BREEDING SUCCESS AND POPULATION GROWTH IN A COLONY OF HERRING AND LESSER BLACK‐BACKED GULLS LARUS ARGENTATUS AND L. FUSCUS

Summary This paper describes the results of investigations into the factors affecting breeding success of the Herring and Lesser Black‐backed Gulls Larus argentatus and L. fuscus , in the large colony on Walney Island, northwest Lancashire, between 1962 and 1965. These investigations were concerned with the incubation period, and the first ten days after hatching. The survival of chicks to ten days is 67% in Herring Gulls, and 56% in Lesser...