Colony selection, longevity, and Ring-billed Gull populations: preliminary discussion

TitleColony selection, longevity, and Ring-billed Gull populations: preliminary discussion
Publication TypeJournal Article
Year of Publication1967
AuthorsSouthern WEdward

During three summers (1963-1965) cannon netting techniques were used to capture 898 adult Ring-billed Gulls at the breeding colony. Of these, 7.2% had been banded as chicks in the same colony; 1.3% as chicks in other colonies; 5.8% by me adults in the same colony during 1963 and 1964; and the remainder were unbanded. On the basis of the small number of banded individuals present in the colony, the capture of several birds banded as chicks in other colonies, and the recapture of the same adults, a hypothesis has been established which states that Ring-billed Gulls select their first breeding colony at random from those available within a particular range of latitudes and longitudes. After having once nested in a particular colony the bird usually returns thereto so long as environmental conditions remain suitable. However, limited data indicates that older adults will also, at least on occasion, change breeding colonies. Influencing factors such as band wear, life span, lack of sufficient recoveries have also been discussed. A brief discussion of the selective value of delayed breeding (two or three years after hatching) in gulls is presented.