairs. BirdLife International (2015) estimated the total population at 58 000–137 000 pairs in 2008–2012. In 2013–2018, the population was estimated at 40 000–60 000 breeding pairs (European Environment Agency 2021). 5.5.11.3 DENSITIES In southern Portugal (Bixo Alentejo) densities of up to 2.36 pairs/km² were recorded in 16 km² of steppe-like habitat, and 6.95 pairs/km² in an area of 6 km² of open Holm-oak Quercus rotundifolia (Tomé in Van Nieuwenhuyse et al. 2008). During 2010–2017 the Working Group on Nocturnal Birds of SPEA (GTAN-SPEA) carried out a volunteer monitoring program (NOCTUA-Portugal) to determine the population trends of seven owl species at a national scale (Lourenço et al. 2021). They used generalized estimating equation models to assess trends. In addition, they used the distribution data from breeding bird atlases, observations sent by collaborators and data from the public online database PortugalAves/eBird to detect changes in distribution over a four-decade period (1978–2017). Four periods were defined to study potential changes in distribution of owls in Portugal: 1978–1984 (first breeding bird atlas), 1999–2005 (second breeding bird atlas), 2006–2014 (interval between second and third breeding bird atlases) and 2015–2017 (ongoing third breeding bird atlas). The Little Owl had negative population and distribution trends. Figure 5.24 shows the evolution in the four sampling periods since 1978.

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Figure 5.24 Distribution of the Little Owl (Athene noctua) in the sampling periods: first breeding bird atlas BBA1 (1978–1984), second breeding bird atlas BBA2 (1999–2005), period between second and third breeding bird atlases – inter-atlas (2006–2014), third breeding bird atlas BBA3 (2015–2017) (after Lourenço et al. 2021).

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3.5 3.0 2.5 2.0 1.5 1.0

Breeding pairs/10 x 10 km square

4.0

5.5 Overview per Country

2010 2011 2012 2013 2014 2015 2016 2017 Year Figure 5.25 Annual abundance estimates (number of breeding pairs per sampled 10
10 km square with 95% confidence intervals) for the Little Owl (Athene noctua) in the period 2010–2020 resulting from the NOCTUA-Portugal monitoring program (after GTAN-SPEA 2021).

5.5.11.4 TRENDS Figure 5.25 shows the evolution of the abundance estimates per 10
10 km square (GTAN-SPEA 2021). The distribution trend estimates for 1978–2017 (Lourenço et al. 2021) gives a percentage of the sampling units with breeding/presence information for four periods, i.e., 1978–1984, BBA1 first breeding atlas, 92% occupation; 1999–2005, BBA2 second breeding atlas, 74% occupation; 2006–2014, inter-atlas period between second and third breeding atlas, 64% occupation; 2015–2017 BBA3 third breeding atlas, 65% occupation. The eight-year population trend for 2010–2017 from a GEE-GLM model yields an estimated index decline of –0.24.

5.5.12 Italy 5.5.12.1 DISTRIBUTION In Italy the Little Owl is a sedentary species, being widespread across the mainland, but can also be found on the isles of Sardinia, Sicily and others (Casini in Meschini and Frugis 1993) (Figure 5.26). Dispersal and movement of owls occurs in autumn and winter, and some autumn movements can be considered as migration (M. Mastrorilli personal communication). Younger individuals are more mobile and could move for tens of kilometers (Spina and Volponi 2008). The species breeds mainly in lowlands and lower hills; more than 80% of presence locations are found below 300 m a.s.l. and more than 50% below 100 m a.s.l. The Little Owl becomes less frequent with the increase of elevation. It rarely breeds above 1000 m a.s.l., with the higher records between 1300 and 1450 m a.s.l in both the Alps and Apennines (G. Calvi personal communication). It is a well-distributed bird of prey in lowland areas and hillsides, with rare breeding records in the lower mountains. This

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Breeding evidence Confirmed (434) Probable

(370)

Possible

(881)

Figure 5.26 Little Owl distribution in Italy 2010–2016 (www.ornitho.it/archive).

explains the gaps in the distribution along the Alpine arc. Nevertheless, some breeding pairs have been recorded at higher elevations in recent years: 1000 m in Liguria (Andreotti 1989), at 1100 m in Piedmont (Mostini in Mingozzi et al. 1988), and the highest in western Europe has been recorded in the Orobic Alps, Lombardia at 1230 m (Mastrorilli 2001). Other important factors driving the species distributions are climate and vegetation: the Little Owl prefers a warm climate and avoids wide and continuous woodlands. In Italy the Little Owl is widely spread in the Po Plain and in other lowlands; it is also quite common in low hills, both on Tyrrhenian and Adriatic Apennine ridges. It also breeds on the main islands, Sardinia and Sicily, but avoiding higher reliefs. For the same reason, the species is absent from the Alpine arc and from the higher Apennine reliefs, with the exception of the main valleys (e.g., Valtellina, Aosta valley). The Italian distribution of the Little Owl in 2010–2016 (www.ornitho.it/archive) follows that of the early 1980s (Casini in Meschini and Frugis 1993) with the main exception of the northern Apennines and other low reliefs where forest expansion is the most likely driver of local extinction. Between 1988 and 2004 the Little Owl was recognized as the most common bird of prey in Italian towns due to the high number of urban parks and wooded boulevards (with owls showing a preference for species such as Poplar Populus sp., Plane Platanus sp. and Horse-chestnut Aesculus hippocastanum), and also the urbanization of country buildings and the favorable characteristics of historical city centers (old buildings with

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plenty of hollows). Roof spaces in recently built industrial buildings are often used as breeding sites (Mastrorilli 1999). During several urban surveys, the presence of Little Owls has been observed in 52 major Italian towns. The Little Owl breeds mainly in various types of rural areas, preferring sites with traditional farming where it can rely on a wider prey spectrum and on greater availability of nesting sites, represented by farmhouses, ruins and tree holes (e.g., pollarded willows, poplars, mulberries). Small villages, especially if close to farmlands, are also often occupied. Over the past few years the Little Owl has bred more frequently in industrial facilities. In southern Italy and on the main islands lacking buildings and trees, the Little Owl nests in piles of stones. The main limiting factors for the species in Italy are loss of biodiversity in farmlands with intensive farming, cutting down of old trees with holes, demolition or renovation of rural buildings, and roadkills (G. Calvi personal communication). Due to the different weather conditions along the Peninsula, there are several areas that can be colonized by the species. On the Po Plain the species distribution is strongly affected by severe winters (i.e., snow and relatively low temperatures) causing significant population decreases. In central and southern Italy the environment and weather conditions are typically Mediterranean and thus more suitable to the owl’s ecology and for this reason populations are more stable there. The most favorable conditions for Little Owls (suitable weather, food availability, suitable habitat) are encountered in southern Italy (M. Mastrorilli personal communication). 5.5.12.2 POPULATION ESTIMATES A strong decrease was observed during 1960–1980, followed by a rapid recovery (Brichetti 1997), yielding stable populations recently estimated at 10 000–50 000 pairs (Manez in Tucker and Heath 1994) and 10 000–30 000 pairs in 1996 (Brichetti 1997). BirdLife International (2004, 2015) estimated the total population at 30 000– 50 000 pairs around 2000 and 40 000–70 000 pairs in 2006. The Italian breeding population was estimated at 40 000–70 000 territories by Brichetti and Fracasso (2006) on the basis of researchers’ experience. The European Environment Agency (2021) reported 40 000–70 000 breeding pairs in 2007–2018. There is a lack of wide-scale monitoring programs and, as a consequence, a lack of monitoring data for reliable and more precise population estimates (www.ornitho.it/archive). 5.5.12.3 DENSITIES The following densities have been reported in various areas of Italy: in mixed farmland (Ticino Park, Pavia, northern Italy) 1.1 territories/km² (Cesaris 1988); rice fields (Pavia) 0.4 territories/km² (Galeotti and Pirovano unpublished data); urban areas (Pavia) 1.25 territories/km² (Galeotti and Morimando 1991). Intensive farmland on the Po Plain, Lombardy, northern Italy) produced 1 territory/km² (Galeotti and Sacchi 1996) and the Low Alps (Lombardy) >0.5 territories/km² (Galeotti and Sacchi 1996). Table S5.5 shows density data for the owl in some Italian towns. Table S5.6 reflects densities of Little Owls in an array of Italian countryside locations. Densities are highly variable,

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depending on habitat types and can reach 8 territories/km² (Brichetti and Fracasso 2020), usually ranging from 0.5 to 1.5 pairs/km². 5.5.12.4 TRENDS The only available trend for this species refers to the period 2000–2011 and shows a moderate decline for the species (mean annual variation = –3.6%; Campedelli et al. 2012). It is worth noting that this trend derives from the national common breeding bird monitoring program, which is not aimed at monitoring owls. Some recent local atlases seem to confirm the negative trend, especially in northern Italy: in South Tyrol the species, rare during the period 1987–1991, has disappeared and has not been detected in 2010–2015 (Unterholzner et al. 2018). In Venice Province a decrease in occupied units between 1996–1998 and 2008–2012 has been recorded, during both breeding (–16%) and wintering (–42%; Bon et al. 2014). This pattern is far from being universal: in Umbria region the species has widened its distribution increasing from 49% occupied units in the period 1988–1993 to 85.3% between 2012 and 2017 (Velatta et al. 2019). In the Lazio Region and the Treviso Province the species seems stable (Mezzavilla and Bettiol 2007, Brunelli et al. 2011). The species is considered to be Least Concern in the national Red List (Peronace et al. 2012) and its conservation status is judged as favorable (Gustin et al. 2016).

5.5.13 Switzerland 5.5.13.1 DISTRIBUTION The species is present in very low numbers in four small regions : (1) in the Canton de Genève (Geneva), (2) in Ajoie, north of the Jura canton, (3) in Ticino and (4) in the Seeland region (Fribourg canton). The three main ones are in border areas with France (1), France and Germany (2) and Italy (3). A conservation initiative in the Basel region is trying to restore a link with the neighboring German and French populations through improvement and restoration of habitat, without a positive result so far for the Swiss side, but the surrounding populations are increasing (C. Meisser personal communication). The evolution of the distribution of the species is illustrated in four maps with the respective distributions of 1950–1959, 1972–1976, 1993–1996 and 2013–2016 (Figure 5.27). 5.5.13.2 POPULATION ESTIMATES The species has undergone a marked decrease, due especially to habitat changes. The Swiss population was estimated at 185 pairs in 1980 (Juillard 1980), 30–40 pairs in 1986–1991 (Manez in Tucker and Heath 1994), 70 pairs in 1992–1996 (Meisser and Juillard 1998) and 58 in 2002 (Meisser et al. 2016). But the trend has been slowly recovering since then: 90–120 in 2011–2014 (Meisser et al. 2016), 115–150 in 2013–2016 (Knaus et al. 2018) and 153 in 2021 (compilation made by BirdLife Switzerland).

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Figure 5.27 Little Owl distribution in Switzerland in 1950–1959, 1972–1976, 1993–1996 and 2013–2016 after Knaus et al. 2018. Reproduced with permission from Vogelwarte, Sempach, Switzerland. www.vogelwarte.ch.

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Around Geneva, 77 territories were counted in 2021, compared to 32 in the worst year, 20 years ago (Meisser 2022). The increase is largely due to strong growth in one area, covering half of the suitable habitats of the canton de Genève. In Ajoie, the trend is similar: from 13 territories in 2003 to 47 in 2021 (Collectif Chevêche Ajoie, N. Apolloni personal communication). Tessin has 23 pairs in 2021, which is six times more than in 2005 (Ficedula, R. Lardelli personal communication). The fragile return of the species to the Seeland region began in 2005. The number of territories has recently increased, reaching six by 2021 (Swiss Ornithological Institute Sempach personal communication). The recent increases in the three main (and still very small) populations are moderate and have not significantly changed the distribution of the species in Switzerland compared to 30 years ago, with the exception of the incipient re-colonization in the Seeland region. This is probably because potential for new populations in Switzerland remains scarce, given the low level of current suitable habitats elsewhere in the country. 5.5.13.3 DENSITIES Around Geneva, the mean density is 1.2 calling males/km² (about 60 km² of suitable habitats). The highest densities are 2.5 territories/km² (for example 24 territories over 9.5 km² in 2021; Meisser 2022).

5.5.14 Austria Since the drastic decline in the population of the Little Owl in Austria, the species has evolved from a very common species up to the 1970s to Critically Threatened and RedListed (Dvorak et al. 2017). Recently there have been intensive efforts to preserve this species. Targeted protective measures were preceded by systematic population and reproduction controls, as well as analyses of the habitat, which also accompany all measures for the purpose of evaluation. 5.5.14.1 DISTRIBUTION In Austria there are currently three more or less interacting Little Owl subpopulations (Figure 5.28). The westernmost subpopulation mainly breeds in the Machland, around Ried/Riedmark, in the Eferdinger Becken as well as the lower Mühlviertel in the federal state of Upper Austria, with a population size of 35–65 breeding pairs between 2013 and 2020 (F. Kloibhofe personal communication). The main areas of distribution in Lower Austria are the districts of Krems, St. Pölten, Tulln, Wiener Becken, Wagram, eastern Mostviertel and northwest Weinviertel, ranging between 20 and 76 breeding pairs (59 to 119 occupied territories) in the period 2013–2020 (F. Grinschgl, W. Hovorka and R. Ille personal communication). The third subpopulation breeds in the easternmost federal state of Austria, in the Burgenland. While Little Owls were found both west and east of Lake Neusiedl up to 2000, the settlement is currently limited to the east side, with a few exceptions. From 2013 to 2020 between 15 and

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Figure 5.28 Little Owl distribution in Austria (Österreichischer Bericht gemäß Artikel 12 der Vogelschutzrichtlinie, 2009/147/EG Berichtszeitraum 2013 bis 2018. Ergebnisbericht Wien, Oktober 2019. Bearbeiter: Michael Dvorak, BirdLife Österreich) (after European Conservation Agency 2021).

