Breeding Biology and Ecology of the Brown-Hooded Gull in Argentina

Abstract

THE Laridae breed in a variety of habitats throughout the world. Of the 44 species of gulls (genus Larus), 19 nest exclusively on the ground and 19 others often or sometimes nest on flat ground. Many of the latter species also nest on cliffs and ledges. The adaptations of gulls for nesting on cliffs have been studied in some detail (cf. Cullen 1957; Emlen 1964; Hailman 1965, 1968; Smith 1966). Beer (1966) studied the breeding adaptations of the Black-billed Gull (Larus bulleri) for nesting on unstable river beds. I examined the behavioral and ecological adaptations in Franklin's Gull (L. pipixcan) for breeding in marshes (Burger 1972a). The Brown-hooded Gull (L. maculipennis) is the ecological counterpart of Franklin's Gull in South America (Weller 1967) where it usually nests in the pampa marshes of Argentina and Uruguay although it infrequently nests on dry ground (Wetmore 1926, Olrog 1959, Meyer de Schauensee 1970). Only very general descriptions of the breeding biology of the Brown-hooded Gull are available (MacDonagh 1944, Plotnick 1951, Moynihan 1962). I studied the behavior and ecology of nesting Brown-hooded Gulls in Argentina, placing emphasis on colony and nest site selection, coloniality, synchrony, and interspecific relationships.