Cepphus is a genus of seabirds in the auk family also referred to as true guillemots or, in North America, simply as guillemots. These are medium-sized birds with mainly black plumage in the breeding season, thin dark bills and red legs and feet. Two species have white wing patches, the third has white facial “spectacles”. They are much paler in winter plumage, mottled above and white below.