18 breeding pairs were reported (15 to 23 occupied territories; F. Grinschgl and R. Ille personal communication). 5.5.14.2 POPULATION ESTIMATES The species is decreasing (Glutz Von Blotzheim and Bauer 1980) and 40–60 pairs were counted in the 1990s (Manez in Tucker and Heath 1994) and 60 pairs in 1997 (Ille and Grinschgl 2001). Based on systematic searches, the population size between 1996 and 2001 was estimated at about 50 pairs and 20 single individuals (nearly exclusively males) (R. Ille personal communication). BirdLife International (2004) estimated the total population at 70–100 pairs. BirdLife International (2004, 2015) estimated the total population at 70–100 pairs around 2000 and 130–170 pairs in 2001–2012. The European Environment Agency (2021) reported 140–190 breeding pairs in 2007–2018. The minimum population size is estimated at 70–159 breeding pairs during the period 2013–2020, and the number of breeding pairs increased during this period (R. Ille and F. Grinschgl, personal communication). Higher numbers are suspected because male responsiveness to playback can be very low and pairs may be very hidden during the breeding season, especially in sparsely populated areas or if predators like Tawny Owls, Long-Eared Owls or Eagle Owls settle nearby (F. Grinschgl and R. Ille personal communication). Solitary owls in general are males (Ille and Grinschgl 2014, 2017). In recent years, local initiatives in each of the four federal provinces led to a reversal of the trend. Today the compiled estimates of breeding pairs have increased to just below 300 breeding pairs (Table 5.6) (R. Zink personal communication) making the short-term overall population trend positive.

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Table 5.6 Overview of population estimates for the Austrian Little Owl population in Austria between 2019 and 2021, monitoring efforts in Lower Austria have been highest in 2020 2019

Burgenland (Wurm and Paar 2021) Lower Austria (Pegler, Stefan and Geringer unpubl. data/Grinschgl 2020/Steiner et al. 2020) Upper Austria (Lugmair and Kloibhofer 2021) Vorarlberg (EngelKlien, Eulenhilfe Vorarlberg e. V. pers. comm.) Total (compilation)

2020

2021

Known breeding pairs

Checked breeding pairs

Successful broods

Known breeding pairs

Checked breeding pairs

Successful broods

Known breeding pairs

Checked breeding pairs

Successful broods

40

24

24

69

40

32

93

63

59

>64

approx. 100

67

93

69

67

approx. 100

67

103

56

54

83

71

7

191

Compilation by R. Zink personal communication.

78

255

163

293

126

5.5 Overview per Country

5.5.14.3 TRENDS Despite short-term fluctuations, the numbers indicate an upward trend for the Little Owl in Austria, despite the fact that the factors responsible locally for the rapid decline have turned out to be more negative in the meantime. These factors are still intensification of agriculture, decline in the keeping of farm animals, expansion of settlement areas and traffic routes, as well as loss of small-scale structured habitats that lead to a lack of suitable food-rich hunting grounds and safe breeding sites. The decline in insect populations (especially of profitable large insects) has led to an even greater dependence on the Common Vole, associated with greater fluctuations in reproductive success (R. Ille and F. Grinschgl personal communication). One reason for the population recovery in Austria is the increasing acceptance of (Stone Marten) safe nesting boxes placed in trees or on buildings, which on the one hand compensates for the lack of suitable natural breeding sites and on the other hand leads to lower breeding losses. The acceptance of nesting boxes is also increasing as the young owls that have grown up in nesting boxes accept or even prefer it for their own broods (Ille R. personal communication). In northwest Weinviertel, in the year 2009, nestboxes were only used for 22% of broods, 91.7% in 2014 and 75% in 2020. In 2020, in the Wagram area, all broods were raised in nestboxes. The use of nestboxes in Burgenland developed similarly from 20% in 2008 to 100% in 2017. Of course, this also has the disadvantage that the population can only be preserved and consistently stabilized with constant maintenance of the nesting boxes. Furthermore, protective measures by offering nestboxes may only work up to a certain population density. However, in the area around Krems, nearly all pairs successfully bred in loess caves, showing that natural breeding sites can also be safe. Another factor that could have a positive influence on population development is global warming and the decreasing amount of precipitation, which corresponds to the climatic conditions in Little Owl primary habitats associated with lower winter losses (see Chapter 10, Population Regulation). 5.5.14.4 DENSITIES Densities vary greatly, depending on habitat type, availability of food and nest sites. In Austria, Little Owl habitats are orchards (e.g., Mostviertel, Machland, Ried/Riedmark), vineyards with cellar lanes and old press-houses (e.g., northwest Weinviertel), outskirts of villages with old barns and other old farm buildings (Wagram district in Lower Austria, Burgenland), isolated courtyards (Burgenland, Lower Austria) and loess walls (e.g., district of Krems, Wagram). For Upper Austria Kloibhofer and Lugmair (2018) reported population densities between 0.4 breeding pairs/km2 (Eferdinger Becken) and 2.6 breeding pairs/km2 (Machland, Ried/Riedmark) for 2018. In the density center of Burgenland, Grinschgl and Ille (personal communication) found a population density of about 1.3 breeding pairs/km2 in 2017 and 1 breeding pair/km2 in 2020. In northwest Weinviertel in Lower Austria, population density was 0.8 breeding pairs/km2 in 2014 and 2.5 breeding pairs/km2 in its density center (Pulkautal) in 2017. In the Krems area, with 8 breeding pairs/km2, and Wagram, with 10 breeding pairs/km2, density was locally very high in 2017.

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5.5.15 Czech Republic 5.5.15.1 DISTRIBUTION The Little Owl was the most abundant and widespread owl in Bohemia in the 1940s (Stastny et al. 1996). However, in recent decades its distribution range has clearly been reduced. Between 1973–1977 and 1985–1989, the number of occupied squares decreased by 43% (Stastny et al. 1996; each survey square was 132 km² in size). The Little Owl’s highest abundance was recorded in areas up to 500 m elevation. The main populations live south of Plzen town, in the Labe valley near Decin town and in Ohre valley near Lovosice town. In southern Moravia, which was quite densely inhabited by owls in the past, just a few pairs remain. The Little Owl breeds mostly in farm buildings (55.7 %), followed by residential buildings (39.1 %), industrial buildings (2.1%) and churches or castles (1.5 %) (Chrenková et al. 2017). Breeding in tree hollows is extremely rare. In previous monitoring programs the percentage of unoccupied study areas increased from 0% in 1993–1995 to 59% in 1998–1999 and 66% in 2005–2006 (Schröpfer 1996, 2000, Šálek and Schröpfer 2008). The percentage of unoccupied study areas in our monitoring across the country (63%) is comparable with the last monitoring program in 2005–2006, despite the fact that the total area of Little Owl monitoring increased by about 57%. A contraction in the Little Owl’s range is also shown by the abandoned quadrants (Figure 5.29) compared to Stastny et al. (1996), showing a decline of about 91% of occupied quadrants. 5.5.15.2 POPULATION ESTIMATES Owl numbers have been declining since the 1950s. Between survey efforts conducted in 1973–1977 and 1985–1989, a lack of confirmed breeding records occurred in 43% of the

Figure 5.29 Occupied and unoccupied mapping squares recorded during nationwide monitoring program for the Little Owl in the Czech Republic (2015–2016) and Slovakia (2009–2014).

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surveyed squares (Stastny et al. 1996). In 1985–1989 the population size was estimated at 700–1100 pairs (Stastny et al. 1996). An abundance and distribution survey was carried out in 1993–1995 in the Czech Republic. On the basis of the results from 16 study areas, the population size was estimated at 1000–2100 pairs (Schröpfer 1996). The same area was again surveyed in 1998–1999. A noticeable decline to 500–1000 pairs was recorded (Schröpfer 2000). The main reasons for the decline since 1993–1995 were most probably the severe winters of 1995–1996 and 1996–1997, with long-lasting snow cover. BirdLife International (2004) estimated the total population at 200–400 pairs. During the period 2009–2016, Chrenková et al. (2017) monitored 1968 potential breeding localities across the Czech Republic. In total, the presence of 94 males at 84 localities was recorded in 40 mapping squares, which represented 20.8 % of the mapping squares that were controlled for Little Owls ðn ¼ 192Þ, but only 6.4 % of overall number of mapping squares at the country level ðn ¼ 628Þ. The total breeding population size was estimated at 130 breeding pairs in 2015–2016 (Chrenkova et al. 2017). BirdLife International (2004, 2015) estimated the total population at 200–400 pairs around 2000 and 250–500 pairs in 2001–2012. The European Environment Agency (2021) reported 100–150 breeding pairs in 2007–2018. 5.5.15.3 DENSITIES In total, 16 of 27 surveyed study areas were not occupied; in the remaining 13 areas the average density was 0.012 pairs/km². The highest densities were recorded in western Bohemia south of Plzen town, where the density was 0.145 pairs/km2 (Schröpfer 2000). The average population density in 2015–2016 was 0.09 calling males/10 km². The population density in individual study areas also differed markedly (Figure 5.30) from 1 13

17 24 15

2

14 25

23

22

3 4

5 6

7

Czech Republic

16

19

18

12

21 20 8 9

10

26 28

29

34

46

35 36 31

55 49

33

32

Study areas Population density – calling males/10km2 0 country border rivers 0.01–0.1

48

30 27

11

44

37

41

52 50

47

45

43 40

54

Slovakia 51

53

42

39 38

0.1–0.3 0.3–0.5 > 0.5

N 0 25 50

100

150 Km

Figure 5.30 Distribution of individual study areas and area-specific population densities of the Little Owl recorded during nationwide monitoring program in the Czech Republic (2015–2016) and Slovakia (2009–2014).

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0.02 (study area = 22) up to 0.33 (study area = 23) calling males/10 km² (Chrenkova et al. 2017). 5.5.15.4 TRENDS The national 2015–2016 population density of 0.09 calling males/10 km² (2015–2016) is comparable with the density recorded in 2005–2006 (0.1 calling males/10 km²; Šálek and Schröpfer 2008) but had declined by about 73% compared to monitoring in 1993–1995 (0.33 calling males/10 km²; Schröpfer 1996).

5.5.16 Slovakia 5.5.16.1 DISTRIBUTION The Little Owl is a common breeding species in lowlands and basins of southern Slovakia (Danko et al. 2002). The species is distributed along rivers in north Slovakia too, in several areas up to 600 m elevation. In lowlands it usually occurs between 100 and 300 m. Its typical habitats in Slovakia include small field patches surrounding barns and other agricultural buildings, and villages. These habitats are usually situated at lower elevations – in lowlands and hilly areas. The species avoids forests and big cities. The Little Owl can sometimes be found at the margins of industrial zones surrounded by fields. The highest densities in Slovakia were recorded in the lowlands of eastern Slovakia, the lowest in the basins and hills of north Slovakia. The Little Owl breeds mostly in farm buildings (55.7%), followed by residential buildings (39.1%), industrial buildings (2.1%) and churches or castles (1.5 %) (Chrenkova et al. 2017). Breeding in tree hollows is extremely rare. The Chrenkova et al. (2017) study also indicates that large-scale extinctions and contractions of the distribution have occurred over recent decades, although this pattern was more obvious in the Czech Republic. In particular, the occurrence of the Little Owl was not confirmed in 63% of the study areas in the Czech Republic and 44% in Slovakia. 5.5.16.2 POPULATION ESTIMATES Between 1980 and 1999 the total number of breeding pairs in Slovakia was estimated at 800–1000 pairs; the number of wintering Little Owls between 1980 and 1999 was estimated at 2000–3000 individuals. The population slightly decreased and the geographic distribution decreased by 20% (Danko et al. 2002). BirdLife International (2004, 2015) estimated the total population at 800–1000 pairs around 2000 and 400–700 pairs in 2012. The European Environment Agency (2021) reported 300–600 breeding pairs in 2007–2018. During the period 2009–2016, Chrenkova et al. (2017) monitored 877 potential breeding localities in Slovakia through playback. In total, 231 males at 218 localities in Slovakia were recorded. Occurrence was confirmed in 61 mapping squares, which account for 37.7% of controlled mapping squares (n = 162) and 14.2% of all available mapping squares (n = 429) in the country (Figure 5.29). The average population density of the Little Owl in all study areas across Slovakia was 0.36 calling males/10 km², which is significantly higher than in the Czech Republic (0.09 calling

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males/10 km²). The total breeding population size of the Little Owl was estimated at 550 pairs in Slovakia. 5.5.16.3 TRENDS A slight long-term decline of the total population is evident (Danko et al. 2002). In Slovakia, the lack of long-term data on population dynamics prevents detailed assessment of population density changes. However, the population density in 2009– 2014 (0.36 calling males/10 km²) is markedly lower than densities in 1995–1999 (0.75–0.1 calling males/10 km²; Pačenovský 2002) or local-scale studies performed during the 1980s and 1990s (e.g., 1.1–3.5 calling males/10 km²; Danko et al. 1995). 5.5.16.4 DENSITIES The highest densities in Slovakia were recorded in the lowlands of eastern Slovakia (12–15 pairs/121 km² or 0.09–0.12 pairs/km²), the lowest in basins and hills in north Slovakia (1–3 pairs/121 km²) (Danko et al. 2002). The population density in individual study areas in 2009–2014 (Chrenkova et al. 2017) differed markedly (Figure 5.20). Occurrence was not confirmed in 44% of the research areas. The highest recorded density was 1.19 (study area = 43), the lowest occupied study area (study area = 34) had a density of 0.09 calling males/10 km².

5.5.17 Croatia As of 1991, the population of Croatia was estimated at 6000–8000 pairs (although the data quality for this estimate was not provided; Manez in Tucker and Heath 1994). BirdLife International (2004, 2015) estimated the 2002 population at 500–1000 pairs and 4000–6000 pairs in 2010. The European Environment Agency (2021) reported 4000–6000 breeding pairs in 2007–2018.

