Interactions between Herring and Lesser Black-Backed Gulls Feeding on Refuse

The interactions among Lesser Black-backed Gulls and Herring Gulls during the breeding season while feeding on a refuse dump on Walney Island, England were analyzed. Herring Gulls were found to be more aggressive than Lesser Black-backs, and they were equally aggressive toward Lesser Black-backs and Herring Gulls. It is suggested that Lesser Black-backs are more timid than Herring Gulls and avoid being pecked at by them. Most of the Herring Gulls (77%) found their own food, 95% of the Lesser Black-backs stole theirs. In contrast to Herring Gulls, Lesser Black-backs rarely dug for food and those that fed independently (5%) found less food than Herring Gulls. Lesser Black-backs were very efficient in stealing food, mostly from Herring Gulls. It is suggested that the number of Lesser Black-backs feeding on the dump is dependent on the number of Herring Gulls.