Lucyna Halupka, University of Wroclaw
Debora Arlt, Sveriges lantbruksuniversitet
Jere Tolvanen, Oulun Yliopisto
Alexandre Millon, Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale
Pierre Bize, Swiss Ornithological Institute
Peter Adamík, Univerzita Palackého v Olomouci
Pascal Albert
Wayne J. Arendt, USDA Forest Service Luquillo
Alexander V. Artemyev, Institute of Biology KarRC RAS
Vittorio Baglione, Universidad de León
Jerzy Bańbura, University of Lodz
Mirosława Bańbura, University of Lodz
Emilio Barba, Institut Cavanilles de Biodiversitat i Biologia Evolutiva
Robert T. Barrett, UiT Norges Arktiske Universitet
Peter H. Becker, Institut für Vogelforschung Vogelwarte Helgoland (IfV)
Eugen Belskii, Institute of Plant and Animal Ecology
Mark Bolton, Royal Society for the Protection of Birds
E. Keith Bowers, University of Memphis
Joël Bried, Universidade dos Açores
Lyanne Brouwer, James Cook University
Monika Bukacińska, Uniwersytet Kardynala Stefana Wyszynskiego w Warszawie
Dariusz Bukaciński, Uniwersytet Kardynala Stefana Wyszynskiego w Warszawie
Lesley Bulluck, Virginia Commonwealth University
Kate F. Carstens, University of Cape Town
Inês Catry, CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos
Motti Charter, University of Haifa
Anna Chernomorets, Scientific and Practical Centre of the National Academy of Sciences of Belarus for Bioresources
Rita Covas, University of Cape Town
Monika Czuchra, University of Wroclaw
Donald Dearborn, Bates CollegeFollow
Florentino de Lope, Universidad de Extremadura

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Proceedings of the National Academy of Sciences of the United States of America

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birds, climate change, meta-analysis, offspring production


Climate change affects timing of reproduction in many bird species, but few studies have investigated its influence on annual reproductive output. Here, we assess changes in the annual production of young by female breeders in 201 populations of 104 bird species (N = 745,962 clutches) covering all continents between 1970 and 2019. Overall, average offspring production has declined in recent decades, but considerable differences were found among species and populations. A total of 56.7% of populations showed a declining trend in offspring production (significant in 17.4%), whereas 43.3% exhibited an increase (significant in 10.4%). The results show that climatic changes affect offspring production through compounded effects on ecological and life history traits of species. Migratory and larger-bodied species experienced reduced offspring production with increasing temperatures during the chick-rearing period, whereas smaller-bodied, sedentary species tended to produce more offspring. Likewise, multi-brooded species showed increased breeding success with increasing temperatures, whereas rising temperatures were unrelated to reproductive success in single-brooded species. Our study suggests that rapid declines in size of bird populations reported by many studies from different parts of the world are driven only to a small degree by changes in the production of young.


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