5.5.18 Slovenia 5.5.18.1 DISTRIBUTION In 1769, J. A. Scopoli described the Little Owl to science from a specimen collected in Slovenia. In the past, the species was very common and widely distributed in Slovenia (Ponebšek 1917, Reiser 1925). Later a marked decline was noticed and the species vanished from several parts of the country, with the bulk of the population distributed in the southwestern (Mediterranean) and northeastern (sub-Pannonian) parts of the country (Berce 2019). In the southern part of Slovenia there is a hybrid zone between the subspecies A. n. noctua and A. n. indigena (Keve et al. 1960). The Little Owl is mainly a lowland species in Slovenia, below 630 m (Tome 1996a, b). However it has also been found at higher elevations (e.g., from 690–900 m) in the alpine region (Vogrin 2001), but these reports were viewed as reflecting nonbreeding individuals (Božič and Vrezec 2000, Vogrin 2001). The Little Owl (Čuk) is a rare nesting bird now (Berce 2019), most common in the Primorska region, namely in the Vipava valley in the fields of Goriška, in the northern

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part of the Karst and in the Koper hills, which is similar to what was reported by Geister (1995) (Figure 5.31). Individual breeding pairs can also be found in the Tolmin region. Additional records are from Goričko, and in some places in the fields of Drava and Ptuj and in the Celje basin. It is rare in the Ljubljana Marshes, where up to five pairs allegedly nest (Berce et al. 2014) and from where, according to Tomé et al. (2005), it disappeared in the late 1980s, and in Bela krajina, where it appears singly. It is interesting that there are records from Čatež ob Savi near Brežice in May 2016 and from Veržej on the Pomurska Plain in June 2017, as the species had not yet been recorded in Krško-Brežiška (G. Bernard personal communication). In the southern and southeastern parts of the country the species has been reported during the breeding season in the vicinity of Mirna in the Dolenjska region and the vicinity of Veliki Lašče, which is quite distant from other occurrences of the species. Compared to Geister (1995), the species is less widespread, with almost complete extinction in the northeastern part of the country, where it lived in Slovenske gorice, Dravsko polje and Pomurska ravina, Ribniško-Kočevski podolje, Pivka, Dolina Reke and Brkini. The owl also disappeared from Gorenjska. It is a resident of a predominantly lowland and hilly landscape, as the majority of the nesting population (>90%) is found at altitudes up to 400 m. The species lives mainly in agricultural landscapes with tall orchards, shrubs with individual trees, and its occurrence is strongly associated with human habitation, where it nests in hollows, buildings, abandoned buildings and less often in churches (Slana 2000, Štumberger 2000, Surina 2000, Berce and Kmecl 2008, Berce et al. 2014). There is also one known example of nesting in the nest of a white stork, in Župečja vas on the Drava Plain (Bračko and Štumberger 2017). It is a typical open landscape species that avoids dense forest areas and has gradually adapted to living near human habitations such as in Karst, where owls were recorded in areas of the cultural landscape and near human dwellings (Berce and Kmecl 2008).

Figure 5.31 The Little Owl in Slovenia 2002–2017 (European Environment Agency, 2021).

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5.5.18.2 POPULATION ESTIMATES In the second half of the twentieth century the Little Owl breeding population was estimated at 500–800 pairs (Geister 1995). A strong negative trend was noticed in the later part of the twentieth century, especially in northeastern Slovenia (Vogrin 1997), and the beginning of the twenty-first century (Berce 2019). The species is now probably extirpated from the central part of Slovenia. According to recent surveys and population estimates the population is estimated at 100–150 breeding pairs, with the bulk of the population concentrated in the Mediterranean region of southwestern Slovenia (e.g., Karst area; Berce 2019). In the Red Data Book of Slovenia, the species is listed as an Endangered species with intensification of agriculture and traffic collisions listed as the main reasons for the decline and continual threat to its population (Vrezec and Vrh Vrezec 2011, Berce 2019). BirdLife International (2004, 2015) estimated the total population at 150–200 pairs in 2000 and 100–150 pairs in 2002–2012. Berce (2019) and the European Environment Agency (2021) reported 100–150 pairs in 2002–2017. 5.5.18.3 DENSITIES The density in Dravsko polje, south of Maribor town was 0.048 pairs/km² (total area 210 km²) (Vogrin 1997). In central Slovenia, in Ljubljansko barje in an area of about 160 km², Trontelj (1994) estimated the population of Little Owls at 5–10 pairs or 0.03–0.06 pairs/km². Local densities have been found to be low in central and northeastern Slovenia, with 0.03–0.1 pairs/km² (Trontelj 1994, Vogrin 1997), but in southwestern Slovenia in the Karst region in the Mediterranean part of Slovenia are much higher with 0.3–4.0 pairs/km² (Berce 2019).

5.5.19 Serbia and Montenegro 5.5.19.1 DISTRIBUTION The species occurs in the Pannonian peri-Pannonian parts of Serbia (south of the rivers Sava and Danube) and in mountain regions with basins. In Montenegro (Crna Gora) it is found in maritime Montenegro and mountain regions with basins (Stevanović and Vasić 1995). 5.5.19.2 POPULATION ESTIMATES Estimates for Vojvodina (northern part of Serbia – Pannonian Plain) are 1500–2000 pairs. Estimates for the central part of Serbia, excluding Vojvodina and Kosovo are 2500–5000 pairs. The Kosovo region (Kosovo and Metohija) is estimated at 4000–6000 pairs, Serbia (including Vojvodina, Central Serbia and Kosovo) at 8500–13 000 pairs and Montenegro at 1500–2000 pairs (S. Puzovic and D.V. Simic personal communication). An estimate of 5000–10 000 pairs was made for 1962 (Manez in Tucker and Heath 1994). BirdLife International (2004) estimated the total population for Serbia and Montenegro at 10 000–15 000 pairs. BirdLife International (2015) estimated the total population of Montenegro at 1000–2000 pairs in 2002–2012 and of Serbia at 10 300–15 000 in 2008–2012.

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5.5.20 Albania BirdLife International (2015) estimated the total population of Albania at 4000–8000 pairs in 2002–2012.

5.5.21 Greece 5.5.21.1 DISTRIBUTION The species is a fairly common and widespread resident owl in Greece. Little Owls have been familiar birds to people living in Greece for at least 2500 years. They appear in ancient Greek art and in classical times they were associated with the goddess Athena. They still breed locally within Athens and other urban centers, e.g., Lamia, Chalkis, Eubä, Parnas, Zygos and Peleponnese Mountains, though they are more typically found in rural areas. They occur widely over the whole mainland and on most islands, i.e., the Ionian and Aegean Isles, the Cyclads and Naxos (Schönn et al. 1991), in a wide variety of open habitats, including farmland, phrygana and the surroundings of villages and shepherd’s huts (Eakle 1994). Little Owls have been recorded as high as 1650 m on Mount Oiti (Handrinos and Akriotis 1997) and occur at relatively high elevations in other areas, provided suitable open habitat is available. It appears that Little Owls have declined since around 1970 (Cramp 1985). This is most evident in agricultural areas, where the increased use of insecticides has reduced their food supply, and in coastal areas, where urbanization has resulted in increased disturbance and loss of habitat, such as derelict buildings. 5.5.21.2 POPULATION ESTIMATES Although they have been a protected species for many decades, they are disliked and persecuted in many rural areas due to a superstitious belief that their call is a bad omen. However, despite this level of undocumented background impact, the owls remain quite numerous and widely distributed. Their total population ranged between 5000 and 15 000 pairs in the 1990s (Handrinos and Akriotis 1997). BirdLife International (2004) estimated the total population at 5000–15 000 pairs. BirdLife International (2015) estimated the total population at 5000–15 000 pairs in 2008–2012. The European Environment Agency (2021) reported 5000–15 000 pairs in 2007–2018.

5.5.22 Cyprus Considered a common but decreasing species, with 2000–4000 pairs as of 1988 (Manez in Tucker and Heath 1994). BirdLife International (2004) estimated the total population at 5000–15 000 pairs. BirdLife International (2015) estimated the total population at 4000–10 000 pairs in 2006–2012. The European Environment Agency (2021) reported 4000–10 000 pairs in 2007–2018.

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5.5.23 Hungary 5.5.23.1 DISTRIBUTION The spatial distribution of the Hungarian Little Owl population is well known but data are lacking on temporal changes/tendencies in population size. The species is present throughout Hungary, especially east of the river Danube (Schönn et al. 1991, Gorman 1995) (Figure 5.32). The core population inhabits the Hungarian Plain, although breeding pairs can be found in hilly parts of the country, in smaller densities (Gorman 1995). Typical nesting sites are the lofts of farmhouses and barns (Schmidt 2000). The core population of Little Owls is located in the Great Plain. The bird is found almost everywhere in the plains and hills, but it avoids the higher, closed, forested areas of the midmountains. It is typically connected to the lowland landscape, where it prefers grazed grasslands and the immediate vicinity of livestock farms. It is less common in the southwestern part of the country. Based on probability modeling of occurrence (Hámori 2019) for the nesting period, the species is the most common between the Danube and the Tisza and in the Trans-Tisza. Within these geographical areas, the most significant breeding population is located in Bács-Kiskun, Csongrád, Békés, Hajdú-Bihar and Szabolcs-SzatmárBereg counties. It is also common in the Kisalföld, in the outskirts of western Hungary, in the eastern areas of the Transdanubian Mountains and the Somogy Hills, in the Mezőföld and Cserehát regions. The probability of occurrence is increased by the proportion of different agricultural areas and adjoining sandy steppe, saline and closed grasslands, as well as the number of buildings in the given area (Hámori 2019). 5.5.23.2 POPULATION ESTIMATES The population was estimated at 2000–2500 pairs as of 1994, and is probably stable again after a decline (Gorman 1995). BirdLife International (2004) estimated the total

Figure 5.32 Little Owl distribution in Hungary (after Nagy in Szép et al. 2021).

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population at 1500–2500 pairs. BirdLife International (2015) reported 1500–2500 pairs during 2000–2012, the European Environment Agency (2021) reported 3000–4000 pairs during 2007–2018. The estimated size in 2021 was approximately 1500–4000 breeding pairs, and the population tendency was considered to be negative (MME Nomenclator Bizottság 2008, Hámori and Csortos 2016, Hámori 2019). 5.5.23.3 DENSITIES Density modeling shows the highest densities in the Transdanubian Mountains, the northern periphery of the Northern Central Mountains, the Upper Kiskunság and other parts of the Danube–Tisza region, as well as in the Trans-Tisza region. In the central and southern parts of the latter, as well as in the northern part of the Bereg Plain, the density data show close to 2 individuals/km². Densities increase with the proportion of agricultural land characterized by arable land and other permanent crops, as well as with the proportion of closed grasslands, but decreases somewhat with higher forest cover in the given area and sandy soil cover in the habitat.

5.5.24 Bulgaria 5.5.24.1 DISTRIBUTION Ignatov and Popgeorgiev (2021) presented historical and newly collected distribution data in order to update the distribution map with the help of members of the Bulgarian Society for the Protection of Birds (BSPB) – consisting of unpublished field observations covering the entire Bulgarian territory. All previously published data were reviewed and used, to give an updated view on the presence of the species. The distribution is shown in Figure 5.33 in a 10
10 km grid. Of a total of 1240 squares, 1126 were found to be occupied, 398 had been published and re-confirmed, 8 were new records and 720 were published but not re-confirmed. The elevation distribution reveals that most Bulgarian Little Owls are breeding up to about 300–400 m a.s.l. No more than 9% prefer higher altitudes from 400 to 800 m. Just 5% are above 900 m and several localities up to about 2300 m, mainly in mountain huts. Ignatov and Popgeorgiev (2021) confirmed that the species prefers to breed and winter in human settlements (90%). The species is widespread everywhere in Bulgaria occurring up to about 900 m a.s.l. (Patev 1950, Simeonov 1983), about 98% in human settlements (Ignatov 1993), mostly in villages and cities, such as in 1983, in Sofia (capital of Bulgaria), with 140 reported breeding pairs (Iankov 1983). In the following decades, no changes have been reported, including the last previously published data from the Atlas of Breeding Birds in Bulgaria (Iankov 2007). The population of Little Owls is found to be occupying villages, towns and the city of Sofia (Iankov 1983, Simeonov 1983). There are many breeding pairs within the villages and outside as well in the regions of the middle part of the Struma valley, and the valleys of the rivers Russenski Lom, Provadiiska, Rossitca, Suha Reka, Ogosta, Kamchia, Arda and Iskar. For regions like lowland mountains – Eastern Rhodopi Mountain, Strandja Mountain and Southern Dobrudja – most breeding pairs are found in villages. The species is widespread from 0 to 2300 m a.s.l. Most territories are around 400 m a.s.l.; 95% of the population is

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(B) 23˚0'0''E

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Figure 5.33 (A) Distribution of the Little Owl in Bulgaria (after Hristov and Stoychev in Iankov (2007)). (B) Distribution of Little Owl in Bulgaria, showing published data, confirmed data and newly collected data in the standard 10
10 km UTM grid covering Bulgaria (1240 grid cells) (after Ignatov and Popgeorgiev 2021).

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(C) N

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Figure 5.33 (C) Probability of occurrence of Little Owl in Bulgaria using Maxent (after Ignatov in press).

found up to 800–900 m a.s.l. (Simeonov 1983, Ignatov 1993). One confirmed record of breeding at about 2300 m has been published (Simeonov 1983) and there are four new records (Rhodopi Mountain – 2, Vitosha Mountain – 1 and Central Balkan range – 1) in the mountains, including one at an altitude of 2400 m on Pirin Mountain. More than 50% of the population is breeding at 0 to 400 m in villages on the Black Sea coast, low mountains villages and those around river valleys. There are just a few pairs breeding in high mountains, in mountain huts – on Rila Mountain (Partizanska poliana), Pirin Mountain (Banderitca), Rhodopi Mountain (Perelik and Persenk) and Stara Planina Mountain (Sinanitca). In the autumn–winter period, the highest place that the species has been recorded is 1100 m a.s.l. Birds inhabiting settlements do not usually displace for winter. Most of the owls leaving their breeding areas are young birds or those breeding outside of the settlements. Ignatov (in press) modeled the potential distribution and ecological requirements of Little Owls within part of its range using MaxEnt. The Environmental Niche Model had a high degree of predictability (AUC >0.902). Ignatov estimated that suitable habitats comprised 90.08% of Bulgaria. The climate changes are affecting the distribution, i.e., the vertical distribution of the species expanded by 100 m. With a high number of breeding pairs relative to elsewhere in Europe, Bulgaria has an opportunity and obligation to help preserve the species.

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5.5.24.2 POPULATION ESTIMATES Nankinov (2002) characterized the Little Owl population in Bulgaria as exceeding 10 000 pairs. In 1982 about 140 pairs were encountered in Sofia (Iankov 1983). According to Kostadinova (1997) the breeding population was estimated at 4000–10 000 pairs. BirdLife International (2004) estimated the total population at 5000–8000 pairs. BirdLife International (2015) reported 10 000–14 000 pairs during 2005–2012 and the European Environment Agency (2021) reported 5000–8000 pairs during 2013–2018.

5.5.25 Romania The Little Owl is the most common owl species in the country. It can be found throughout the country with the exception of the forested mountainous areas. As an adaptable species, the owl can be found regularly in villages and towns. In Bucharest the species breeds in the Opera building. The species occurs at up to 800 m (Schönn et al. 1991). 5.5.25.1 POPULATION ESTIMATES The population is estimated at 20 000–40 000 pairs and was considered stable as of 1988 (Manez in Tucker and Heath 1994). BirdLife International (2004) estimated the total population at 40 000–60 000 pairs. BirdLife International (2015) estimated the total population at 15 000–40 000 pairs in 2001–2013. The European Environment Agency (2021) reported 15 000–40 000 pairs in 2014–2018.

