Urbanisation weakens selection on the timing of breeding and clutch size in blue tits but not in great tits

Branston, C. J. , Capilla Lasheras, P. , Pollock, C. J., Griffiths, K., White, S. and Dominoni, D. M. (2021) Urbanisation weakens selection on the timing of breeding and clutch size in blue tits but not in great tits. Behavioral Ecology and Sociobiology, 75(11), 155. (doi: 10.1007/s00265-021-03096-z)

Abstract

Urbanisation is a globally occurring phenomenon and is predicted to continue increasing rapidly. Urban ecosystems present novel environments and challenges which species must acclimate or adapt to. These novel challenges alter existing or create new selection pressures on behaviours which provide an opportunity to investigate eco-evolutionary responses to contemporary environmental change. We used 7 years of breeding data from urban and forest populations of blue and great tits to understand whether selection for timing of breeding or clutch size differed between the two habitats and species. We found that urban great tits laid eggs earlier than their forest counterparts, but there was no evidence of a difference in selection for earlier breeding. Blue tits, however, did not differ in timing of egg laying between the two habitats, but selection for earlier laying was weaker in the urban environment. Both species laid smaller clutches in the urban site and had positive selection for larger clutch sizes which did not differ in strength for the great tits but did for blue tits, with weaker selection in the urban population. Our results suggest that food availability for nestlings may be constraining urban birds, and that the temporal cues females use to time breeding correctly, such as tree budburst and food availability, may be absent or reduced in urban areas due to lower caterpillar availability. These results have implications for our understanding of the adaptation of wild animals to city life.

• Item Type: Articles
• Additional Information: This work was financially supported by a UK NERC Highlights Topics grant to DMD (NE/S005773/1) and the University of Glasgow.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Dominoni, Dr Davide and Capilla Lasheras, Dr Pablo and Branston, Dr Claire and Griffiths, Mrs Kate and White, Dr Stewart
• Authors: Branston, C. J., Capilla Lasheras, P., Pollock, C. J., Griffiths, K., White, S., and Dominoni, D. M.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Behavioral Ecology and Sociobiology
• ISSN: 0340-5443
• ISSN (Online): 1432-0762
• Published Online: 20 October 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Behavioral Ecology and Sociobiology 75(11):155
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
303242		Unravelling the impact of artificial light at night on circadian disruption, immunity, and infection risk	Davide Dominoni	Natural Environment Research Council (NERC)	NE/S005773/1	Institute of Biodiversity, Animal Health and Comparative Medicine