Cassin's auklet | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Charadriiformes |
Family: | Alcidae |
Genus: | Ptychoramphus Brandt, JF, 1837 |
Species: | P. aleuticus |
Binomial name | |
Ptychoramphus aleuticus (Pallas, 1811) | |
Cassin's auklet (Ptychoramphus aleuticus) 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.
Cassin's auklet is a small (25 cm, 200 g) nondescript auk. Its plumage is generally dark above and pale below, with a small white mark above the eye. Its bill is overall dark with a pale spot, and its feet are blue. Unlike many other auks, Cassin's auklet lacks dramatic breeding plumage, remaining the same over most of the year. At sea it is usually identified by its flight, which is described as looking like a flying tennis ball.
Cassin's auklet ranges from midway up the Baja California peninsula to Alaska's Aleutian Islands, off North America. It nests on offshore islands, with the main population stronghold being Triangle Island off Vancouver Island's Cape Scott, where the population is estimated to be around 55,0000 pairs. It is not known to be migratory. However, northern birds may move farther south during the winter.
Two subspecies are recognised: [2]
An extinct relative or predecessor species, Ptychoramphus tenuis L. H. Miller et Bowman, 1958, is known from the Late Pliocene of the San Diego Formation in California.
Cassin's auklet nests in burrows on small islands, and in the southern area of its range may be found in the breeding colony year round. It either digs holes in the soil or uses natural cracks and crevices to nest in, also readily using man-made structures. Pairs will show a strong loyalty towards each other and to a nesting site for many years. Both the parents incubate the single white egg, returning to swap shifts at night (usually after 2300 h) to avoid being taken by predators such as the western gull or peregrine falcon. They also depart from the colony before dawn. The egg is incubated for 40 days, the small chick is then fed nightly for 35 days by both parents, who regurgitate partially digested food (euphausiids and other small crustaceans) carried in a special gular pouch, often referred to in the literature as a sublingual pouch. The chick fledges alone and makes its way to the sea. Cassin's auklet is unusual amongst seabirds in occasionally laying a second clutch after a successful first clutch (it is the only northern hemisphere seabird to do so).
Most individuals in a cohort begin breeding at age 3 (27%), and by 8 years >95% of a given cohort has recruited. [3] Mean age of recruitment is 3.6 years. [3] Minimum annual breeding propensity is 0.83, apparent local survival is 0.76, juvenile survival (ages 0 to 2) is 0.15. [3]
At sea Cassin's auklets feeds offshore, in clear often pelagic water, often associating with bathymetric landmarks such as underwater canyons and upwellings. Numbers at sea may be grossly underestimated because the bird moves away from ships at a distance of more than a kilometer. Recently their distribution around Triangle Island has been determined by telemetry. It feeds by diving underwater beating its wings for propulsion, hunting down large zooplankton, especially krill. It can dive to 30 m below the surface, and by some estimates 80 m.
Cassin's auklet is listed as Near Threatened, [4] and some populations (principally the Farallon Islands population) have suffered steep declines. Threats to the auklet include introduced carnivores (particularly in Alaska), oil spills and changes in sea surface temperature (caused by El Niño events). Cassin's auklet is protected under the Migratory Bird Treaty Act of 1918. [5] Annual variation in ocean climate synchronously affects multiple demographic parameters including survival, breeding propensity, breeding success, and recruitment, a situation conducive to rapid population declines due to climate change. [6]
In the last few months of 2014, the carcasses of thousands of Cassin's auklets washed ashore from Northern California up to the north coast of Washington State. [7] The Coastal Observation and Seabird Survey Team estimated a toll between 50,000 and 100,000 deaths that year. Scientists were uncertain about the cause of these deaths. While viruses, bacteria, and oil spills were ruled out the cause appeared to be starvation. Scientists found little evidence of food in the stomachs of the carcasses. Some scientists from the California's Farallon Institute believe these mass deaths could be related to the unusual North Pacific warmth which is pushing marine food chains [8] [9] and could affect other species of zooplankton, krill and fish that normally develop in cold waters and the birds that consume them including Cassin's auklets. The event happened in the late summer when the auklet chicks began to fledge. [8]
The tufted puffin, also known as crested puffin, is a relatively abundant medium-sized pelagic seabird in the auk family (Alcidae) found throughout the North Pacific Ocean. It is one of three species of puffin that make up the genus Fratercula and is easily recognizable by its thick red bill and yellow tufts.
