Кайра обыкновенная: описание и распространение.

Seabird in the auk family from North Pacific coastal waters

The pigeon guillemot (Cepphus columba) ('/ɡ//ɪ//l//ɪ//m//ɒ//t/) 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.

The pigeon guillemot is a medium sized auk, in length and weighing Both sexes are alike in appearance and mass, except for Californian birds where females were found to have larger bills than males. The summer or of the adult is mostly dark brown with a black sheen, with a white wing patch broken by a brown black wedge. In winter, the are iridescent black, often with black fringes giving a scalloped appearance, and the and rump are white. The forehead, , , eye line and ear coverts are black with white tips, sometimes the tips are narrow and the head looks black. Adults moult into their winter or between August and October, taking around a month to complete and leaving the bird unable to fly for around four weeks. Birds moult into their breeding plumage between January and March. The legs and feet are red, with black claws. The iris is brown and the eye is surrounded by a thin unbroken white eye ring. The bill is long and black and the inside of the mouth is red. The pigeon guillemot walks well and habitually has an upright posture. When sitting it frequently rests on its tarsi. 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. It generally is philopatric, meaning it returns to the colony where it hatched to breed, but it sometimes moves long distances after fledging before settling, for example a chick ringed in the Farallones was recorded breeding in British Columbia. It is noted that pigeon guillemots do not inhabit nests with gull eggs, specifically those of the western gull. This guillemot usually retains its nest site, meaning that nest sites are generally used multiple times, although it does not display this behaviour if its mate does not return to breed. Colonies are attended during the day and, except for birds incubating or brooding, adults do not remain in the colony at night. Birds usually arrive in the colony in the morning, with counts decreasing after early afternoon, when high tide is. Colony attendance is affected by the tide, more appearing when the tide is higher and less when the tide is lower, probably because the prey this bird feeds on is more accessible during low tide, thus more birds are away from the colony. The counts vary the most before laying, while they are relatively stable during incubation and egg laying. Pigeon guillemots form long term pair bonds, the pairs usually reuniting each year, although occasionally pairs divorce. although the time taken to fledge has been known to take anywhere from 29 to 54 days. The function of this call is to advertise ownership of a territory. Another call, the trill, denotes ownership over larger distances. Trills can be performed singly or as duets between pairs; if performed as a duet then the call also functions to help reinforce pair bond. Trills are usually given from a resting position, except for the trill waggle, which has the bird raising its tail, opening its wings and ruffling the feathers of its neck and head, followed by a waggling of its outstretched neck and head. and during the breeding season within of the colony. Dives of two to ten seconds are typical when feeding on shoals of sandlance at the water's surface. The chick's diet varies slightly, with more fish than invertebrates, particularly rockfish (family Sebastidae).

Avian predation is the most common cause of egg loss in the pigeon guillemot. Species that prey on the nests include the northwestern crow, a common predator of both eggs and chicks, as well as glaucous winged gulls, stoats and garter snakes. In the water, they have been reported to be taken by orca and giant Pacific octopuses. It is also vulnerable to the cestode Alcataenia campylacantha. Ticks (Ixodes uriae) and fleas (Ceratophyllus) have been recorded on chicks as well. Climate change has a negative effect on this bird, and reproductive performance decreases with increased temperatures. It is also particularly vulnerable to oil, and adults near oiled shores display symptoms of hepatocellular injury, where elevated levels of aspartate aminotransferase can be found in the liver. Otherwise, the effects of oil spills on the pigeon guillemot are unclear.