Auk

Auk, marine diving bird of the family Alcidae, including razorbills, puffins, and guillemots. Of the 22 species (including the extinct great auk) the smallest is the dovekie, or little auk (Plautus alle), which is about the size of a robin (lengths of other species are 6–30 in/15–76 cm). Auks, who seldom leave the water except to nest, usually breed in colonies, sometimes millions of individuals, and nest on high ledges or in burrows.

See also: Guillemot; Murre; Puffin.