The pigeon guillemot (Cepphus columba) (<!--per the path of wikt:pigeon_guillemot leading to wikt:guillemot#English, and M-W Collegiate agrees with the pron given there-->) is a species of bird in the auk family, Alcidae. One of three species in the genus Cepphus, it is most closely related to the spectacled guillemot. There are five subspecies of the pigeon guillemot; all subspecies, when in , are dark brown with a black iridescent sheen and a distinctive wing patch broken by a brown-black wedge. Its has mottled grey and black and white . The long bill is black, as are the claws. The legs, feet, and inside of the mouth are red. It closely resembles the black guillemot, which is slightly smaller and lacks the dark wing wedge present in the pigeon guillemot.
This seabird is found on North Pacific coastal waters, from Siberia through Alaska to California. The pigeon guillemot breeds and sometimes roosts on rocky shores, cliffs, and islands close to shallow water. In the winter, some birds move slightly south in the northernmost part of their range in response to advancing ice and migrate slightly north in the southern part of their range, generally preferring more sheltered areas.
This species feeds on small fish and marine invertebrates, mostly near the sea floor, that it catches by pursuit diving. Pigeon guillemots are monogamous breeders, nesting in small colonies close to the shore. They defend small territories around a nesting cavity, in which they lay one or two eggs. Both parents incubate the eggs and feed the chicks. After leaving the nest the young bird is completely independent of its parents. Several birds and other animals prey on the eggs and chicks.
The pigeon guillemot is considered to be a least concern species by the International Union for Conservation of Nature due to its large, stable population and wide range. Threats to this bird include climate change, introduced mammalian predators, and oil spills.
Taxonomy and nomenclature
The pigeon guillemot is one of three species of auk in the genus Cepphus, the other two being the black guillemot of the Atlantic Ocean and the spectacled guillemot from the Eastern Pacific. It was described in 1811 by Peter Simon Pallas in the second volume of his Zoographia Rosso-Asiatica. A 1996 study looking at the mitochondrial DNA of the auk family found that the genus Cepphus is most closely related to the murrelets from the genus Synthliboramphus. Within the genus, the pigeon guillemot and spectacled guillemot are sister species, and the black guillemot is basal within the genus.