Survey of McCormick skua (Catharacta mccormicki) colonies in Southern McMurdo Sound

A survey of McCormick skua (Catharacta mccormicki) to determine the number of breeding pairs was undertaken during the 1987-1988 season as a follow up to a previous survey in the same region during the summer of 1965-1966 by Ian F. Spellerberg. The area surveyed was the snow free areas as far north as Gneiss Point on the western coast of McMurdo Sound, Horseshoe Bay, just north of Cape Royds on the eastern coast, and the southern extent of the region was Cape Chocolate. Only roosting birds were counted. All locations were surveyed on foot with the exception of the smaller Dailey Island and Cape Armitage which were observed from a helicopter. A grid system was used to survey the colonies as the area to cover was large and there was limited time. The field work was recorded with a handheld videocamera (Video 8 film) and in field notebooks which included number of nesting pairs and the number of breeding pairs, as not all bird roosting were incubating eggs.