Chionidae – Sheathbills

These pigeon-like birds are unique in being the only family of birds that are indigenous to the Antarctic and sub-Antarctic regions as breeders.

Sheathbills are distinctive for their entirely white plumage, which provides excellent camouflage against the snow and ice of their native habitats. They have short, strong legs adapted to their mostly terrestrial lifestyle, and unlike most other birds in the Antarctic region, sheathbills do not have webbed feet. This trait reflects their adaptation to life on land rather than in the sea.

The bill of the sheathbill is robust and covered by a horny sheath, which is either black or a combination of yellow and black, depending on the species. The cheeks of these birds are naked and feature wattles, which are more prominent in males and may play a role in mating displays or other social interactions. Another notable feature is the sharp carpal spike protruding from their wings, which can be used defensively.

Sheathbills are gregarious birds, often found in groups, and are known for their omnivorous diet. They feed on a wide range of items, from invertebrates and small fish to carrion and human refuse. Their opportunistic feeding habits allow them to survive in the harsh conditions of their environment.

These birds are also known for their nesting behavior. Sheathbills typically breed on subantarctic islands and the Antarctic Peninsula. During the breeding season, they make nests in a variety of locations, including rock crevices, and even in the burrows, they dig themselves. The flexibility of their nesting sites adapts to the limited availability of suitable nesting areas in their barren landscapes.

In the southern winter, sheathbills migrate north to the Falkland Islands and coastal regions of southern South America. This migration allows them to exploit different ecological niches and food sources throughout the year.