5.5.26 Moldova 5.5.26.1 DISTRIBUTION The Little Owl is one of the most widely distributed owl species in Moldova. It is also considered the most numerous of the nocturnal raptors (Ganya and Zubkov 1975). In parks of Askania-Nova, Little Owls willingly occupy the empty nests of Magpies, Pica pica, in insular forests in waterless valleys with groves of the white acacia, far from human dwellings. On the plot at the site “Florike,” on an area of about 50 ha, about 100 Magpie nests were counted and Little Owls were nesting in 42 of them, as if in a colony (Uspensky 1977). 5.5.26.2 POPULATION ESTIMATES The population was estimated to be 5000–7000 pairs in 1988 (Manez in Tucker and Heath 1994). BirdLife International (2004, 2015) estimated the total population at 3200–4200 pairs. 5.5.26.3 TREND Both the short-term and long-term trends are stable, with casual fluctuations that do not influence the overall trend.

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5.5.27 Turkey 5.5.27.1 DISTRIBUTION The Little Owl is a common and widespread species throughout the country with high densities in natural steppes and villages throughout central and eastern Turkey (Ornithological Society of Turkey 1969, Eakle 1994). It is less common to rare in forested areas, e.g., along the Black Sea coast. Due to its common status the species has not been mentioned in recent Turkish Bird Reports (Ornithological Society of the Middle East and Central Asia, OSME). However, Kasparek (1992) reviewed the species as a widespread, common breeding resident in nearly the whole of Turkey, only local in the Black Sea Region and other coastal regions. Further, it was mentioned that the species is rare in alpine areas, though it had been recorded up to 4400 m. In Aegean and Mediterranean coastal areas the species has been recorded scarcely and is mainly confined to villages with surrounding agriculture. However, it is again more commonly found at higher elevations where rocky habitat, macchia and extensive agriculture are prevalent. These studies also revealed that the Little Owl is certainly much more common than estimated (E. Vaassen personal communication). Local populations of the Little Owl as well as the other insect-eater, Eurasian Scops Owl Otus scops, have nearly disappeared from some habitats (villages and ruins) in the Göksu and Çukurova Deltas in southern Turkey, probably due to the massive application of insecticides (E. Vaassen personal communication). 5.5.27.2 POPULATION ESTIMATES Kasparek and Bilgin (1996) estimated in their Checklist of Turkish Vertebrates that the total Little Owl population was 5000–50 000 pairs. More recent field studies have revealed that the owl is certainly much more common than estimated and therefore a population of 30 000 pairs for the whole of Turkey (782 700 km²) is likely to be the absolute minimum (E. Vaassen personal communication). Estimates for Turkey may prove to be very low, given the density of 500 pairs in 80 km² for Emirdag. The national population may reach 200 000–250 000 pairs (E. Vaassen personal communication). BirdLife International (2004, 2015) estimated the total population at 300 000–600 000 pairs in 2000–2013. 5.5.27.3 DENSITIES Recent field studies have revealed that the species is locally very common, with densities of 8–10 pairs/km² in rocky highland areas with marginal cultivation. Similar densities have been located in the surrounding districts of large cities like Ankara and Konya, where building sites and patches of wild-grown steppe are prevalent (Vaassen 2000).

5.5.28 Poland 5.5.28.1 DISTRIBUTION Until the end of the 1960s, the Little Owl was one of the most common owls in Poland (Taczanowski 1882, Sokołowski 1953). In the 1960s, one or two pairs were nesting in

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almost every village in the area of Legnica and Leszno in southwestern Poland (Tomiałojć 1972, Bednarz et al. 2000). The first data concerning the decrease in population numbers of the Little Owl appeared in the 1970s and 1980s when it was considered to occur generally in small numbers, and only locally in medium numbers (Tomiałojć 1990). The disappearance of this species started in western Poland. In the Gorzów Wielkopolski Region, this bird was relatively frequently observed in the 1970s, whereas at present it is practically extirpated (Jermaczek et al. 1995, A. Jermaczek personal communication). A similar situation is observed in the Poznań Region of westerncentral Poland and the Silesian Region of southwestern Poland, where the Little Owl currently occurs in very small numbers (Dyrcz et al. 1991, Bednarz et al. 2000). The tendency towards the gradual disappearance of the species from western Poland was noted in the West Pomeranian Region of northwestern Poland, where at present there are probably only two nesting sites remaining (R. Kościów personal communication). In the nineteenth century the Little Owl occurred in about 130 larger and smaller towns in Poland, and more recently, from 1990–2000, it inhabits over 60 towns, mainly in southern and southeastern Poland (Grzywaczewski and Kitowski 2000). In Poland, the Little Owl mainly occurs in cities and upland areas, i.e., the uplands of Lublin, Cracow, Cracow-Czestochowa and the Sub-Carpathian Highlands. The cities and rural areas located in these regions of south and southeastern Poland can be considered the last strongholds for this species (G. Grzywaczewski personal communication). 5.5.28.2 POPULATION ESTIMATES The species is scarce in most areas, with marked declines after severe winters (Tomiałojć 1976). Based on the available information, the number of Little Owls in Poland was estimated at 1000–1500 breeding pairs in 2003 (Grzywaczewski 2006). Little Owl estimates in different regions of the country are given in Table S5.7 and Table S5.8. Detailed data in the 1990s indicated 10–20 pairs in the Białystok Region of northeastern Poland (M. Polakowski personal communication), 150–200 pairs in the Lublin Region of southeastern Poland (G. Grzywaczewski unpublished data), 10–100 pairs in the Łódź Region of central Poland (R. Włodarczyk personal communication); 50–200 pairs in the Cracow Region of southeastern and southern Poland (K. Kus personal communication) and 120 pairs in the Radom and Kielce Regions of south-central Poland (J. Tabor personal communication). BirdLife International (2004) estimated the total population at 1000–2000 pairs. BirdLife International (2015) reported 500–1000 pairs during 2008–2012 and the European Environment Agency (2021) reported 500–1000 pairs during 2007–2018. Population estimates in 1985–2004 were 1000–2000 pairs (Chylarecki and Sikora 2007), in 1999–2000, 1000–1500 pairs (Grzywaczewski 2006), in 2008–2012, 500–1000 pairs (Chodkiewicz et al. 2015), in 2013–2018, 500–1000 pairs (Chodkiewicz et al. 2019) and in 2020, 1400 pairs (Wilk et al. 2020). 5.5.28.3 DENSITIES In the 1980s, the average density of the Little Owl population in the agricultural landscape was 0.17 territories/km². A relatively rapid change took place in the 1990s,

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when population density dropped to 0.07 territories/km². In 2004 in urban areas, especially in southern and southeastern Poland, an increase was observed in the owl population density to 0.26 territories/km². In Chełm, southeastern Poland, the density of Little Owls is among the highest in Poland, reaching on average 0.4 territories/km². However, after the snowy and frosty winter of 2001–2002, the density dropped to 0.22 territories/km² (G. Grzywaczewski personal communication). In the Kutnowska and Łowicko-Błońska Lowlands (central Poland, a total area of 4352 km2) in 2016–2018 the density varied from 0.6 to 4.0 territories/10 km2. Little Owls inhabit vast areas of intensively used farmland (Jabłoński 2019) (Table S5.9).

5.5.29 Russian Federation There have been substantial changes in the political boundaries of the former USSR, complicating analysis of the older literature on the Little Owl. Below, we briefly describe the owl distribution in the former USSR, and then the owl situation in the respective countries. In the European territory of the former USSR, the Little Owl is distributed mainly in anthropogenic landscapes, in southern Kazakhstan and Middle Asia, mainly in the deserts, dry steppes and in mountainous regions. From the western border the species spreads eastward to the Zabaikalie (Trans-Baikalia) (Sretensk). To the north it reaches Lithuania and Latvia (in Estonia the species is a vagrant bird), Pskov, Moscow, Ryazan Region, Kazan, Buguruslan, Orenburg, from where the border stretches via central Kazakhstan to Zaisan Lake. Further eastwards the species occurs only in isolated populations in the southeastern Altai (Chuiskaya steppe), in Tuvinskaya (Tyva Autonomous Soviet Socialist Republic) and in Trans-Baikalia (Selenginskaya Dauria, Aginskaya, Borzinskaya and Nerchinskaya steppes). In Tien-Shan and the Pamir, the Little Owl breeds at high elevations (up to 4200 m). The southern border of the Little Owl’s range is situated outside the borders of the former USSR (Ivanov 1976). In Russia, the Little Owl is resident, or rarely migratory. The total number in European Russia is estimated to be 10 000–99 999 pairs (Mishchenko 2004). BirdLife International (2004) estimated the total population at 10 000–100 000 pairs. BirdLife International (2015) reported 50 000–70 000 pairs during 2008–2012. While there is some information on owls moving northwards along human-transformed areas, fluctuations in owl numbers are difficult to determine, and some researchers report that the population is currently decreasing in Russia. The population in the Republic of Bashkortostan (Karyakin 1998) is estimated at 10 breeding pairs, with winter numbers at 10–50 individuals. At least 10–15 pairs breed in the whole of the south of the Kaliningrad Region (Grishanov 1994). The Saratov Region of 100 000 km² likely supports about 200–300 pairs (A. Antonchikov personal communication). At present the species is comparatively stable in the Republic of Dagestan, and in some places can even increase due to an increase in human-transformed landscapes in the lowland regions of the Republic and restoration of formerly abandoned cattle-farm complexes. In the Lower Cis-Volga River area Zav’yalov et al.

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(2000) illustrated the intra-year dynamics of abundance for two different environments of Saratov city. For 1993–1998, they found Little Owl densities in old apartment buildings and the forst-park zone to be respectively 0.2 and 0.05 individuals/ km² in winter, 0.1 and 0.2 in prespring, 0.3 and 0.3 in the prenesting period, 0.6 and 0.4 during nesting, 0.5 and 0.4 postnesting and 0.3 and 0.2 for the migration period (Zav’yalov et al. 2000).

5.5.30 Kaliningrad Region As a whole, for eastern Prussia, the Little Owl is considered a rare breeding species, whose numbers decrease markedly as a result of severe winters (Grishanov 1994). Population densities increase slightly from the northwestern to the southeastern parts of the region (Tischler 1941). At present, the status in the Kaliningrad Region looks similar to that occuring before 1940, where the Little Owl was extremely rare to the south of the Neman River, east of the Gulf of Kursiu (Courish Gulf ) and on Samland Peninsula, and was slightly more common in the central part of the region. In the south, the species occurs most frequently along the border with Poland.

5.5.31 Republic of Dagestan 5.5.31.1 DISTRIBUTION The Little Owl is resident in the Republic of Dagestan, spread widely from the shore of the Caspian Sea and lowlands, reaching to 2500 m in the mountain-alpine regions. Due to the arid climate, lowland (northern) desert regions and insignificant forest coverage (7–8% of total area) of the region, the distribution of the owl is noncontinuous. The species inhabits mountain steppes in small numbers, being scattered among other types of landscapes, where it prefers the slopes of southern exposures, with rocks, big and small fragment screes, and outcrops of stones that provide vertical topography. The species often settles near humans that raise cattle and poultry, because the latter supports the concentration of insects and small rodents. In the open landscapes of northern (lowland) Dagestan, including the regions of the central and southern Caspian Sea, it is especially attracted by small human settlements and cattle farms. In the lowlands it inhabits the floodland forests along rivers such as the Terek and Sulak, and forest belts of the tape-grove type. Part of the population inhabits big cities and suburbs, nesting under the roofs of old buildings. While the major part of the population is resident, birds that inhabit the mountain-alpine plots migrate in the autumn–winter period to the foothill and flat regions (E.V. Vilkov personal communication). 5.5.31.2 DENSITIES Densities of Little Owl have been reported at 16–22 individuals/km² in the open landscapes of northern (lowland) Dagestan, including areas of the central and southern Caspian Sea region (Vilkov 2003).

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5.5.32 Republic of Bashkortostan At the northern border of its range, the Little Owl is a very rare breeding species in Bashkiria. Only one breeding site for this species is known in the rocky massif of Belaya River near Kuznetsovskiy khutor. However, it is likely that the number of Little Owls is under-estimated because settlements in the steppe and forest-steppe zones of the Republic have not been investigated (Karyakin 1998).

5.5.33 Republic of Tatarstan In Tatarstan, the Little Owl is recorded mainly in the western and southern districts, i.e., Apostovskiy, Buinskiy, Tetyushskiy, Zelenodolskiy, and also in the Leninogorskiy, Aznakievskiy and Sarmanovskiy districts (Rakhimov 1995). Recent research points at some shift of the border of the Little Owl breeding range in Tatarstan in a northerly direction (Rakhimov and Pavov 1999). This northerly shift seems connected to the rapid rate of forest logging in the area. Following humans, the species spreads into anthropogenic landscapes in the northern half of the Republic.

5.5.34 Republic of Ossetia Komarov (1998) reported winter bird population counts of up to 4.1 individuals/km² in the settlements of the Ossetia Plain.

5.5.35 Tyva (Formerly Tuva) The Little Owl is a rare, probable breeding species in Tyva. In 1983, two specimens were sighted in the upper parts of Barlyk River at Kurgak-Sai. In August of 1984, the species was observed at the Khapshi site and on a macro-slope of the Tsagan-Shibetu Mountain ridge at Oruktyg and Kedyrorug. It is a rare wintering species in Tyva, observed at the Semigorka site (Popov 1991).

5.5.36 Latvia 5.5.36.1 DISTRIBUTION The Little Owl is very rare in Latvia (Lipsberg 1985), locally distributed in different regions of the Republic, most often in the western part. The northern border of the species’ breeding range crosses the territory of the country. According to most authors, in the nineteenth century the species nested more often in Kurland than in Livland (Meyer 1815, Russow 1880). A specific nesting place was found in 1896 and several subsequent years in the Rembate settlement (not far from the Lielvarde settlement) (Sawitzky 1899). In subsequent publications, authors confirm the more frequent occurrence of the species in Kurland than in the rest of Latvia. Nonbreeding season records in the country are from areas surrounding the towns of Riga, Elgava, Dobele and also the settlements Inchukalns, Rembate, Puze Misa, Olainr, Ropaji and Burtnieki (Graubitz

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1983). In the first half of the twentieth century, the species was described as a very rare breeding species (Loudon 1906, Grosse and Transehe 1929, Transehe and Sinats 1936, Taurinsh and Vilks 1949) and found in Kurzem. Breeding was confirmed at only two sites in Rembate, not far from Lielvarde (around 1896 and several subsequent years) (Sawitzky 1899) and near Elgava town (in 1949) (Lipsberg 1985). All other references deal with birds found outside the breeding season and without clear breeding evidence. 5.5.36.2 POPULATION ESTIMATES The Little Owl is considered rare, with an estimate of 10–30 pairs in 1988 (Manez in Tucker and Heath 1994). BirdLife International (2004) estimated the total population at 10–30 pairs. BirdLife International (2015) and the European Environment Agency (2021) reported extinction as of 2007.

