The White-capped Albatross of Albatross Island: Numbers and Breeding Behaviour

Abstract

Information on the known breeding and oceanic occurrence of the three subspecies of Diomedea cauta is summarized. Observations on the White-capped Albatross D.c. cauta made during a ten-day visit to Albatross Island, Bass Strait, in late January 1973 are reported. The probable breeding cycle is outlined. The island's breeding population has increased during this century; there were about 400 nests in 1894, 300 in 1909, 700 in 1960, and in 1973 about 1,500 chicks hatched. Observed mortality of nestlings was associated with infestations by ticks in a few areas. Courtship and agnostic displays suggest that this species is correctly grouped taxonomically with the four other mollymawks. Maintenance of nests and feeding of chicks were as described for other albatrosses. At night many adults, including some that may have been pre-breeders, occupied the colony, dispersing in the molrning to feed. Dark-billed birds, presumed to be one to two years old, were seen only at sea.