A1 Refereed original research article in a scientific journal
Great tits lay increasingly smaller clutches than selected for: a study of climate- and density-related changes in reproductive traits
Authors: Ahola MP, Laaksonen T, Eeva T, Lehikoinen E
Publisher: WILEY-BLACKWELL PUBLISHING, INC
Publication year: 2009
Journal: Journal of Animal Ecology
Journal name in source: JOURNAL OF ANIMAL ECOLOGY
Journal acronym: J ANIM ECOL
Volume: 78
Issue: 6
First page : 1298
Last page: 1306
Number of pages: 9
ISSN: 0021-8790
DOI: https://doi.org/10.1111/j.1365-2656.2009.01596.x
Abstract
5. We suggest that increasingly favourable conditions in winters have enhanced the survival and resulted in the observed increase in great tit breeding density. This may have most concerned young and otherwise low-quality individuals, which also most likely end up breeding in the increasingly occupied low-quality territories. This hypothesis was indicatively supported by increased within-year variation in both laying date and clutch size. The changes could also explain the lack of advancement in laying date as well as the increasing selection for large clutch sizes as the fittest individuals most likely occupy the best territories and lay largest clutches.
5. We suggest that increasingly favourable conditions in winters have enhanced the survival and resulted in the observed increase in great tit breeding density. This may have most concerned young and otherwise low-quality individuals, which also most likely end up breeding in the increasingly occupied low-quality territories. This hypothesis was indicatively supported by increased within-year variation in both laying date and clutch size. The changes could also explain the lack of advancement in laying date as well as the increasing selection for large clutch sizes as the fittest individuals most likely occupy the best territories and lay largest clutches.
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