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Kleptoparasitism in gulls Laridae at an urban and a coastal foraging environment: an assessment of ecological predictors |
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| Authors: | Robert Spencer Yvan I. Russell Benjamin J. A. Dickins Thomas E. Dickins |
| Affiliation: | 1. Faculty of Science &2. Technology, Middlesex University, London, UK;3. School of Science &4. Technology, Nottingham Trent University, Nottingham, UK |
| Abstract: | Capsule: Kleptoparasitism in gulls occurred at a greater rate at an urban compared with a coastal site. Population density and prey size predicted the rate of kleptoparasitism at the urban site. Aims: To investigate and assess the ecological variables associated with kleptoparasitism among gulls at urban and rural sites. Methods: Field observations were conducted at Brancaster (coastal rural) and Billingsgate Market (urban) to examine differences in the rate of kleptoparasitism in mixed-species flocks of gulls. Four key variables (prey size, population density, season and species) were assessed as predictors of kleptoparasitism. Results: Generalized linear models revealed significant effects on kleptoparasitism rate of site, population density and prey size, and two-way interactions between these main terms. Population density and prey size differed significantly between sites, but population density appeared to predict the rate of kleptoparasitism. Conclusion: Kleptoparasitism may well aid invasion and increase the range of environments a gull can tolerate by helping them meet their energy needs in novel environments where normal foraging behaviours are difficult to implement. |
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