Guillemots and Murres are medium to large sea birds in the auk family. There are two genera,
Uria and Cepphus and five species.

Common Guillemot or Common Murre, Uria aalge
Brünnich's Guillemot or Thick-billed Murre, Uria lomvia

Black Guillemot or Tystie, Cepphus grylle
Pigeon Guillemot, Cepphus columba
Spectacled Guillemot, Cepphus carbo

The birds in the Uria genus are called Murres in the United States and Guillemots in Britain, while the genus Cepphus are Guillemots in both the U.S. and Britain. Photos are presented for those species in red.