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Breeding frequency in Grey-headed Albatrosses Thalassarche chrysostoma

Ryan, Peter G.; Phillips, Richard A.; Nel, Deon C.; Wood, Andrew J.. 2007 Breeding frequency in Grey-headed Albatrosses Thalassarche chrysostoma. Ibis, 149 (1). 45-52. 10.1111/j.1474-919X.2006.00594.x

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Abstract/Summary

Although Grey-headed Albatrosses Thalassarche chrysostoma are usually regarded as biennial breeders, taking a year off following a successful breeding attempt, a small proportion of successful birds attempt to breed annually. This proportion was higher at Marion Island (5.4%) than at Bird Island, South Georgia (1.0%), suggesting that conditions are more favourable at Marion Island. This hypothesis is supported by higher average breeding success and shorter lags following both successful and failed breeding attempts at Marion Island. Factors favouring reproduction at Marion Island may include reduced intraspecific competition (given the much smaller breeding population) and/or more predictable food supply (owing to production of meso-scale eddies associated with the Indian Ocean Ridge). Although annual breeding appeared to increase the risk of adult mortality, with several birds that attempted to breed annually found dead the following year, at least some birds greatly enhanced their reproductive output, with one male raising five chicks in five successive years. Contrary to life-history theory, there was no evidence that older birds were more likely to attempt annual breeding because of declining reproductive value.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1111/j.1474-919X.2006.00594.x
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > DISCOVERY 2010 - Integrating Southern Ocean Ecosystems into the Earth System
ISSN: 0019-1019
NORA Subject Terms: Zoology
Date made live: 13 Nov 2007 14:39
URI: http://nora.nerc.ac.uk/id/eprint/1196

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