Hitting the buffers: conspecific aggression undermines benefits of colonial breeding under adverse conditions

Ashbrook, Kate; Wanless, Sarah; Harris, Mike P.; Hamer, Keith C.. 2008 Hitting the buffers: conspecific aggression undermines benefits of colonial breeding under adverse conditions. Biology Letters. 4, pp.

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Colonial breeding in birds is widely considered to benefit individuals through enhanced protection against predators or transfer of information about foraging sites. This view, however, is largely based on studies of seabirds carried out under favourable conditions. Recent breeding failures at many seabird colonies in the UK provide an opportunity to re-examine costs and benefits of coloniality under adverse conditions. Common guillemots Uria aalge are highly colonial cliff-nesting seabirds with very flexible parental care. Although the single chick is normally never left alone, more than 50 per cent of offspring were left unattended at a North Sea colony in 2007, apparently because poor conditions forced both parents to forage simultaneously. Contrary to expectation, unattended chicks were not killed by avian predators. Rather, although non-breeders and failed breeders sometimes provided alloparental care, unattended chicks were frequently attacked by breeding guillemots at neighbouring sites, often with fatal consequences. These results highlight a previously unsuspected trade-off between provisioning chicks and avoiding conspecific attacks, and indicate that understanding how environmental conditions affect social dynamics is crucial to interpreting costs and benefits of colonial breeding.

Item Type: Publication - Article
Digital Object Identifier (DOI):
Programmes: CEH Programmes pre-2009 publications > Biodiversity
UKCEH and CEH Sections/Science Areas: Watt
UKCEH Fellows
_ Biodiversity & Population Processes
ISSN: 1744-9561
Additional Keywords: density dependence, social dynamics, chick neglect, infanticide, environmental change
NORA Subject Terms: Marine Sciences
Ecology and Environment
Date made live: 22 Sep 2008 09:58 +0 (UTC)

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