5.5.37 Lithuania 5.5.37.1 DISTRIBUTION The Little Owl is a rare resident breeder in Lithuania (Zhalakevichius et al. 1995) and is considered to have a decreasing breeding population. It is assumed that only isolated pairs breed. 5.5.37.2 POPULATION ESTIMATES Manez (in Tucker and Heath 1994) gave an estimate of 10–50 pairs for the period 1985–1988 and considered the population stable. BirdLife International (2004) estimated the total population at 5–10 pairs. BirdLife International (2015) reported 1–10 pairs during 2008–2012 and the European Environment Agency (2021) reported 5–10 pairs during 2013–2018.

5.5.38 Estonia Although the breeding range of the Little Owl reaches western Latvia it has been recorded only once in Estonia. Around 1880–1885, one specimen was shot at Kolovere, Laanemaa district (Stall 1904, Lilleleht and Leibak 1992).

5.5.39 Belarus The Little Owl is a rare resident breeding species throughout all of Belarus (Nikiforov et al. 1997) and is estimated at 400–1000 pairs, with some decline in 1970–1980. BirdLife International (2004, 2015) estimated the total population at 400–1000 pairs.

5.5.40 Ukraine 5.5.40.1 DISTRIBUTION The species is a resident bird in Crimea. Some short-distance winter migrations have been observed. On the southern coast of Crimea the species probably occurs to the east

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of Alushta town. Numbers in steppes and foothills are moderately high and distributed relatively evenly. Along the southeastern shore (south coast) it occurs sporadically. The owls breed in walls of the fortress on Arbat(skaya) Spit (Kostin 1983). 5.5.40.2 POPULATION ESTIMATES Manez (in Tucker and Heath 1994) estimated 11 000–12 000 pairs in 1988, and considered the population to be increasing. BirdLife International (2004, 2015) estimated the total population at 15 000–22 000 pairs in 2000.

5.5.41 Armenia In Armenia, the Little Owl occurs in semi-desert, steppe and mountain-meadow zones. Dementiev and Gladkov (1951) consider the species to be a typical bird for Caucasia. Athene noctua indigena is characteristic of different, but predominantly open habitats, which are situated in the piedemont climatic zone of the river basins of both the Arax and Kura (K. Jenderedjian personal communication). Lyaister and Sosnin (1942) mentioned the species as a resident bird, occuring mainly in places of lower elevation and in the foothills (although up to 2000 m sporadically). It breeds in ravines and gorges, and also in stony ruins of disused settlements and houses. The species has also been observed in gardens. The species was recorded in the Oktemberyan district, in the surroundings of Novyi Shakhvarut, in typical semi-desert, at an elevation of about 900 m (Sosnikhina 1950). It was discovered in the cave of the lava mountain Karkhan (Sosnikhina 1950). The species is distributed in three State Nature Reserves in Armenia (Khosrov, Erebuny and Shikahogh). It was also recorded in rock outcrops of the Goravan sands sanctuary, and in the vicinity of Yerevan (Sokolov and Syroechkovsky 1990). BirdLife International (2004) estimated the total population at 800–1500 pairs. BirdLife International (2015) estimated the total population at 1000–1500 pairs in 2002–2012.

5.5.42 Georgia 5.5.42.1 DISTRIBUTION The Little Owl is a year-round resident in the lowlands, plains, plateaus, foothills and low- and middle-mountain belt of Georgia. It is uncommon in central parts of the country, and common in eastern and southeastern areas. It is more widespread in the Iori plateau, Karthli Plain, Alazani Plain, Gardabani Lowland, in lower parts of the Iori, Alazani, Khrami River valleys, Shiraki and Eldari semi-deserts, Udabno and Kvernaki ridges and in some other points in the Kura River basin. The western boundary of its breeding range remains uncertain. It prefers dry open and semi-open habitats with ravines, precipices and rock outcrops. The species often utilizes older buildings and ruins for breeding. In semi-desert, nests have been found in holes and in cracks in rock precipices. Owls sometimes nest in settlements, including the environs of Tbilisi (A. Abuladze personal communication).

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5.5.42.2 POPULATION ESTIMATES The present Georgian population is estimated at several thousand breeding pairs (4000–4500 pairs at the end of the 1970s, about 3500 pairs in the mid-1980s and 3500–4000 pairs in the middle to late 1990s). During the last 25 years no alarming trends have been detected. Numbers fluctuate annually. A slow decline was registered in some areas in the first half of the 1980s, but the population and distribution have been stable throughout the twentieth century (A. Abuladze personal communication).

5.5.43 Kazakhstan The Little Owl is spread unevenly in Kazakhstan, and occurs sporadically at certain sites. The highest breeding densities are observed in the desert zone of south Kazakhstan, in the regions of south Pribalkhashie, in the foothills of Karatau, in the Syr Daria River valley, along the Aral Sea shore and on the Mangyshlak Peninsula. The northern border for Little Owl nesting sites in Kazakhstan is roughly the 49th parallel, and only in the Ural River basin does it extend up to the 51st parallel. It breeds in Ustyurt, where it is common in breaks in this plateau, but seldom sighted in its central parts. On the Mangyshlak Peninsula it is common, but further northwards, in the northeastern part of the Near-Caspian Lowland, data regarding its presence (or absence) are missing. It is found in the northern Cis-Caspian Sea area, in the lower parts of the Ural and Volga Rivers and further north, and in the Volga–Ural steppes near Urda. Along the Ural River valley it has spread north to the Ilek River mouth. The Little Owl is extremely rare north of Ustyurt, in the desert steppes of the Emba River basin, and in the region of Mugodzhary. The species is well distributed and breeds in high numbers around the Aral Sea. It has been found considerably northwards, i.e., near Chelkar Station and in the Irgiz settlement (Gavrin 1962). Little Owls are common, and at certain sites even numerous, in Kyzyl-Kumy, SyrDaria River valley and in the foothills of Karatau. In the plains of southern Pribalkash’ie, it is spread more evenly and at certain sites it is a common bird. It is also common in the deserts of northern Pribalkhash’ie (Balkhash Lake area), where it normally breeds north of the 48th parallel. Northwards, in the region of the Kazakh small-knoll area, the Little Owl is very rare and is spread extremely sparsely. In the Kyzylrai Mountains it has been found in the stony knolls of Kotur-Kyzyltau (4920’ N), which is the northernmost nest record of the species in eastern Kazakhstan. In the Tien-shan Mountain region, the Little Owl breeds on the slopes of Ugam ridge, and is also found to the south of Chimkent on the Kazgurt ridge.

5.5.44 Uzbekistan The Little Owl is widely spread in Uzbekistan. It occurs at oases, in mountains, semideserts and deserts (Sagitov 1990), in settlements, cemeteries, tugais, sands, on rock outcrops and “kyrs” of Ustyurt (Kostin 1983). The species is considered to be a resident

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bird in Karakalpakia (Ametov 1981). On the northern slopes of the ridge in the lower belt of mountains, the species occurs in low densities (Meklenburtsev 1936). According to Salikhbaev et al. (1970), the species is common in the foothill plains or “adyrs.” It is also common in the entire Zarafshan valley (Bogdanov 1956). Population densities depend mainly on the habitat; in the Kashkadarya valley the owls are more numerous in the foothills, and in clayish and sandy deserts (Meklenburtsev 1958). In the Nuratau Ridge, it is common on “adyrs” and in the foothill plain. It is found in lower numbers in the lower belt of mountains (Salikhbaev et al. 1970).

5.5.45 Turkmenistan The Little Owl is spread throughout the country and occurs all year round. It breeds in rock holes, in rodent burrows, on clayish precipices, in tree hollows, in walls and under roofs of buildings, and in cornices. The distribution and population density of the species are determined by the available food, which mainly consists of small mammals (Bel’skaya 1992). In the western part of Turkmenistan, the Little Owl is a resident species of the southeastern Cis-Caspian Sea area. It has been recorded during mid-January in Krasnovodsk town, below the Nebit-Dag Mountain, and in the Janga settlement (Khokhlov 1995). In Badkhyz, the Little Owl is a common species, distributed throughout the region. The highest numbers are recorded on clayish precipices of the Kyzyldzhar ravine. It is rarest in the desert steppe (Simakin 2000). This species is found throughout the area north of the river bed of Zapadnyi (western) Uzboi. The natural and northern border of the region are the precipices (cliffs) of the Ustyurt Plateau (Kaplankyr chink). The western boundary is the coast of Kara-Bogaz-Gol Gulf and from there, south along the Caspian Sea to Iran (Zarkhidze and Loskutova 1999). 5.5.45.1 DENSITIES In northwestern Turkmenistan, Athene noctua bactriana occurs everywhere. In 1989–1991 the population density in different habitats ranged from 0.4–5.0 individuals/km² (Zarkhidze and Loskutova 1999). In the Repetek Nature Reserve, fluctuating densities were found in Black Saxaul thickets (0.7–1.8 individuals/km²), and in White Saxaul thickets (0.3–1.2 individuals/km²) (Ataev 1977). The global distribution of the Little Owl indicates a presence in the following countries, but no data on the population was available for this project.

5.5.46 Iran Ilanloo et al. (2020) built the first country-level habitat suitability map for the Little Owl and identified the most influential environmental predictor of its distribution in Iran. Using 177 distribution points of species presence data (Figure 5.34) and eight uncorrelated environmental variables, a species suitability habitat model was estimated using the maximum entropy approach (MaxEnt). Results showed that suitable habitats for this species are located in the northwest, parts of the northeast and in southwest Iran.

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Figure 5.34 Little Owl observations in Iran 2012–2021. After GBIF (Global Biodiversity Information Facility) Occurrence Download https://doi.org/10.15468/dl.mnkcux.

Distance to forests, distance to human settlements and distance to agricultural lands are the most important determinants of the Little Owl distribution in Iran. Human migrations from rural areas to the cities and availability of many vacant human settlements surrounded by traditional and semi-modern agricultural landscapes produce suitable habitats for Little Owl in Iran. Results of estimating area of suitable habitats of the species within the agricultural lands showed that 151 718 km² of species-suitable habitat are within agricultural areas in Iran. Most of the suitable agricultural habitats are in northwest and northeast of the country (Figure 5.35). 5.5.46.1 DENSITIES AND POPULATION ESTIMATES When using an average density of one observation per km² we would get a population estimate of 150 000 occupied 1
1 km grid cells for all suitable agricultural areas in Iran.

5.5.47 Tajikistan While the species is widely spread, it is mainly associated with desert landscapes. In the northern part of the Republic it inhabits suitable habitats of Mogol-Tau, in “says” of the Kuraminskiy Mountain ridge, in the Syr-Dar’ya River valley (in the vicinity of Leninabad, Kairak-Kum and further to the border with Uzbekistan), and on the northern slope of the Turkestan ridge (surroundings of Shakhristan, in the valley of Ok-Tanga at 2400 m). It also occurs on the southern slope of the Turkestan Mountain ridge. The species was found in the Iskander-Kul’ Lake area (Ivanov 1940), and in Gissar-Karategin (Popov 1959), where it is most commonly found in the foothills. It is found throughout the Gissar Valley, occupying habitats suitable for nesting (Ivanov 1940, Popov 1959). In southern Tajikistan the Little

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Figure 5.35 Little Owl-suitable habitats within agricultural lands in Iran (after Ilanloo et al. 2020).

Owl nests in the mountains of Rangin-Tau, Aruk-Tau, Ak-Tau, Buri-Tau, Kara-Tau and Khazratishokh, and from the banks of Pyandzh River to the foothills of the Darvaz Mountain ridge. The species has been sighted frequently in the valleys of the Vakhsh and Kafirnigan Rivers, and on the lower portions of the Yakh-Su and Kizyl-Su streams (Ivanov 1940). In Badakhshan the species was found in the upper parts of Shakhdara (Meklenburtsev 1946), in the upper parts of Vakhan-Darya (Bazai-Gumbez) (Ivanov 1940), in the Drukhmatz River valley, and in the surroundings of the Pamir Botanical Garden (Popov personal communication). In all probability, the Little Owl is widely distributed in Badakhshan, but due to small numbers it remains unrecorded by ornithologists in other areas. The species occurs in the southern part of Pamir too, i.e., in the Beik River valley, Ak-Su tributary (Ivanov 1940), in the surroundings of Zor-Kul Lake and the Bash-Gumbez site (Abdusalyamov 1971), and near the Soviet farm “Pamir” on Bulun-Kul (Meklenburtsev 1936).

5.5.48 India (Ladakh) 5.5.48.1 DISTRIBUTION Ladakh is an area through which the line of control (as per the 1972 SIMLA Agreement) between Pakistan and India passes. Although a major part of Ladakh lies in Indian-held Kashmir, a sizeable part is present on the Pakistani side of Kashmir. Further in the north

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above Saltoro Range lies the Siachen Glacier where the two armies are fighting each other at the highest battlefield in the world. The region contains all the Little Owls in India. It lies above 4000 m and includes some extremely desolate areas (N. Paklina and C. van Orden personal communication). Limparungpatthanakij et al. (2017) observed a Little Owl at Se La Pass, Arunachal Pradesh, India, situated near the eastern border of Bhutan (27.51N, 92.11E) at 4200 m a.s.l. The habitat was open with rocky terrain and scattered trees. So far the only documented record in Arunachal Pradesh was a specimen collected in the Mishmi Hills (Baker 1926), about 400 km to the east, the same paper wherein Baker described Athene noctua ludlowi. Further details of the Mishmi specimen are unavailable and it is unclear where exactly in the Mishmi Hills it was recorded, and the season when it was collected. However, the Little Owl is treated as resident in northeastern Sikkim (Ganguli-Lachungpa et al. 2011), with photographic evidence, and the species was recently added to the Bhutan list, based on a record from Nub Tshonapatra in far western Bhutan (Wangdi 2015). The Little Owl may be resident at Se La Pass, as it is known to be resident on the Tibetan Plateau and the nearby mountainous regions of the Himalayas (Grimmett et al. 2011). The subspecies ludlowi is stated to be present throughout the year, at all elevations, between Gyantse and Phari (Baker 1926). Another sighting at the same site, on May 1, 2017, by Jainy Maria, Yann Muzika and Rufikul Islam seemingly supports its likely resident status. Nevertheless, further investigation, and more reports of sightings from the area are needed to confirm its seasonal status (Limparungpatthanakij et al. 2017). 5.5.48.2 POPULATION ESTIMATES The region of Ladakh held some 120 pairs in 2003 (N. Paklina and C. van Orden personal communication). The global distribution of the Little Owl indicates a presence in India, Pakistan, Nepal and Bhutan, but no data on the population were available for this project. However a map of the Little Owl’s distribution in these countries, from Grimmett et al. (1999) is shown in Figure 5.36.