Puffins are any of three species of small alcids (auks) in the bird genus Fratercula. These are pelagic seabirds that feed primarily by diving in the water. They breed in large colonies on coastal cliffs or offshore islands, nesting in crevices among rocks or in burrows in the soil. Two species, the tufted puffin and horned puffin, are found in the North Pacific Ocean, while the Atlantic puffin is found in the North Atlantic Ocean.
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 common murre also called the common guillemot or foolish guillemot,(Uria aalge) is a large auk. It has a circumpolar distribution, occurring in low-Arctic and boreal waters in the North Atlantic and North Pacific. It spends most of its time at sea, only coming to land to breed on rocky cliff shores or islands.
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 western gull is a large white-headed gull that lives on the west coast of North America and the Pacific Ocean. The western gull ranges from British Columbia, Canada, to Baja California, Mexico.
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.
The rhinoceros auklet is a seabird and a close relative of the puffins. It is the only extant species of the genus Cerorhinca. Given its close relationship with the puffins, the common name rhinoceros puffin has been proposed for the species.
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 whiskered auklet is a small seabird of the auk family. It has a more restricted range than other members of its genus, Aethia, living only around the Aleutian Islands and on some islands off Siberia, and breeding on these islands. It is one of the smallest alcids, only the closely related least auklet being smaller. Its name is derived from the long white feathers on its face that are part of its breeding plumage.
The least auklet is a seabird and the smallest species of auk. It is the most abundant seabird in North America, and one of the most abundant in the world, with a population of around nine million birds. They breed on the islands of Alaska and Siberia, and spend the winter close to the edge of the ice sheet. Their largest colonies are on the Aleutian Islands, St. Lawrence Island and Little Diomede Island.
The crested auklet is a small seabird of the family Alcidae, distributed throughout the northern Pacific and the Bering Sea. The species feeds by diving in deep waters, eating krill and a variety of small marine animals. It nests in dense colonies of up to 1 million individuals in the Bering Sea and the Sea of Okhotsk. It often breeds in mixed-species colonies with the least auklet, a smaller congener.
The fork-tailed storm petrel is a small seabird of the storm petrel family Hydrobatidae. It is the second-most abundant and widespread storm petrel and is the only bird in its family that is bluish-grey in colour.
Craveri's murrelet is a small seabird which breeds on offshore islands in both the Pacific Ocean and the Gulf of California off the Baja peninsula of Mexico. It also wanders fairly regularly as far as central California in the US, primarily during post-breeding dispersal. It is threatened by predators introduced to its breeding colonies, by oil spills, and by tanker traffic. Increasing tourism development and commercial fishing fleets also further threaten the species. With an estimated population of 6,000-10,000 breeding pairs, its population is listed as vulnerable.
Aethia is a genus of four small (85–300g) auklets endemic to the North Pacific Ocean, Bering Sea and Sea of Okhotsk and among some of North America's most abundant seabirds. The relationships between the four true auklets remains unclear. Auklets are threatened by invasive species such as Norway rats because of their high degree of coloniality and crevice-nesting.
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.
Dow's puffin is an extinct seabird in the auk family described in 2000 from subfossil remains found in the Channel Islands of California. It was approximately as large as the modern horned puffin and its beak appeared to have been an intermediate between the rhinoceros auklet and the horned puffin. It lived during the Late Pleistocene and Early Pleistocene on the Channel Islands, where it nested alongside the ancient murrelet, Cassin's auklet and Chendytes lawi.