The food and feeding ecology of the Light-mantled Sooty Albatross at South Georgia

Abstract

The diet of the Light-mantled Sooty Albatross Phoebetria palpebrata breeding at South Georgia is described on the basis of quantitative analysis of thirtyseven food samples from chicks and nine from adults. Squid and krill Euphausia superba were the main components by weight and by frequency of occurrence, although fish were also taken.

Identifiable fish were chiefly myctophids; measurable krill were mature individuals. Of the eleven species of squid recorded, the most important were Mesonychoteuthis sp A (by numbers) and ?Discoteuthis sp (by weight). These species are hardly taken at all by the other two squideating albatrosses at South Georgia. There are few detailed similarities between the squid taken by P. palpebrata at South Georgia and those recorded in an analysis of re- gurgitated pellets at Marion Island.

Frequency of feeding of chicks and observations of birds at sea suggest that P. palpebrata can forage more widely during the breeding season than Black-browed and Grey-headed Albatrosses. Ecological segregation from these is thought to be achieved by a combination of differences in foraging range and area and by differences in the detailed composition of the diet.