Diet of a breeding population of South Polar Skuas (Stercorarius maccormicki) of the Schirmacher Oasis, Central Dronning Maud Land, East Antarctica

The first detailed study on the diet of a breeding population of South Polar Skuas (Stercorarius maccormicki) at Schirmacher Oasis is based on the collection and analysis of prey remains and pellets from the 2024/2025 breeding season and food samples from previous seasons near active skua nests (n=8) and old breeding territories (n=2). The diet composition of the skua population and its changes in the context of human activity were determined. The diet included five bird species, fish, squid, and food scraps and garbage from Antarctic stations and bases. The diet was dominated by Snow Petrels (Pagodroma nivea), with subdominants being Antarctic Petrels (Thalassoica antarctica) and Adélie Penguins (Pygoscelis adeliae). Native marine fish and squid were likely incidental dietary components, introduced into pellets along with the skuas’ prey. Human activities have influenced the diet of skuas on a population-wide scale by introducing imported food and garbage into their diet. Food waste was found in seven of eight surveyed breeding territories and in one of two old breeding territories. Diet composition and behaviour of skuas in areas of human activity in Antarctica can be used as an indicator of the quality of local human waste management, as well as an indicator of the health of the ecosystem.