Cepphus columba is a species of small seabirds commonly found in cold waters of the northern hemisphere. This bird is known by a number of different synonyms, including the pigeon guillemot, the Pacific guillemot, the Pigeon Auk, and the Garefowl. These names all refer to the same bird, which is typically around 30cm long and has a distinctive, black-and-white plumage. The pigeon guillemot is a valuable indicator species in many marine ecosystems, in part because it feeds exclusively on fish that are found in cold ocean waters. Despite being widely distributed and relatively abundant, the species faces a number of threats, including habitat loss, overfishing, and pollution.