Lesser Black-backed Gulls Larus fuscus nesting in an inland urban colony: The importance of earthworms (Lumbricidae) in their diet

Abstract

Capsule: Earthworms can be an important food of birds breeding inland and on the coast. Aims: To identify food and feeding sites of Lesser Black-backed Gulls Larus fuscus breeding on buildings in Dumfries, Scotland. Methods: Direct observations were made of feeding behaviour, and 181 regurgitated pellets, obtained from flat roofs where only Lesser Black-backed Gulls nested, were analysed. Food items were identified using standard techniques with microscopic examination used to identify the presence of earthworm chaetae. Results: Lesser Black-backed Gulls breeding in Dumfries fed extensively on earthworms and insects obtained from agricultural land (55% of pellets). They also fed on landfill (23% of pellets) and marine sites (12% of pellets), but they did not take fish or fish offal. Conclusions: Previous studies on the food of large gulls have often overlooked the importance of earthworms because of the lack of macro-remains in stomachs and pellets. New studies are required to establish the general extent of earthworm consumption in these large gulls. © 2008 British Trust for Ornithology.