alcids

Alcids, or alcids, are a family of diving seabirds in the order Charadriiformes, commonly known as auks. They include puffins, murres (also called auklets in some groups), guillemots, and related species. The family contains several genera, such as Alca, Uria, Fratercula, Cepphus, Cerorhinca, Brachyramphus, Aethia, and others, with roughly two dozen species in total.

Physical characteristics of alcids are adapted for life at sea. They typically have compact, robust bodies, short wings, and strong bills. Their legs and feet are placed far back on the body, making them awkward on land but excellent divers and fast swimmers underwater, where they use wing beats and foot propulsion to chase prey. Plumage is usually black and white, though many species also show distinctive markings or colorful bills during the breeding season.

Distribution and habitat vary by species, but alcids commonly inhabit cold and temperate coastal waters of the northern hemisphere, from the Arctic to northern temperate seas. They nest on rocky cliffs, offshore islands, and, in the case of some forms like the marbled murrelet, in old-growth forests. They are highly colonial breeders, laying typically one egg per clutch, with both parents often sharing incubation and chick-rearing duties.

Diet consists mainly of small fish and crustaceans, captured by underwater pursuit. Alcids can be highly migratory, with populations ranging offshore during winter or moving between breeding and wintering grounds.

Conservation status varies; some species are abundant, while others are threatened or endangered due to habitat loss, introduced predators on breeding sites, and declines in prey from overfishing or environmental change. The great auk, once placed in this family, became extinct in the mid-1800s due to human exploitation.