Data from: Increasing temperature, not mean temperature, is a cue for avian timing of reproduction
Data files
Sep 22, 2011 version files 16.09 MB
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README_for_Schaper et al 2011 Am Nat file 3 temp 2008.txt
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README_for_Schaper et al 2011 Am Nat file 4 temp 2009.txt
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README_for_Schaper et al 2011 Am Nat file 5 temp 2010.txt
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Schaper et al 2011 Am Nat file 1 laydates and physiology.xls
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Schaper et al 2011 Am Nat file 2 molt.xls
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Schaper et al 2011 Am Nat file 3 temp 2008.csv
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Schaper et al 2011 Am Nat file 4 temp 2009.csv
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Schaper et al 2011 Am Nat file 5 temp 2010.csv
Abstract
Timing of reproduction in temperate zone birds is strongly correlated with spring temperature, with an earlier onset of breeding in warmer years. Females adjust their laying between years to be synchronized with local food sources and thereby optimize reproductive output. However, climate change currently disrupts the link between predictive environmental cues and spring phenology. To investigate direct effects of temperature on the decision to lay, and its genetic basis, we used pairs of Great Tits (Parus major) with known ancestry and exposed them to simulated spring scenarios in climate-controlled aviaries. In each of three years, we exposed birds to different patterns of changing temperature. We varied the timing of a temperature change, the daily temperature amplitude and the onset and speed of a seasonal temperature rise. We show that females fine-tune their laying in response to a seasonal increase in temperature, whereas mean temperature and daily temperature variation alone do not affect laying dates. Luteinizing hormone concentrations and gonadal growth in early spring were not influenced by temperature or temperature rise, possibly posing a constraint to an advancement of breeding. Similarities between sisters in their laying dates indicate genetic variation in cue sensitivity. These results refine our understanding of how changes in spring climate might affect the mismatch in avian timing and thereby population viability.