Cepphus is a genus of seabirds in the auk family also referred to as true guillemots or, in North America, simply as guillemots. The genus name Cepphus is from Ancient Greek kepphos, a pale waterbird mentioned by Greek authors including Aristotle. The English word "guillemot" is from French guillemot probably derived from Guillaume, "William". "Murre" is of uncertain origins, but may imitate the call of the common guillemot.
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.
These birds may overwinter in their breeding areas, moving to open waters if necessary, but usually not migrating very far south.
The species are:
- Black guillemot or Tystie, Cepphus grylle
- Pigeon guillemot, Cepphus columba
- Spectacled guillemot, Cepphus carbo
There are also fossil forms
- Cepphus olsoni (San Luis Rey River Late Miocene - Early Pliocene of W USA)
- Cepphus cf. columba (Lawrence Canyon Early Pliocene of W USA)
- Cepphus cf. grylle (San Diego Late Pliocene, W USA)
The latter two resemble the extant species, but because of the considerable distance in time or space from their current occurrence may represent distinct species.
- Jobling, James A (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 96. ISBN 978-1-4081-2501-4.
- "Guillemot". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public library membership required.)
- "Murre". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public library membership required.)