Seasonal and Regional Variation in the Diet of the Kelp Gull in Northern Chile

Abstract

The feeding ecology of the Kelp Gull (Larus dominicanus) was studied during the 2002-03 breeding season at Coquimbo, northern Chile. Food composition was studied by analyzing pellets regurgitated by Kelp Gulls living in different habitats. Birds breeding or resting near fishing ports used these as their main feeding grounds. Birds breeding on offshore islands fed mainly on intertidal organisms and olives. A comparison between the food of breeders and non-breeding birds during the breeding season showed a difference in diet composition of breeders, who fed more on fish of high energy density while non-breeding birds continued feeding on a wide range of organisms and waste. Observations in a fishing harbor and at sea demonstrated that fisheries waste was an important food source for the birds. The inshore distribution at sea was related to the location of fishing ports and breeding colonies.