5.5.49 Bhutan The Little Owl has only recently been recorded in Bhutan. The Little Owl is resident in Baluchistan and the trans-Himalayas, living on cliffs and ruins in semi-desert (Wangdi 2015).

5.5.50 Mongolia The Little Owl occurs in natural habitats and anthropogenic environments and is considered rare everywhere in Mongolia. Breeding was observed in the Chentej Mountains near Boroo, near Chudshirt and in the Gobi Desert. Other records are from Somon, Buucagaan, Jarantaj (border with China), Conocharajch-gol, Ulaan-uul, Chvod, Ajmak (southern Gobi) (Schönn et al. 1991). In Mongolia, the Little Owl is considered a rare south-Eurasian species, occuring as a breeding species in the desert mountains and stony deserts of northwestern Mongolia and southeastern Altai

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Afghanistan Iran Pakistan

Kuwait

India

Nepal Bhutan

Bahrain di Arabia

United Arab Emirates

Bangladesh

Oman Myanmar

Yemen

outi

Figure 5.36 Map of Little Owl distribution in India, Pakistan, Nepal and Bhutan (after Grimmett et al. 1999).

(Rogacheva 1988). The Little Owl is probably a vagrant species. The only specimen observed within the borders of the Krasnoyarsk Territory was in 1908 in the Us settlement. Overall, the owl breeds in stony deserts, semi-deserts and dry steppes with separate rocks or stony ridges; in the mountains, it occurs up to 2800 m (Sushkin 1938).

5.5.51 Tibet 5.5.51.1 DISTRIBUTION The Little Owl is common in a large area of northern China (Fu-Min Lei personal communication), and the Tibetan Plateau features some isolated breeding populations above 4000 m in extremely desolate areas (N. Paklina and and C. van Orden personal communication). 5.5.51.2 POPULATION ESTIMATES In 2003, the population of the Tibetan Plateau was estimated at 50 000 pairs after extrapolation from the density in Ladakh (N. Paklina and C. van Orden personal communication).

5.5.52 China The northern border of the Little Owl distribution range crosses northeastern China, the southern goes through Tschajul, Yaan, Daxian, Nanyang to the south of Xinhailian and the Yellow Sea. Qingdqo was registered as the eastern-most point of occurrence (Schönn et al. 1991). Little Owls are mainly distributed in foothills near the forest, prairie and hillside fields. The most suitable habitats in Qishan (34.4 N, 107.6 E) are found to be in open country with scattered trees, earth banks and crevices. The population density differs according to the season; the average density is 0.04 pairs/km² in winter (January and February) and 0.21 pairs/km² in summer (June). The average distance between nests is

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Figure 5.37 Distribution of Little Owl subspecies in China (after Lei et al. 1997).

189 m, and the shortest distance between two nests is less than 100 m. However, they are now rarely found in the Weinan, Meixian and Huxian counties of the Shaanxi Province, and in the Laishui and Yixian counties of the Hebei Province (Figure 5.37).

5.5.53 Korea The most recent record of the Little Owl dates from 1960, when a dead Little Owl was found by one of the employees of the Army Post Exchange in Seoul, Korea. It was said to have been found in the folds of a tarpaulin on a supply truck that had arrived that morning from the Port of Inchon on the Yellow Sea, approximately 40 km west of Seoul. According to Austin (1948), only three records of the species exist for Korea, all based on specimens taken by Won in North Korea (Pyongan Namdo) in November 1931 and February 1932.

5.5.54 Syria The Little Owl can be observed in most parts of Syria. In and around Damascus the species is relatively rare; it may be absent from the intensively farmed land of Ghouta. In the fertile regions around Homs, Hama, Idlop and Aleppo, the species is common and occupies houses, barns and stables. Historical ruins (e.g., Palmira) are a favorite

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breeding place. In the Euphrates River valley and in the desert, the Little Owl breeds in stone piles (Schönn et al. 1991).

5.5.55 Jordan 5.5.55.1 DISTRIBUTION A fairly common resident in the western parts of Jordan, the Little Owl is scarce to rare in the east. It is found in the highlands, rift margins and parts of the Jordan Valley, and in true desert areas. In the highlands, it is fairly common in open habitats with rocks and low vegetation, but never in woods or deep gorges. In the rift margins the species is a common resident from the northern areas, southward to the slopes that face the Dead Sea, where it becomes scarce. It is also rather uncommon in the rift margins/slopes facing Wadi Araba, the Aqaba Mountains and Wadi Rim. In the eastern desert, the Little Owl is common in the areas just east of the highlands, which slope gently towards the eastern desert plateau. This area is characterized by rolling open country with rock boulders and low steppe vegetation. In the eastern desert it is only locally present, usually in the few limestone hills in the flat hammada/flintstone desert and around farms. It is more common and widespread in the northeastern desert, which is covered by basalt stones and rocks (Andrews 1995, Khoury personal communication). 5.5.55.2 POPULATION ESTIMATES The population size is estimated at several thousand pairs (Andrews 1995, Khoury personal communication).

5.5.56 Israel 5.5.56.1 DISTRIBUTION The Little Owl is resident in most areas and is found as territorial pairs during the breeding season. Outside the breeding season it normally occurs as singles, but some pairs remain together throughout the year. Immature birds wander and disperse short distances. The most continuous and dense population occurs along the central mountain range, including Golan, Galilee, Carmel, Shomron and Judea. In Hermon, it is a rare breeder up to 500 m (Figure 5.38). There is a quite dense population in the Jordan River Valley, especially on cliffs along the Jordan River itself. It is more widely dispersed in the northern valleys and along the Coastal and Judean Plains (in the Dan region, mainly in the eastern hills). It is common throughout much of the Judean Desert, mainly northwestern parts, near the Judean Hills. It is almost totally absent in the lowlying arid areas of the Judean Desert, in the Dead Sea Depression and along the Arava. In Negev it occurs continuously, mainly in mountainous regions north of Nahal Paran, in the Makhteshim, Nahal Zin area and in northeastern Negev between Arad and Yeroham. The densest concentration in the desert and semi-desert regions occurs in northwestern Negev, Holot Halutza, Nizzana, Shivta and eastwards to Mashabbe Sade. In the Eilat Mountains and the town of Eilat, the species appears occasionally as a

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Figure 5.38 Little Owl distribution in Israel (after Shirihai 1996).

wanderer or migrant, though a few breeding pairs are scattered in “wadis” (an annually dry riverbed or valley) north of the Eilat Mountains and northwards in the area of Biq’at Sayyarim and Shizzafon. In all parts it breeds mainly outside human settlements or on fringes of villages and towns. A few breed in local enclaves within cities such as

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Jerusalem, where there were 30–40 pairs within 68 km² (0.44–0.59 pairs/km²) in the 1980s and a similar number in Haifa (Shirihai 1996). 5.5.56.2 POPULATION ESTIMATES The total population in Israel was estimated in the 1980s at several thousand pairs (Shirihai 1996).

5.5.57 Arabian Peninsula 5.5.57.1 DISTRIBUTION The Little Owl is a widespread, locally common resident in the deserts of Arabia (Figure 5.39). There is no information to suggest seasonal or other movements and it is generally thought of as sedentary, occuring in all states except Bahrain. It has occurred on Das Island in the middle of the Arabian Gulf, evidence that some dispersal/ movement is taking place. There are a number of records from the periphery of the Empty Quarter, but it appears to be absent from the core area. This is likely due to the

Figure 5.39 Little Owl distribution in the Arabian Peninsula (after M. Jennings personal communication).

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lack of suitable roosting/nesting sites rather than the species itself not being tolerant of hyper-arid environments. The owl is scarce in the highland areas of the southwest, except for the drier eastern fringes. It is resident on Farasan Island, but generally scarce at other coastal sites and is not known from Masirah or Socotra Islands. It is a common bird in the United Arab Emirates, where it features a much higher breeding density than is likely in other states except possibly northern Oman (M. Jennings personal communication). 5.5.57.2 POPULATION ESTIMATES The total Arabian population may be of the order of 5000–6000 pairs. There is no evidence to suggest populations are changing in any way, but the huge expansion in agriculture in central and northern Arabia in recent decades is likely to have allowed many more to breed than did previously. In the United Arab Emirates the population has been estimated at 300–1000 pairs, giving a much higher breeding density there than is likely in other states, except possibly northern Oman. This population includes an estimated 50 pairs at Jebel Hafit on the United Arab Emirates/Oman border. Population numbers in pairs are: Kuwait 50, Oman 1000, Qatar 50, Saudi Arabia 3500, United Arab Emirates 600, Yemen 500, Bahrain – not available (M. Jennings personal communication).

5.5.58 North Africa The species is widespread to the north of the Sahara from Morocco to Egypt, with an extension to the south along the Red Sea coast to eastern Ethiopia and Somalia. The upper elevational limits in its distribution are 700 m in the Beni Aros Mountains, 1100–1200 m in the High Atlas, 1500 m at Touggana, 1250 m at Iframe, 2200 m to the west of Bon Iblanc and above 2000 m near Khenifra (Heim de Balsac and Mayaud 1962). The exact southern distribution range remains unclear in several countries in northern Africa. The species was reported to Bojador Cape (Western Sahara), Ain Najla, Smara, Tifariti, Tarfaia, Seguiet et Hamra and Guelta Zammour. It probably reaches south of Rio de Oro and further to Mauretania. It is believed to occur south of the 30th parallel in Morocco. In Algeria the owl is found even more southerly to Zirara, l’Qued Mya. In Libya, the southern boundary of its range remains unclear, around Tripoli and Cyrenaica. In the southern area of northern Africa, the distribution is made up of isolated population clusters, e.g., around Timbuktu (Mali), the Ahaggar Mountains, Aïr (Azbine), Serin Tibesti, Ennedi and Jebel Marra (Sudan) (Schönn et al. 1991).

5.5.59 Egypt In Egypt, the northwestern border of the Little Owl’s distribution remains unclear. In eastern Egypt, the distribution area covers the delta of the river Nile up to the Sinai, to the Red Sea coast through Sudan and Ethiopia to Somalia. Following the river Nile, the species breeds further south than the Assuan Dam (Schönn et al. 1991).

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5.5.60 Libya While the Little Owl is common in the northern part of the country, the southern limit of its distribution remains unclear, but is probably around the border with the Oubari Desert. In the east, the species is found from Ajadabia to the Egyptian border. The species is believed to breed around Fezzan. Owls observed in Goddua, Traghen, Hun and Sebha confirm the sporadic occurrence and migratory behavior in this region (Schönn et al. 1991). Resident breeders are common in open areas throughout Tripolitania extending, eastwards to the Sirte area (old olive groves and arid, rocky desert) (Isenmann et al. 2016). Further south, breeding is claimed only as probable in Fezzan (occurrences recorded at Al Qurdah, Goddua, Ghat, Hun, Qatrun, Sebha). In Cyrenaica Little Owls were recorded on May 26, 2008 near Lake Ain Azziana, Benghazi and on May 27, 2008 at Old Al Marj and Cyrene. Two birds found dead on a road on January 5, 2011 near Kabao referred to saharae. At Djanet/Algerian Sahara, close to Ghat, the diet included 70% insects and 17% rodents (Sekour et al. 2011).

5.5.61 Tunisia The Little Owl is a sedentary breeding species occuring from the Mediterranean coast to the Sahara Desert. It was considered the most common owl species in Tunisia, occuring in open or scarcely forested areas along fields with walls or rocks (Isenmann et al. 2005). The species is widespread across the country in both the dry, unfertile desert mountains of the south and the green fertile regions of the north. In central and northern Tunisia, the species breeds in olive plantations (Schönn et al. 1991), widely distributed from the coast to the Saharan regions. In 2004, 18 pairs were recorded in a 2 km² area, surrounding a northern village with fields, piles of stones, and occupied and abandoned houses (B. A. Hajer personal communication). A brood of four 1-week-old pulli was observed in Khanget Oum Ali on May 26, 1993 (H. Dlensi personal communication). The diet is mostly insects, scorpions, lizzards and gerbils, in the Thyna salt-pans also bats and birds and in Ichkeul mainly insects (Isenmann et al. 2005). It has been observed as far south as Borj Bourguiba and Dehiba.

5.5.62 Algeria The species is fairly widespread from the Mediterranean coast to deep into the desert, reaching the Ahaggar where it is rare (Isenmann and Moali 2000). There are records of this owl up to 1400–1700 m on the Holm Oak-covered southern slopes of the Aurès, and up to 1600 m on scree and broom slopes in the Djurdjura Mountains. It is less strongly linked to trees than the Eurasian Scops Owl Otus scops, and takes advantage of more open areas with walls, wells, rocks and screes (Isenmann and Moali 2000).

5.5.63 Morocco The Little Owl is a resident breeder in Morocco (A. n. glaux in nondesert areas and A. n. saharae in the desert). It is common and widespread in Rif, the “North Atlantic,”

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Central Plateau and “Mid Atlantic” (Thévenot et al. 2003). It is also locally common in eastern Morocco from the Plains to the Saharan Atlas. It can be found frequently up to 1500 m in the Middle and High Atlas and is rarer above. The owl occurs south of the High Atlas, is common in Souss, Anti-Atlas and “East Sahara” (A. n. glaux, but saharae recorded twice in Tafilalt and once in Souss at Massa).

5.5.64 Western Sahara In Western Sahara, it is locally common along the Atlantic coast in Lower Draa, Tarfaya and south to Boujdour in Saquiat Al-Hamra, but rare inland at Aïn Nakhla, Smara, Tifariti and Aïn Tahla. Rare further south in Oued Ad-Deheb and only reported from near Guelta Zemmour, Sbayera, Negyir and Awserd (22 40’ N) in the far south (Thévenot et al. 2003). The species occurs in good densities in the entire coastal region of Bas Draa up to the Oued Draa valley, e.g., more than 20 birds between Plage Blanche and Foum Assaka (May 15, 1994) and five birds between Ras Oumlil and Aoreora (January 27, 2011). It is less common in mainland Bas Draa with observations in Jbel Bani and Assa (Bergier et al. 2017), and common in coastal Saquiat Al Hamra, with observations for the Tan-Tan plateau, the gueltas of Oued Chebeika, the hinterland of Akhfenir, Rhouiba plateau, Oued Ez Zehar, Khaoui Naam, Ténouchad, region of Khnifiss, Cap Juby, northeast from Tarfaya and Amgriou, south of Sebkha Oum Dba and Oued Khwiy As-Saraq, the Dawra, from the valley of Saquiat Al Hamra to Dchira with pairs along the Laâyoune Lake and the hinterland of the port in high densities. In the interior Saquiat Al Hamra, owls have been observed in Hassi Amit south of Ouarkziz, east of Zag, south of M’Sied, near Abatteh near the Aydar massive, between Laâyoune and Smara, in the valley of Saquiat Al Hamra in Aïn Najla and east of Sidi Ahmed Laroussi, more south between Laâyoune and Bou Kra, halfway between Bou Kra and Guelta Zemmour and in Sbayera. Little Owls are much rarer in northern coastal Oued Ad Deheb, with five birds between Boujdour and Dakhla, one at Lamjayir and one at the mouth of Oued Kraa. They are even more rare to the south, with observations around El Argoub, Gleib Jédiane and Imlili, and very local in interior Oued Ad Deheb in Graret Ouchfegt, Negjyr massive, Tiris, Oued Jenna and Aousserd. The southernmost observation is east of the Boulariah dam (2226’45”N 1431’20”W) on October 21, 2014 (Bergier et al. 2017).

