AUKS, RAZORBILLS, GUILLEMOTS, and PUFFINS.
Bill high and sharp on culmen. No hind toe. Anterior toes fully webbed. Third toe longest. Tail twelve to eighteen feathers. Schizognathous. Differ from Gulls in their squat Appearance, extraordinary diving powers, close-set plumage, manner of nidification, and shape of egg. Two moults in a year. Breed in Arctic and sub-Arctic regions, never found south of equator. No nest, one egg (the Black Guillemot excepted).