>Aethia pygmaea (Whiskered Auklet)

Whiskered Auklet

Whiskered Auklet
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Charadriiformes
Family:	Alcidae
Genus:	Aethia
Species:	A. pygmaea
Binomial name
Aethia pygmaea (Gmelin, 1789)

The Whiskered Auklet, Aethia pygmaea, 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 (like Commander Islands), 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 Whiskered Auklet is a poorly studied species and much research needs to be undertaken on the species. It was originally described as two different species, from specimens collected at different ends of its range, however research has shown that it is a single species with clinal variation along its range. It is not thought to undertake migration, but instead attends its breeding islands year round. Whiskered Auklets lay a single egg in a rocky crevice, in loose colonies with other Whiskered Auklets and also other colonial seabirds. Both parents take part in incubation and chick rearing. The whiskers have been shown to help them sense their way to and out of their nests at night.

Whiskered Auklets feed in the inshore zone, usually within 16 km of land, where tidal currents concentrate their prey into dense swarms. They feed predominantly on copepods during the summer months, mostly on the species Neocalanus plumchrus; and switching to euphausiid krill in the fall and winter.

>Aethia pusilla (Least Auklet)

Least Auklet

Least Auklet
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Charadriiformes
Family:	Alcidae
Genus:	Aethia
Species:	A. pusilla
Binomial name
Aethia pusilla (Pallas, 1811)

The Least Auklet, Aethia pusilla, 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.

Least Auklets feed predominantly on calanoid copepods, particularly those of the genus Neocalanus. They also eat euphausiids, pteropods and other zooplankton species. They hunt for these in stratified waters caused where upwelling and thermoclines cause these prey items to be tightly clumped together. Like all auks they are pursuit divers, using their wings to provide thrust and "fly" under the water. They are voracious predators, consuming 86% of their body weight each day.

Least Auklets are highly colonial, nesting in rocky crevices in colonies of up to a million birds. These colonies are often mixed, with other species of auklet nesting with, and competing with the Least Auklets. While this coexistence with other species may bring the benefits of protection from predators, Least Auklets are vulnerable to being displaced from their nesting sites by the larger Crested Auklets. A single egg is laid in the crevice and incubated for a month, after which a semi-precocial black downy chick is hatched. Both parents share incubation duties, as well as brooding and feeding duties. Unlike many auks, which are fed fish carried crosswise in the bill, chicks of the Least Auklet are fed copepods and other zooplankton from a sublingual pouch, as are other small auklets. The chicks receive no further parental care after they fledge, and can dive to hunt as soon as they leave the nest.

Least Auklets are vulnerable to oil spills and introduced species. The introduction of Arctic Foxes to many of the Aleutian Islands caused the species to be wiped out on many of those islands, and rats are also a problem on many islands. However, at present they are still a very common species.

>Aethia psittacula (Parakeet Auklet)

Parakeet Auklet

Parakeet Auklet
Aethia psittacula
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Charadriiformes
Family:	Alcidae
Genus:	Aethia
Species:	A. psittacula
Binomial name
Aethia psittacula (Pallas, 1769)
Synonyms
Cyclorrhynchus psittacula Phaleris psittacula

The Parakeet Auklet (Aethia psittacula) is a small seabird of the North Pacific. It used to be placed on its own in the genus Cyclorrhynchus (Kaup, 1829) but recent morphological and genetic evidence suggest it should be placed in the genus Aethia. It is associated with the boreal waters of Alaska and Kamchatka and Siberia. It breeds on the cliffs, slopes and boulder fields of offshore islands, generally moving south during the winter.

Description

The Parakeet Auklet is a small (23 cm) auk with a short orange bill that is upturned to give the bird its curious fixed expression. The bird's plumage is dark above and white below. with a single white plume projecting back from the eye. There is a small amount of variation between breeding and winter plumage.

The Parakeet Auklet is a highly vocal species at the nest, calling once it arrives at the nest and then duetting once its mate arrives. It makes a series of rhythimc hoarse calls (like that of the Cassin's Auklet) and a quavering squeal. The function of these are unknown, but could be associated with defending its burrow from intruders and strengthening the bond with its mate.

Behaviour and Breeding

The Parakeet Auklet is highly social in its breeding colonies.

The Parakeet Auklet's food varies with season, during the breeding season it takes mostly small planktonic crustaceans such as euphausiids,
copepods and amphipods. Recent research shows it also preys on jellyfish in some areas. It often feeds at a considerable distance from the colony, diving up to 30 m to reach its prey.

Breeding begins in April and May in colonies that are often shared with other auk species. The pair lay one egg, which is incubated for just over a month, the chick is then fed 4 times a day for around 35 days. The chick fledges at night, flying out to sea alone.

Status and Conservation

The Parakeet Auklet is not considered threatened, there are estimated to be over a million individuals in the North Pacific. It is not thought to have declined recently, but may be threatened in the future by introduced predators and oil spills.

>Aethia cristatella (Crested Auklet)

Crested Auklet

Crested Auklet
Conservation status
Least Concern (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Charadriiformes
Family:	Alcidae
Genus:	Aethia
Species:	A. cristatella
Binomial name
Aethia cristatella (Pallas, 1769)

The Crested Auklet (Aethia cristatella) is a small seabird of the family Alcidae which nests in huge colonies (>1 million individuals) in the Bering Sea and Sea of Okhotsk. They often breed in mixed-species colonies with Least Auklets, their smaller congener.

