The pigeon guillemot (Cepphus columba), a medium-sized auk endemic to the North Pacific, is strikingly patterned in the breeding season, when the red-orange legs and mouth lining are important signals in courtship. Generally found very close to rocky shores and on small islands that provide protection from predators, it breeds along both coasts of the North Pacific, south to Japan and southern California. The pigeon guillemot is similar to the related black guillemot, but can be distinguished by its larger size, and in the breeding season by its dusky-grey underwing and the dark brown wedge on the white wing patch.
