The Guillemots comprise two genera of auks, Uria and Cepphus. Genera Alle Uria Alca Pinguinus Cepphus Brachyramphus Synthliboramphus Ptychoramphus Cyclorrhynchus Aethia Cerorhinca Fratercula Auks are birds of the family Alcidae in the order Charadriiformes. ...
The guillemots of Europe are murres in North America, if they occur in both continents, and the Little Auk becomes the Dovekie.
Some species, such as the Uria guillemots, nest in large colonies on cliff edges; others, like the Cepphus guillemots, breed in small groups on rocky coasts; and the puffins, auklets and some murrelets nest in burrows.
Time depth recorders on auks have shown that they can dive as deep as 100 m in the case of Uria guillemots, 40 m for the Cepphus guillemots and between 30 m for the auklets.