Body size and determinants of laying date variation in the Snow Petrel Pagodroma nivea
We studied several determinants of laying date variation and the relationship between laying date and reproductive success in the Snow Petrel Pagodroma nivea . The effects of female body size and condition, year, individual laying period, colony size, mate fidelity, previous reproductive success, an...
| Published in: | Journal of Avian Biology |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2000
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1034/j.1600-048x.2000.310304.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1034%2Fj.1600-048X.2000.310304.x https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1600-048X.2000.310304.x |
| Summary: | We studied several determinants of laying date variation and the relationship between laying date and reproductive success in the Snow Petrel Pagodroma nivea . The effects of female body size and condition, year, individual laying period, colony size, mate fidelity, previous reproductive success, and duration of the pre‐laying exodus on laying date, were investigated during a 3‐year study. The average laying date was 4 December. The laying period was compressed into 10–16 days and was very constant from year to year, both for the population as a whole and for individual females. The laying period of individual females varied from year to year on average by less than one day. Body size explained 24% of the variation in laying dates, with large females laying their egg later than small ones. Laying in large colonies occurred c. 2 days later than in small colonies, mainly because a higher proportion of large females bred in large colonies. There was no effect of mate fidelity, age, body condition and previous reproductive success on laying date, but the duration of the pre‐laying exodus was strongly correlated with laying date. Smaller females had shorter pre‐laying exodus (c. 17.7 days) than larger ones (c. 20.4 days). During the three years of the study reproductive success either increased, decreased or did not vary with laying date. Although body size is not maintained by selection on laying date alone, the genetic body size component of this species suggests that balancing selection on body size may act through laying date. |
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