An auk or alcid is a bird of the family Alcidae in the order Charadriiformes. The alcid family includes the murres, guillemots, auklets, puffins, and murrelets. The family contains 25 extant or recently extinct species that are divided into 11 genera.
Seabirds are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene.
The pigeon guillemot 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 breeding plumage, are dark brown with a black iridescent sheen and a distinctive wing patch broken by a brown-black wedge. Its non-breeding plumage has mottled grey and black upperparts and white underparts. 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.
The razorbill, razor-billed auk, or lesser auk is a North Atlantic colonial seabird and the only extant member of the genus Alca of the family Alcidae, the auks. It is the closest living relative of the extinct great auk.
The ancient murrelet is a bird in the auk family. The English term "murrelet" is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot. Ancient murrelets are called "ancient" because they have grey on the back like a shawl, as worn by the elderly.
The black-capped petrel, also known as the diablotín, is a small seabird native to the West Indies in the genus Pterodroma. It is a long-winged petrel with a grey-brown back and wings, with a white nape and rump. Underparts are mainly white apart from a black cap and some dark underwing markings. It picks food items such as squid from the ocean surface.
The ashy storm petrel is a small, scarce seabird of the storm petrel family Hydrobatidae. It breeds colonially on islands off the coasts of California and Mexico, and is one of six species of storm petrel that live and feed in the rich California Current system.
The marbled murrelet is a small seabird from the North Pacific. It is a member of the family Alcidae, which includes auklets, guillemots, murres and puffins. It nests in old-growth forests or on the ground at higher latitudes where trees cannot grow. The marbled murrelet has declined in number since humans began logging its nest trees in the latter half of the 19th century. The decline of the marbled murrelet and its association with old-growth forests, at least in the southern part of its range, have made it a flagship species in the forest preservation movement.
The parakeet auklet is a small seabird of the North Pacific. Parakeet Auklets used to be placed on its own in the genus Cyclorrhynchus but recent morphological and genetic evidence suggest it should be placed in the genus Aethia, making them closely related to crested auklets and least auklets. It is associated with the boreal waters of Alaska, Kamchatka and Siberia. It breeds on the cliffs, slopes and boulder fields of offshore islands, generally moving south during the winter.
Cassin's auklet is a small, chunky seabird that ranges widely in the North Pacific. It is the only species placed in the genus Ptychoramphus. It nests in small burrows and because of its presence on well studied islands in British Columbia and off California it is one of the better known auks. It is named for the American ornithologist John Cassin.
The long-billed murrelet is a small seabird from the North Pacific. The genus name Brachyramphus is from Ancient Greek brakhus, "short", and rhamphos, "bill". The species name perdix is Latin for "partridge" Pallas described this auk as Magnitudine Perdicis. "Murrelet" is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot.
The Guadalupe murrelet or Xantus's murrelet is a small seabird found in the California Current system in the Pacific Ocean. This auk breeds on islands off California and Mexico. It is threatened by predators introduced to its breeding colonies and by oil spills.
Kittlitz's murrelet is a small alcid found in the waters off Alaska and Eastern Siberia. This near threatened species is, like the closely related marbled murrelet, unusual for seabirds in not being colonial, nesting instead in isolated locations on mountain tops, where the nests were known to Native Americans for many years before skeptical ornithologists described and photographed them. It is a poorly known and little studied species, although concern over its status and that of the closely related marbled murrelet has led to a recent increase in research.
The Japanese murrelet or crested murrelet is a small seabird in the auk family that occurs along the remote rocky coasts and in the offshore waters of Japan, and may also be found after the breeding season as far as Sakhalin to the north and in particular off South Korea. With a small and declining population, estimated as of 2017 to total 2,500–10,000 individuals, it is the rarest alcid, and the most at risk of extinction.
Brachyramphus is a small genus of seabirds from the North Pacific. Brachyramphus is from Ancient Greek brakhus, "short", and rhamphos, "bill". In English the species are named as "murrelets"; this is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot.
Synthliboramphus is a small genus of seabirds in the auk family from the North Pacific. The genus name Synthliboramphus is from Ancient Greek sunthlibo, "to compress", and rhamphos, "bill". The English name "Murrelet" is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot.
A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony. Colonial nesting birds include seabirds such as auks and albatrosses; wetland species such as herons; and a few passerines such as weaverbirds, certain blackbirds, and some swallows. A group of birds congregating for rest is called a communal roost. Evidence of colonial nesting has been found in non-neornithine birds (Enantiornithes), in sediments from the Late Cretaceous (Maastrichtian) of Romania.
Austral storm petrels, or southern storm petrels, are seabirds in the family Oceanitidae, part of the order Procellariiformes. These smallest of seabirds feed on planktonic crustaceans and small fish picked from the surface, typically while hovering. Their flight is fluttering and sometimes bat-like.
Seabirds include some of the most threatened taxa anywhere in the world. For example, of extant albatross species, 82% are listed as threatened, endangered, or critically endangered by the International Union for Conservation of Nature. The two leading threats to seabirds are accidental bycatch by commercial fishing operations and introduced mammals on their breeding islands. Mammals are typically brought to remote islands by humans either accidentally as stowaways on ships, or deliberately for hunting, ranching, or biological control of previously introduced species. Introduced mammals have a multitude of negative effects on seabirds including direct and indirect effects. Direct effects include predation and disruption of breeding activities, and indirect effects include habitat transformation due to overgrazing and major shifts in nutrient cycling due to a halting of nutrient subsidies from seabird excrement. There are other invasive species on islands that wreak havoc on native bird populations, but mammals are by far the most commonly introduced species to islands and the most detrimental to breeding seabirds. Despite efforts to remove introduced mammals from these remote islands, invasive mammals are still present on roughly 80% of islands worldwide.
Scripps's murrelet is a small seabird found in the California Current system in the Pacific Ocean. This auk breeds on islands off California and Mexico. It is threatened by predators introduced to its breeding colonies and by oil spills.
