The Subantarctic Skua Catharacta antarctica has a wide

circumpolar breeding distribution that includes most of the Southern Ocean islands from the Antarctic Continent northwards to the Chatham Islands (Higgins & Davies 1996). The sub-Antarctic islands provide the species with a variety of potential prey captured using a range of feeding techniques including predation, scavenging and kleptoparasitism (Higgins & Davies 1996, Reinhardt et al. 2000). The species is usually migratory, spending the summer on the islands, and then in the winter months dispersing at sea northwards. In some localities where prey is available year-round, particularly in temperate-zone islands such as the Chatham Islands, the Subantarctic Skua may be resident (Hemmings 1990). Little information is available on the diet of the species in the non-breeding season (Furness 1987, Reinhardt et al. 2000) apart from at the Chatham Islands (Hemmings 1990). Macquarie Island (54°40'S, 158°49'E), situated in the Southern Ocean, supports an estimated population of approximately 550 breeding pairs of Subantarctic Skuas during the summer months (Rounsevell & Brothers 1984). There have been no recent total-island breeding counts of that species on the island. The population is typically migratory, with most individuals leaving in March and April. Stragglers persist on the island until the first week of June (Falla 1937, Jones & Skira 1979). The first arrivals occur in late August, and during September numbers rapidly increase. In previous years no skuas have remained on Macquarie Island ove