Cassin's Auklet
A species of Cassin'S Auklets Scientific name : Ptychoramphus aleuticus Genus : Cassin'S Auklets
Cassin's Auklet, A species of Cassin'S Auklets
Botanical name: Ptychoramphus aleuticus
Genus: Cassin'S Auklets
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Description People often ask General Info
Photo By silversea_starsong , used under CC-BY-NC-4.0 /Cropped and compressed from original
Description
Cassin's auklet (Ptychoramphus aleuticus) is a small, chunky seabird that ranges widely in the North Pacific. 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. It is divided into two subspecies: P. a. aleuticus – (Pallas, 1811): Aleutian Islands & south Alaska to northern Baja California.Kurile Islands. P. a. australis – (van Rossem, 1939): southern Baja California. 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.
Size
23 cm (9 in)
Life Expectancy
6-20 years
Nest Placement
Burrow
Feeding Habits
Cassin's Auklet primarily consume small fish, squid, and crustaceans, including Pacific whiting, herring, northern anchovy, rockfish, sculpin, and flatfish. They forage by diving, often less than 50 feet but capable of exceeding 100 feet, using their wings to 'fly' underwater. They also feed on fish eggs, crab larvae, larval squid, copepods, euphausiids, and amphipods.
Habitat
Cassin's Auklet predominantly inhabits the open ocean, thriving in regions where ocean currents like upwellings concentrate their prey. These birds are adapted to a life far from mainland, opting for sea islands from Alaska to Mexico for nesting. They show a preference for islands that offer rocky crevices or stable soil suitable for burrow excavation. While their nesting sites can vary from mountainous to flat terrain, and may include sparse forests, cassin's Auklet tends to avoid densely wooded or thorny areas.
Nest Behavior
Cassin's Auklet pairs select the nest site together. Nest building occurs in crevices or by burrowing with feet. Egg laying follows at the end of the burrow or crevice. They exhibit biparental care, with both parents involved in rearing the young.
Nest Characteristics
Cassin's Auklet typically nests in rocky crevices or soil burrows, sometimes under cacti in Mexico. Unlined burrows are about 3 feet deep and 5.5 inches in diameter, with a nest area of 6.7 inches wide by 4.7 inches tall. They also use shallow crevices or artificial nest boxes.
Dite type
Aquatic invertebrate eater
People often ask
General Info
Feeding Habits
Bird food type
Behavior
The cassin's Auklet showcases a variety of intriguing behaviors, particularly during its breeding seasons which vary regionally. At breeding sites, it engages in nocturnal courtship rituals to avoid predation, involving elaborate displays and vocalizations. Socially monogamous, they can exhibit polygyny with males occasionally courting additional females. The cassin's Auklet actively defends its burrow, resulting in territorial disputes that may escalate to physical altercations. Extraordinarily, some populations have dual nesting seasons, a unique trait among its family. Outside breeding times, cassin's Auklet forages at sea, either solo or in pairs, but may form large flocks in food-rich areas, communicating with twittering calls in foggy conditions.
Species Status
Cassin's auklet is listed as Near Threatened, 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. 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.
Photo By silversea_starsong , used under CC-BY-NC-4.0 /Cropped and compressed from original
Scientific Classification
Phylum
Chordates Class
Birds Order
Shorebirds Family
Alcidae Genus
Cassin'S Auklets Species
Cassin's Auklet