The Crested Auklet can measure 18–27 cm (7.1–11 in) in length, 34–50 cm (13–20 in) in wingspan and weigh 195–330 g (6.9–12 oz). It is recognized primarily by two characters in the breeding season. The first is its 'crest', a group of bristle feathers located above its eye on the top of its head. The second is a social odor that the auklets produce during the breeding season, which has been described as smelling like tangerines.

Crested Auklets are planktivores. Their diet consists mainly of krill, but they are also known to eat copepods, pteropods (such as Limacina), amphipods and larval fishes. Their main predators areHerring Gulls and other gulls, Arctic Fox and ravens, but they have been reported in the stomachs of halibut caught on St. Lawrence Island.

>>Genus Aethia

Aethia

Aethia
Aethia pygmaea
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Charadriiformes
Family:	Alcidae
Genus:	Aethia Merrem, 1788
Species
Aethia cristatella Aethia psittacula Aethia pusilla Aethia pygmaea

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 Arctic Foxes (Alopex lagopus) and Norway Rats (Rattus norvegicus) because of their high degree of coloniality and crevice-nesting.

Taxonomy and Evolution

Current accepted taxonomy of the Alcidae with Aethia shown in blue. Modified from Friesen et al. 1996. Mol. Biol. Evol. 13, 359-367.

The genus Aethia occurs only in the North Pacific and adjacent waters, mainly in the Bering Sea region. Along with Cassin's Auklet (Ptychoramphus aleuticus) they comprise the monophyletic tribe Aethinii. Molecular work has not yet resolved the relationship between the Aethiaauklets, but the group is a sister group to Cassin's Auklet, which is, in turn, a sister group to the Fraterculine auks (puffins and Rhinoceros Auklet).

The genus Aethia did not enter into widespread use until the 1960s.Initially, the auklets were placed in Alca, but later reorganized into genera including: Simorhynchus,Phaleris and Cyclorhynchus. Cyclorhynchus is still occasionally used for the Parakeet Auklet.

Fossil record

The first undisputed auk fossils are from the middle Miocene (15 million years ago).The first Aethia fossils date from the late Miocene (10-15 million years ago)  and the four species likely diverged rapidly about 5 million years ago.

There are one or two fossil species which lived in the area of today's California during the Late Miocene, some 5 million years ago: Aethia rossmoori (Monterrey Formation of Orange County) and an undescribed taxon tentatively placed in this genus.

Species

There are four species of Aethia.

• 

  Least Auklet Aethia pusilla
 
• 

  Crested Auklet Aethia cristatella
 
• 

  Whiskered Auklet Aethia pygmaea
 
• 

  Parakeet Auklet Aethia psittacula

Distribution

Population Estimates

Censusing breeding auklets can be difficult because they nest in hidden crevices. At present, population estimates are:

• Least Auklet - 20,000,000+
• Whiskered Auklet - 100,000 - 250,000
• Crested Auklet - 5,000,000 - 10,000,000
• Parakeet Auklet - 1,000,000 - 2,000,000

Breeding Season

Aethia auklets are endemic to the North Pacific Ocean and Sea of Okhostk with notable Asian colonies in the Kuril Islands, Commander Islands, along the Kamchatka and Chukota Peninsulas. In North America, large colonies are in the Aleutian Islands (Buldir, Kiska,Semisopochnoi and Gareloi) to the Gulf of Alaska and north to the islands of the Bering Sea (St. Lawrence Island, Pribilof Islands, St. Matthew Island).

Auklets are have high site fidelity, at both the colony and crevice level, although there can be a high divorce rate of up to 33% in Least and Crested Auklets when both mates survive.

Winter Distribution

Winter distribution of auklets is poorly known. Whiskered Auklets likely winter near to breeding colonies and many were reported by Aleuts to winter in the general area. Auklets from the northern Bering Sea must move further south because of pack ice surrounding colonies during the winter.

Breeding

Auklets are typically very social and nest in dense colonies (Parakeet Auklets are more dispersed). All have some form of facial ornamentation such as large crests (Whiskered and Crested Auklets), auricular plumes (all four species), and Crested and Whiskered Aukletshave a tangerine-scented odour which may function in mate choice or species recognition, although this requires more study.

All Aethia auklets lay one white egg in a natural crevice and incubate for 25–36 days, after which, a semi-precocial chick emerges and fledges after 25–35 days. Age at first breeding is estimated at 3–5 years. Colony sizes are highly variable, and range from less than 100 individuals to over 1 million, although Least and Crested Auklets tend to nest in greater density than Parakeet and Whiskered Auklets.

Diet

The auklets are mainly planktivores, eating a variety of calanoid copepods, euphausiids and other invertebrates such as jellyfish andctenophores. Winter diet has not been studied.

Threats and Conservation

Because they nest in crevices, auklets are vulnerable to predation by rats, and have been extirpated from some islands that contained Arctic Foxes introduced for farming. Eradication of rats from Rat Island was completed in 2008 and 2009.

The large colony at Sirius Point, Kiska Island, Alaska (perhaps the largest auklet colony in the world) experienced almost complete breeding failure in 2001 and 2002 because of rat predation and disturbance and has been the focus of researchers at Memorial University of Newfoundland.