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Seasonal sexual segregation in two Thalassarche albatross species: competitive exclusion, reproductive role specialization or trophic niche divergence?

Phillips, R.A.; Silk, J.R.D.; Phalan, B.; Catry, P.; Croxall, J.P.. 2004 Seasonal sexual segregation in two Thalassarche albatross species: competitive exclusion, reproductive role specialization or trophic niche divergence? Proceedings of the Royal Society of London, Series B, 271 (1545). 1283-1291. 10.1098/rspb.2004.2718

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Abstract/Summary

Sexual segregation by micro- or macrohabitat is common in birds, and usually attributed to size-mediated dominance and exclusion of females by larger males, trophic niche divergence or reproductive role specialization. Our study of black-browed albatrosses, Thalassarche melanophrys, and grey-headed albatrosses, T. chrysostoma, revealed an exceptional degree of sexual segregation during incubation, with largely mutually exclusive core foraging ranges for each sex in both species. Spatial segregation was not apparent during brood-guard or post-guard chick rearing, when adults are constrained to feed close to colonies, providing no evidence for dominance-related competitive exclusion at the macrohabitat level. A comprehensive morphometric comparison indicated considerable species and sexual dimorphism in wing area and wing loading that corresponded, both within and between species, to broad-scale habitat preferences relating to wind strength. We suggest that seasonal sexual segregation in these two species is attributable to niche divergence mediated by differences in flight performance. Such sexual segregation may also have implications for conservation in relation to sex-specific overlap with commercial fisheries.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1098/rspb.2004.2718
Programmes: BAS Programmes > Independent Projects
ISSN: 0962-8452
Additional Keywords: sexual segregation, niche divergence, seabird, size dimorphism, foraging habitat preference
NORA Subject Terms: Biology and Microbiology
Ecology and Environment
Date made live: 24 Jan 2012 08:36
URI: http://nora.nerc.ac.uk/id/eprint/12343

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