5.5.65 Mauretania The Little Owl is a resident breeder in sandy and rocky locations in Saharan Mauretania from Tiris-Zemmour south as far as 17N (Wadab, Alké Awana). It has not been recorded in Senegal.

5.5.66 New Zealand The Little Owl was introduced to New Zealand by the Otago Acclimatisation Society (Otago Fish and Game Council) in 1906 when 28 birds were imported from Germany

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(subspecies Athene noctua vidalii), hence it is often referred to as the German Owl in New Zealand rather than the Little Owl. They were released in an effort to control the numbers of small introduced birds, which were considered a pest by orchardists. Another 39 owls were brought to Otago and released in 1907, 80 more in 1908 and another 72 in 1910 (14 were released and the rest sold to farmers). All owls were thought to originate from Germany. Some may have been released in North Canterbury. A pair was released in Rotorua on the North Island in 1908. Some were said to have been transferred unsuccessfully to the North Island, possibly after 1908. The species is now widespread in the farmlands of Nelson, Marlborough, Canterbury, Otago and Southland. None appear to exist on the North Island. On the South Island they are to be found east of the main divide, although there have been reports of them in Westland and Fiordland. They are plentiful in eastern Otago, and Otago and Southland contain the greatest number of Little Owls anywhere in New Zealand (C. Sawyer personal communication).

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Chapter Summary Habitat is one of the main drivers of species presence, and it needs to be able to support entire populations of Little Owls year round. For Little Owls, habitats will typically include open hunting ground rich in small prey, hunting perches, day roosts and nest holes, with a benign climate and land management regimes that give reasonable long-term continuity. These habitat aspects can be met within a wide diversity of natural and anthropogenic landscapes. Recent declines in numbers and distributions across much of Europe show that tolerable limits are being exceeded. These results are consistent with the view that agricultural change has influenced birds through changes in food quality or quantity (Benton et al. 2002). In this chapter we review the parameters that are of importance for the species, its prey species and its predators. The favored habitat for the Little Owl varies from the natural landscapes of steppes and arid deserts to anthropogenic areas. The common features are open areas with low grass, perches and cavities in the ground, rocks and trees or buildings. The species avoids forests, fallow land and large parcels of arable land. A mosaic effect seems to be important for Little Owls, due to the use of habitat edges, in particular for the richness of prey found there. The relations between the landscape factors will determine local owl densities and demographics. All quantitative studies available were done on anthropogenic habitats. For natural habitats, only qualitative descriptions were available. We first discuss natural habitats in general terms, then we give an overview of different types of occupied anthropogenic habitats, followed by the actual preference of the species toward certain habitat parameters. The latter studies entail both occupied and unoccupied habitats, while habitat typology studies consider only occupied habitats. Understanding the parameters that have an influence on habitat suitability for Little Owls is not always easy, since some studies yield contrasting results. The reasons for the different outcomes of studies are mostly related to the different local circumstances per study, with the size of the area studied and with the spatial scale at which the research was done. We illustrate contrasting results at different landscape scales. While it is recognized that models are just an approximation of the truth, modeling Little Owl presence with different techniques can help to interpret and understand the behavior of the species at different spatial scales. Multiscale habitat assessments enhance our understanding of habitat selection, especially when combined with long-term demographic data. Further, models allow prediction of habitat suitability and help to illuminate conservation priorities. Interpretation and communication of the results is

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enhanced by transparent and repeatable methodologies. The results of such examinations allow us to view Little Owl habitat use from an array of perspectives, and offer insights into key landscape components and associated management options. In Plates 9, 11, 14–19 (plates ludlowi, orientalis, plumipes, bacteriana, impasta, spilogastra, somaliensis, saharae), we offer illustrations of natural habitats taken in various locations across the Little Owls’ range. We have selected these to reflect important and typical habitat conditions that have been demonstrated to be of significance to Little Owl populations. Readers will easily notice striking differences in ecological aspects of the landscapes used by Little Owls. In Plates 3–8, 10, 13 (plates noctua, vidalii, indigena, sarda, lilith, glaux) we offer illustrations of anthropogenic habitats and habitat elements taken in various locations within the global distribution of the Little Owl. We have selected these to reflect habitat conditions that have been demonstrated to be of significance to Little Owl populations.

6.1 Natural Habitats Natural habitats in moderate and warm European regions, northern Africa and Asia are comprised of ravines, gorges, gullies, walls of river terraces, precipitous cliffs and dry unwooded mountains, as well as dry hilly steppes, semi-deserts, and sandy or clay deserts. The few vertical structures, containing cavities that are available in these habitats are exploited by the species for nesting. In steppe-like areas the species compensates for the lack of these upstanding structures by occupying cavities in the ground dug by mammals. In Morocco, north of the High Atlas, the species inhabits open land, wadi edges, matorral, palm groves, coastal cliffs, inland cliffs and rocky hillsides. At elevations of 2000–2600 m at Jbel Yagour and the western High Atlas, the species occurs on upland meadows with scattered boulders and low herbage. In predesert and desert areas it is found on open, spiny bush-covered slopes (Crassicauletum with Euphorbia), palm and Argan groves, open acacia woodlands, cliffs and embankments (Thévenot et al. 2003). In Somalia the species breeds in holes in steep dry-river banks. Termite heaps are used as perches and to breed in (Schönn et al. 1991). In the Arabian Peninsula, Little Owls are found in rocky or broken country or in open well-wooded areas, spending the day in rock crevices and tree holes. They do not frequent precipitous cliffs and although they have been found up to 2600 m in Yemen and 2200 m in the northern Oman highlands they seem more numerous in nonmountainous habitats (M. Jennings personal communication). In Afghanistan, the species is mostly found in the middle-high mountains and along the valleys in the steppe regions where willows, poplars, tamarisks and loam walls offer breeding sites (Schönn et al. 1991). In Uzbekistan, isolated pairs occupy old wells in the deserts and nest in the holes of rocks, in clayish and sandy deserts, river valleys, on loess precipices and in the hollows of trees (Sagitov 1990). In the desert they nest in the burrows of Great Gerbils Meriones opinus and Thin-toed Ground Souslik Spermophilopsis leptodactylus or in the nests of Rock Nuthatch Sitta neumayer (Zarudnyi 1896). The species probably digs burrows

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independently, as they improve existing burrows at the end of the tunnel, creating an internal room or chamber (Pukinskiy 1977). On the Kazakh Plain, the Little Owl inhabits various habitats, occuring equally often in sandy desert, clayish desert and in semi-desert (Osmolovskaya 1953). The main requirement is the availability of shelter, such as a burrow or deep hole, in which the birds can roost and breed. Most often nests can be found in the vertical walls of wells, in which they use burrows dug by Rollers Coracias garrulus. In sands they settle in abandoned burrows of Steppe Tortoises, foxes and badgers (Spangenberg and Feigin 1936). In the desert zone the Little Owl willingly settles in river valleys with precipitous banks and tugai groves. The link with the cultural landscape and human settlements is different in the separate Kazakh subspecies. With rare exceptions, the desert subspecies A. n. bactriana clearly avoids nesting in settlements, occupied houses and in industrial constructions. The south European A. n. indigena and the Asian mountain A. n. orientalis subspecies more frequently occupy cultural landscapes and human dwellings (Gavrin 1962). In the northern steppes, the species is absent because the tall vegetation inhibits its ability to hunt on the ground (Schönn et al. 1991). In Crimea, the owl is a typical rocky-steppe species and inhabits rocky outcrops in steppes and foothills, shell open mines and coastal precipices (Kostin 1983). The species inhabits the desert mountains and stony deserts of northwestern Mongolia and southeastern Altai (Rogacheva 1988). In Tadjikistan the species occupies bank precipices and also settles in gullies of foothill areas. Loess precipices are the most favorable nesting habitat. In the mountains, the Little Owl breeds in niches of rocks on pebble slopes (Abdusalyamov 1971). In the Volga-Kama territory, the species is widely spread in opensteppe or forest-steppe habitats (Kulaeva 1977). On the Kyzylkum sands, the species inhabits practically all wintering sites on the gray-ground plain and in the depths of sands. The species breeds in small numbers in “ostantsakh” or isolated remains of mountains, occupying empty cavities in the ground (Gubin 1998). In the mountains of central and east Asia the species is found on the treeless and shrubless steppes, where the Little Owl is a clear ground dweller. It has adapted to the environment by mainly roosting and breeding in burrows of Himalayan Marmots Marmota himalayana, which seem to be a limiting factor for the owl’s distribution (Schönn et al. 1991). In Asian desert areas, the Saxaul sand deserts are frequently occupied by Little Owls. In the Mongolian northern Gobi Desert, large undulating sand planes with Saxaul trees (Haloxylon ammodendron) intermingle with steep sand cliffs where holes created by erosion offer nesting cavities. These holes are complemented by burrows dug by mammals like pikas Ochotana, Siesel Spermophilus citellus, gerbils Rhombomys and voles Microtus in northern Gobi (Schönn et al. 1991). Smaller mammals serve as prey for Little Owls.

6.2 Anthropogenic Habitats The essential criteria for Little Owl habitat can be found in many different combinations of landscape parameters. The types of habitat described here reflect only those habitats actually occupied by owls.

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In central Europe, pastures and meadows flanked by pollard trees provide ample nest sites, hunting perches and year-round short herbage with plenty of invertebrate prey. These components reflect optimal habitat and are characteristic of conservative small farming economies (Exo 1983, Schönn et al. 1991). Around the Mediterranean Sea maquis vegetation areas are widespread and widely used by the owls. This vegetation is limited to 3 m in height and features different species of oak (e.g., Quercus ilex, Q. coccifera, Q. suber) that offer holes that are frequently used by the owls. Olive plantations are favored in northern Africa (Schönn et al. 1991). On the outskirts of Ankara (Turkey) the Little Owl inhabits, at very high densities, apartment buildings that are under construction (E. Vaassen personal communication). The species occurs in settlements, rocky gorges, on forest edges, inhabiting solitary buildings and isolated trees with hollows amidst fields in Bulgaria. Modern urban landscapes provide good conditions for the species (Iankov 1983). The Little Owl occupies a great variety of habitat types from sea level up to 1000 m in Portugal. Frequented habitat types include a great variety of agricultural fields with hedges of different types and in certain regions of extensive crop fields with some trees or rocky outcrops. It is found in different kinds of agro-forest systems, mainly the extensive systems of cork and Holm oaks and of chestnut woods. In these habitat types it is normally more common in areas with old trees featuring cavities, especially in cork and chestnut. It also frequents parks and gardens in cities, small towns and villages. In Lisbon it is not a rare species, frequenting the great urban parks and some gardens (L. Reino personal communication). In Spain, the species shows a preference for open habitats, being found in olive groves, cereal fields, orchards, vineyards, vegetable gardens, wastelands, scattered wooded areas and populated areas. It avoids excessively wet zones, dense forests and high mountain habitats (Muntaner et al. 1983, Olea 1997). In Britain, the species is found in agricultural countryside well endowed with hedgerow trees and farm buildings, old orchards in parkland, drained fenland with lines of pollard willows Salix, and marginal landscapes such as industrial waste ground, sand dunes, moorland edges, old quarries, sea cliffs and inshore islands, treeless rising ground and settlements (Sharrock 1976). It is found only infrequently and impermanently within major cities (Sharrock 1976). Old orchards are particularly valuable to Little Owls, and their use is widely recognized (Juillard 1984, Fuchs 1986, Génot 1990c). Even under intensive management, occupancy of orchards by owls may continue, provided a nucleus of old trees remains. In areas of West Flanders densely populated by Little Owls, modern low-stem orchards with integrated fruit growing (reduced pesticide use) offer good habitat when nestboxes are provided. In Iran the most suitable habitats are found in agricultural areas (Ilanloo et al. 2020). Half of Iranian lands are covered with high mountain ranges and large sections of its central areas are covered by arid plains where the owl does not occur. Suitability of agricultural lands was modeled and showed that distance to forests (51.2%), distance to human settlements (16.2%) and distance to agricultural lands (15.5%) were consecutively the most important variables in habitat selection in Iran. Avoidance of forest and

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forest edges was recognized as a response to the presence of the Tawny Owl (Zabala et al. 2006, Michel et al. 2016). Human settlements include villages featuring traditional agricultural lands and traditional and semi-mordern cultivation systems. Ilanloo et al. (2020) found that the species is more commonly observed in human settlements compared to natural areas for breeding. Agricultural lands are mostly used for foraging and rural areas for breeding. Considering the enhancement of immigration from rural to urban areas, vacant human dwellings surrounded by agricultural lands provide suitable habitats. The Little Owl mainly occupies agricultural landscapes with tree lines and farm buildings in New Zealand. When shrubs and bushes are present, the species also occupies mountains of middle to high altitudes. Farmland and plantations with Pinus radiata, poplars and willows offer hunting grounds with commanding perches and breeding cavities. In cities, the owls can easily forage on the ground in parks due to the short vegetation. Around Alexandra, Central Otago, apricot plantations are characteristic habitats. The plantations are mostly surrounded by pine or poplar trees. Near cities, old trees and sand cliffs are occupied when available. Goldmining activities during previous centuries created new cliffs and holes in the landscape (Schönn et al. 1991).

6.2.1 Farmland Heterogeneity The amount of high-quality habitat patches in farmlands, their distribution and the resource accessibility therein play a key role in regulating habitat effects on reproductive success. Heterogeneous habitats offer nonsubstitutable resources (e.g., nest sites and food) and substitutable resources (e.g., different types of food) in close proximity, thereby facilitating landscape complementation and supplementation. Michel et al. (2017) studied how spatial resource separation in homogeneous agricultural landscapes affects reproductive success see Chapter 10). Decreasing farmland heterogeneity constrains population productivity by increasing separation of food resources from nest or roost sites, resulting in low landscape complementation, and reducing alternative food resources, limiting landscape supplementation. Michel et al. (2017) suggest that structural heterogeneity affects landscape complementation, whereas the heterogeneity and management of farmland affect landscape supplementation.

