Increase in Weight of Herring Gulls While Feeding

(1) Increase in weight while feeding was estimated for each of thirty-two herring gulls from nest weight, monitored automatically, and knowledge of the availability of food in the environment. Weight increase was on average 32.5 g/h eating earthworms, 12.5 g/h at refuse tips, 18.5 g/h at mussel beds and 37.5 g/h eating starfish. (2) Males had higher ingestion coefficients than females at refuse tips. (3) Starfish ingestion coefficients were lower in 1977 than in 1976. (4) Daily existence energy calculated from these figures is plausible at about 2.5 x BMR.