0 the pigeon guillemot (cepphus columba) is a species of bird in the auk family , alcidae .
1  it is endemic to the pacific ocean .
2  it closely resembles the other members of the genus cepphus , particularly the black guillemot , which is slightly smaller and lacks dark wing lines .
3 adult birds have black bodies with a white wing patch broken by a black wedge , a thin dark bill and red legs and feet .
4  in winter , the upper parts are mottled grey and black and the underparts are white .
5  they walk well and habitually have an upright posture .
6 their breeding habitat is rocky shores , cliffs and islands , often forming small loose colonies .
7  they usually lay their eggs in rocky cavities near water , but will often nest in any available cavity including caves , disused burrows of other seabirds and even old bomb casings .
8  unlike many alcids , pigeon guillemots are diurnal and lay two eggs .
9  because they can feed their chicks constantly throughout the day , the chicks fledge faster than equivalent sized auks that are only provisioned at night .
10 pigeon guillemots range across the northern pacific from the kuril islands and the kamchatka peninsula in siberia to coasts in western north america from alaska to california .
11  after the breeding season birds in alaska migrate south to open waters , whereas some birds from california move north to the waters off british columbia .
12  birds usually return to their natal colony to breed .
13 they dive for food from the surface , swimming underwater , feeding on benthic prey , which is usually obtained close to shore .
14  they mainly eat fish and other aquatic animals , particularly sculpins , sandfish (trichodon), cods , capelin , and crabs .
15  chick diet varies slightly , with more fish than invertebrates , particularly rockfish .
