Evidence of intra-specific competition for food in a pelagic seabird

Lewis, S.; Sherratt, T. N.; Hamer, K. C.; Wanless, S.

Abstract

The factors affecting the population dynamics of seabirds have long intrigued biologists. Current data suggest that density-dependent depletion of prey during the breeding season may regulate population size. However, much of the evidence for this has been circumstantial, and the underlying mechanisms are unclear. Here, we show that the per capita population growth rates of northern gannet Morus bassanus at colonies in Britain and Ireland have declined with increasing population size. Furthermore, direct observations reveal that the mean foraging trip duration of breeding gannets is positively correlated with colony size, both among colonies of different sizes in the same year, and within colonies as they change in size. To understand this phenomenon, we have developed a model which demonstrates that disturbance of fish alone can readily generate conditions under which gannets at larger colonies have to travel further to obtain food.

Citation

Lewis, S., Sherratt, T. N., Hamer, K. C., & Wanless, S. (2001). Evidence of intra-specific competition for food in a pelagic seabird. Nature, 412(6849), 816-819. https://doi.org/10.1038/35090566

• Journal Article Type: Article
• Acceptance Date: Jun 27, 2001
• Publication Date: 2001-08
• Deposit Date: Oct 5, 2021
• Journal: Nature
• Print ISSN: 0028-0836
• Electronic ISSN: 1476-4687
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 412
• Issue: 6849
• Pages: 816-819
• DOI: https://doi.org/10.1038/35090566
• Public URL: http://researchrepository.napier.ac.uk/Output/2808000