6.2.2 Mosaic-Like Landscapes Landscape heterogeneity is the only determining factor for the species in some areas of France, highlighting the importance of optimal mosaic structure (Ferrus et al. 2002), rather than a minimal occurrence of some landscape elements. Little Owls prefer landscapes in Flanders with intermediate openness while they avoid extremely open (e.g., lakes, dunes, large parcels) and extremely closed (e.g. forests, built-up) landscapes. Mosaic-like landscape structure was found to be more important than the actual land-cover types. The perimeter of the grassland parcels or the number of parcels rather than their area have a positive influence on habitat suitability (Van Nieuwenhuyse and

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Bekaert 2001b). Landscape heterogeneity (convergence of points for three or four areas having different agricultural land uses) and structuring of grassland were related to population density in Austria (Ille and Grinschgl 2001). The number of such parcels per 25 ha had a positive impact on habitat suitability in Deux-Sèvres, western France (Bretagnolle et al. 2001). Spatio-temporal rotation in the management of landscape patterns can offer optimal habitats year-round, as the species can very quickly react to changing environments by shifting its hunting ranges, even beyond its territories (Finck 1990). The species displays a considerable plasticity in its habitat requirements. Plasticity here refers to the capability of the Little Owl populations to remain viable, given the relatively wide range of open and semi-open habitats that it occupies across its 9000 km-wide range. Some research stresses heterogeneity in the habitats that the owl occupies (Van Nieuwenhuyse and Bekaert 2001b). A multitude of habitat typologies for the Little Owl in Europe (Table 6.1) clearly confirms the plasticity of the species in most of the European part of its range. Research results also confirm that the small size of the scale is more important than the actual land use. All typologies feature the essential criteria for suitable Little Owl habitat which is met within a wide diversity of natural and anthropogenic landscapes and ecosystems (Génot and Van Nieuwenhuyse 2002). This heterogeneity illustrates that certain landscape parameters are interchangable. Splitting the habitats into discrete groups or habitat types allows us identify and quantify the number of different habitat typologies and furthermore it allows us to select representative sampling points for surveillance of the Little Owl in its environment. In terms of sustainability of inventory and monitoring actions, most of the resources should go to assessing the main habitat types. Monitoring these types allows the tracking of conditions in an objective, representative and optimal way since both optimal and suboptimal habitats are included and distinguished.

6.3 Habitat Preferences Essential criteria for suitable Little Owl habitat are year-round prey availability, prey accessibility, vertical landscape structures with cavities and limited predation pressure. An optimal mosaic of short vegetation and commanding perches for prey observation, tall vegetation for prey reproduction and availability of secure cavities for roosting and nesting is preferred (Génot and Van Nieuwenhuyse 2002). Habitat preference can be studied through a multitude of statistical methods. Classification methods use information on occupied and unoccupied habitats in their tests. This way the methods look for parameters that best explain the difference between both types of habitats. Regression methods predict the number of pairs or territories as a continuous outcome rather than a probability of occupation or not. Telemetry data use only occupied habitats, but analyses the differences between the used parts of the habitat and those that are not used, to distinguish positive and negative impacts of the habitat features.

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Table 6.1 Overview of clearly distinguished types of occupied Little Owl habitats in Western Europe Author

Region

Types of habitat

Van Nieuwenhuyse and Leysen (2001)

Flanders (North Belgium)

Van Nieuwenhuyse and Nollet (1991)

West-Flanders (Belgium)

Juillard et al. (1992)

Causse Méjean (Lozère, France)

Mastrorilli (2001)

Bergamo (northern Italy)

Semi-open grassland Grassland around farms Cattle-breeding landscape without farm buildings Horticultural landscape Rural areas with cattle breeding Cereals and orchard far away from farms Cattle-breeding landscape in the vicinity of farm buildings Humid pasture areas with many pollard willows Large isolated meadows with very few trees Fields at slightly higher altitude with many farm buildings Pasturelands grazed by sheep with typical mounds of stones “clapas” Hay meadows and cereal fields with “clapas” Abandoned farms with ruined buildings Active farms Disused quarries Linear habitats of coppiced trees (Fraxinus excelsior) Woods and zones with a particularly closed tree cover Urban area including villages and industrial areas Residential area with parks Gardens at the perimeters of the urban areas Arable lands with or without irrigation and cultivated or uncultivated grasslands

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continues

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Table 6.1 (cont.) Author

Region

Types of habitat

Centili (1996)

Tolfa Mountain area (Italy)

Barthelemy and Bertrand (1997) Fajardo et al. (1998)

Garlaban hills (15 km from Marseilles city, southern France) Southern Spain

Loske (1986)

Germany

Ferrus et al. (2002)

Northern Vosges (northeast France)

Open meadows Partially wooded Covered meadows and cultivated (grass)land Suburban area with houses and gardens Undisturbed hill area with low shrubs and rocky patches Marshland Grassland Sunflower fields Olive tree plantations Orchards Urban areas Eucalyptus plantations Orchard meadow Grassland with pollard trees Borders around villages Grassland with solitary trees Isolated farms Bridges Churchyards “Lössgrube” Urban-type Mixed landscape

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Scarpe-Escaut Plain (north France)

Causse Méjean

Ille (1996)

Austria

Blache (2004)

Plaine de Valence; Drôme, France

Pastures (20–40% of the area) and arable land in about the same proportions Arable land, pastures and woodlands are intermingled Arable land and pastures and built-up areas representing the built-up and related areas Arable land and pastures in equal proportions (40–60% of the area) Large proportions of pastures (60–80%) and a clearly lower proportion of arable land (up to 20%) 46% arable land and 17% grassland in Marchfeld 34% arable land, 35% grassland and 11% vineyards northern Burgenland Mixture of fields, farms and isolated houses, hedges, isolated trees and roads Mixture of fields and roads Small-scale mixture of fields, farms and isolated houses, hedges, isolated trees, roads, tree nurseries and urban zones

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6.3.1 Classification Methods Recent studies have clarified the preference of the Little Owl for specific habitat parameters such as areas of land use (e.g., grassland, fields, forest, built-up areas, orchards, surfaces with short/tall vegetation), lengths of linear elements (e.g., roads, tree-lines, fences, field and meadow edges) and absolute number of specific habitat elements (e.g., individual trees, number of cavities, number of perches, number of abandoned buildings) (e.g., Van Nieuwenhuyse and Bekaert 2001b, Génot and Van Nieuwenhuyse 2002). An array of statistical techniques are used to detect actual habitat preferences from the range of conditions that are available in landscapes. All these techniques try to distinguish occupied from unoccupied landscapes and hence they need to be compared. For simplicity, cartographic representations of landscapes are cut into square grid cells. The landscape within each grid cell is then quantified and used for analysis (Ferrus et al. 2002, Blache 2004). The parameter that will be explained is Little Owl presence using observed associations between the landscape and the owls’ occurrence.

6.3.2 Regression Methods Onkelinx and Everaert (2018) modeled the Little Owl distribution and population numbers in a 3500 ha area in 200  200 m grid cells in Gooik, Belgium, to aid the planning process for land re-allocation and optimization. The aim of the model was to explain and quantify the observed landscape factors that have an impact on the Little Owl. Next, the model was used to simulate possible implications of changes in the landscape for the species. In this way different scenarios could be assessed upfront. Playback (Van Nieuwenhuyse et al. 2001e) was used to assess the local owl population. The landscape was quantified as area of forest, high-stem and low-stem orchard, arable fields, fallow land, grassland, hedges, low vegetation, tall vegetation, total parcel perimeters and urban. Strongly correlated variables were removed. The model highlighted an increase in observed owls with increasing area of fallow land, tall vegetation, grasslands, hedges, high-stem orchard or arable field edges. Negative impacts were lowstem orchards, forest and urban areas. Different scenarios of possible land re-allocation plans were scored using the model and the possible impact on the Little Owl was estimated. An ecological status quo scenario (nature values should be equal or better) as a compromise between nature and landscape performed well and even led to small population increases. This plan would secure and improve the most valuable nature areas in the long term and develop a connected ecological network in the whole area. Pollard willow rows, hedges and high-stem orchards would be secured and further restored or extended. The high-stem orchard extension of the plan, aiming at a full restoration of traditional fruit orchards for the nearby Brussels market did not perform well due to over-estimations of the impact of the current orchards in the model. Territoriality which was not taken care of in the model started to play a role in this scenario. The purely agricultural optimizing scenario, where agricultural parcels were taken together and arable lands sometimes exchanged for grasslands and vice versa also performed well. This scenario amplified

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traditional pastoral land use and induced a partial move of the owl population from suboptimal arable-dominated locations towards high-quality grassland and high-stem orchard areas.

6.3.3 Telemetry Apolloni et al. (2018) studied habitat selection and range use of adult owls in relation to landscape configuration, habitat structure and resource distribution via telemetry in orchard-rich Baden-Württemberg, Southern Germany, in a population of about 220 breeding pairs on 250 km². Of all telemetry fixes, 47.8% were located in orchards, 39.2% in cropland, 9.2% in field margins, 10.2% in grassland and 3.5% in other habitat types. The proportion of major habitat elements over the whole study area comprised, on average, 33.4% cropland, 19.1% forest, 17.1% human settlements, 9.8% orchards, 9.7% open grassland, 7.1% vineyards, 2.8% woods/shrubs and 1% other habitats. Comparision of proportions of available habitat elements versus those used shows significant differences. Orchards were by far the most preferred habitat element in the home ranges, with significantly higher values. The same held for habitat patch use, with field margins the second preferred habitat, followed by grassland and cropland. Roads and wooded areas were strongly under-proportionally used.

6.3.4 Cross-Border Comparison Tschumi et al. (2020) compared land cover, land-use intensity and resource availability between plots of highest habitat suitability for Little Owls among two neighboring, but politically separated areas in southwestern Germany versus northern Switzerland. The land cover and land-use richness did not differ between German and Swiss plots, yet there were marked differences in terms of land-use intensity and the availability of resources. Land-use intensity was significantly higher and resource availability lower in Swiss compared to Germand plots. While accounting well for remotely sensed data such as land cover, habitat suitability models may fail to predict land-use intensity and resources across borders. The relationship between geodata used as proxies and ecologically relevant resources may differ according to history, policies and socio-cultural context, constraining the viability of habitat selection models across political borders. Tschumi et al. (2020) stress the need for fine-scale resource assessments complementing landscape-scale suitability models. Conservation measures need to consider the availability of crucial resources and their socio-economic moderators to be effective. The following habitat parameters were recorded for each sampling plot: permanent meadow area, land-use richness (number of different land-cover types), low-intensity meadows (occurrence of permanent meadows of low management intensity, after Jenny et al. 2011), grazing (occurrence of grazed areas), different cutting regimes (occurrence of different regimes), small structural elements (sum of occurrences of dry stone walls, stone piles, stacks of wood, brush piles, hedges, summer houses, unmaintained buidings and equipment shelter buildings), tree cavities (total number of tree cavities >6 cm diameter and >20 cm depth), roosting sites (occurrence of potential roosting sites

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in buildings, pallet stacks, excluding nestboxes, tree crowns and tree cavities), small rodent index (total predicted small rodent traces per ha after Apolloni et al. 2018), number of trees (all trees standing freely, in groups or orchards, excluding trees in hedges), sampling date and cavity occurrence in individual trees (cavities >6 cm diameter and >20 cm depth after Bock et al. 2013). The discrepancy between habitat suitability model predictions and effective resource availability at a fine scale may explain the absence of Little Owls from areas with high suitability scores in Switzerland. The Swiss plots had a reduced occurrence of small structural elements and a decreased structural diversity compared to the German plots. Grazing intensity in the Swiss plots was high, offering low plant diversity and reduced accessibility due to dense and monotonous swards. The likelihood of cavities decreased after reaching a maximum at 53.9 cm (German plots) and 63.9 cm (Swiss plots) diameter at breast height (dbh), suggesting selective removal of large damaged trees. Lower availability of roosting sites and a lower small rodent index in Swiss plots compared to German further explains the difference in ultimate habitat quality. Animal numbers per area are lower in southwestern Germany than Switzerland (45 compared to 65 cows, sheep and goats per km²) resulting in higher intensification pressure in Switzerland. Differences in property rights result in orchards or allotments being owned more often by nonfarmers, resulting in lower constraints for cost-effective management in southwestern Germany. Major socio-cultural drivers contribute to the differences between Germany and Switzerland, symbolized by Swiss farmers’ unwillingness to invest in conservation, often fed by their concerns about being considered unproductive and reduced tolerance towards nonproductive land uses.

6.4 Habitat Suitability Factors Habitats will typically include open hunting ground, rich in small prey, hunting perches, day roosts and nest holes, and with a benign climate and land management regimes that give reasonable long-term continuity.

6.4.1 Prey Accessibility Through Short Vegetation A Little Owl habitat needs to have sufficient food for both territory owners and their offspring. As Little Owls eat live prey (or sometimes recently dead prey), these prey animals also have to be able to live in a sustainable way, maintaining viable populations over time. Besides having prey at their disposal, Little Owls also need to be able to access and catch the prey. As nearly all of the Little Owls’ prey are ground-dwelling species, the owl needs to catch its prey in short vegetation. To catch prey in an energy-efficient manner, the owl uses the “perch-and-pounce” hunting strategy. It also uses the terrestrial “on foot” hunting method. While hunting for rodents and insects, the birds tend to be perched on a relatively low perch (1–3 m) to obtain a commanding view over their immediate surroundings. Once they discover prey, they pounce on it from the perch. Being posted above the ground allows the owls to discover prey visually. Kestrels (Village 1990) and Barn Owls (Shawyer 1998) are able to hunt more in flight rather

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than being perched and have less problems catching prey in tall grass. Due to its limited ability to fly above tall grassland, its nocturnal lifestyle, and its more limited hearing capabilities, the Little Owl is more dependent on its sight for hunting. In Western Europe, earthworms make up an important part of the owls’ diet, allowing it to hunt successfully on bare ground or in short grasslands. Ideal hunting grounds for the species are to be found at the borders of parcels. These borders function as ecotones with a much higher prey diversity than in the center of parcels. Ideal habitats are small-scale pastures with year-round grazing and very small parcel sizes (e.g., 20 cm), independent of habitat type and 70.0% within low grass vegetation (