Sheathbills (with their two species) are the only bird family with a breeding range that falls entirely within the Antarctic and Sub-Antarctic. In this harsh environment, with an avifauna dominated by seabirds, they are the only common and widespread land-based birds. As predators and scavengers they are strongly dependent for food on colonial seabirds, particularly penguins. They are stealing unguarded eggs and small chicks. They are not globally threatened with population numbers of about 10 000 pairs.
From album: Antarctic Biodiversity