Changes in over-winter prey availability, rather than winter climate, are associated with a long-term decline in a northern Tawny Owl population

Orlando, G., Passarotto, A., Morosinotto, C., Ahola, K., Karstinen, T., Brommer, J. E., Koskenpato, K. and Karell, P. (2023) Changes in over-winter prey availability, rather than winter climate, are associated with a long-term decline in a northern Tawny Owl population. Journal of Ornithology, (doi: 10.1007/s10336-023-02085-5) (Early Online Publication)

Abstract

Although the associations between climate, food conditions and reproduction in the wild has been the focus of numerous studies in recent years, we still know little about population level responses to climate and fluctuating food conditions in long-lived species and during longer periods of time. Here, we assessed the relative importance of the abundance of the main prey in winter (small mammals), and winter climate on population size and productivity in a Tawny Owl (Strix aluco) population in southern Finland during a 40-year period. We studied how population trends changed over time and in relation to winter weather and small mammal abundance on three levels: total estimated population size, proportion of breeders and population productivity. We identified declining trends in each population parameter over time, as well as directional changes in climate variables and prey abundance. Overall, small mammal abundance was the foremost predictor in explaining the variation in the number of active territorial pairs (population size). Moreover, both prey abundance and winter temperature significantly affected the proportion of territorial pairs that attempted to breed and thereby total offspring production, which reveals the relevance of winter weather conditions for population productivity. These results provide additional support to the view that changes in climate can modify predator–prey interactions leading to functional changes in the food web.

• Item Type: Articles
• Additional Information: The present study was supported by the Academy of Finland (projects 309992, 335335, and 314108 to PK.; project 321471 to JEB) and the Swedish Cultural Foundation (project 168034 to PK).
• Status: Early Online Publication
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Orlando, Giuseppe
• Authors: Orlando, G., Passarotto, A., Morosinotto, C., Ahola, K., Karstinen, T., Brommer, J. E., Koskenpato, K., and Karell, P.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Journal of Ornithology
• Publisher: Springer
• ISSN: 2193-7192
• ISSN (Online): 2193-7206
• Published Online: 02 July 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Journal of Ornithology 2023
• Publisher Policy: Reproduced under a Creative Commons License