Least auklets communicate through vocalizations. They are very vocal when in breeding colonies. Adults have four kinds of vocalization: chatter, deep chatter, chirp, and chirr-buzz. They slowly rock their heads when alternating notes.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Although least auklet populations are declining due to predation and pollution such as oil spills, least auklets have a large range and population size so their current IUCN conservation status is Least Concern.
US Migratory Bird Act: no special status
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse effects of least auklets on humans.
Least auklets are sometimes used as food by indigenous populations.
Positive Impacts: food
There is little information on the ecosystem roles that least auklets play.
Least auklets are invertivores. Adults dive into the water to find small crustaceans such as copepods and decapod larvae to feed upon. Young are fed by adults and mostly eat copepods so, during chick rearing, adults feed almost exclusively on copepods but may also eat krill.
Animal Foods: aquatic crustaceans
Primary Diet: carnivore (Eats non-insect arthropods)
Least auklets (Aethia pusilla) are found in the northern Pacific. Populations are native to the United States, Russia, and Japan. Occasional vagrants are seen in Canada.
Biogeographic Regions: nearctic (Native ); palearctic (Native ); pacific ocean (Native )
The marine habitat of least auklets consists of near shore waters to deep, pelagic waters. Terrestrial habitat is occupied during the breeding season and consists of rocky coasts, talus slopes, and cliffs.
Habitat Regions: temperate ; polar ; saltwater or marine
Aquatic Biomes: pelagic ; coastal
The average lifespan of least auklets is around 4.5 years.
Average lifespan
Status: wild: 4.5 years.
Least auklets are the smallest of the auklets, weighing about 86 g and measuring about 16 cm in length. Basic plumage consists of black to brown on the back and a white, spotted, or black breast. Variation in chest color signals status. They have yellow eyes and black webbed feet. Males and females have colorful bills, horny knob ornaments, and white facial plumes during the mating season.
Average mass: 86 g.
Average length: 16 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
Arctic foxes (Vulpes lagopus) and Norwegian rats (Rattus norvegicus, a non-native species) are major predators to least auklets. Humans are also known predators. They hunt least auklets for food and occasionally least auklets are caught in fishing nets.
Known Predators:
Least auklets are monogamous colonial breeders. Colony size may reach as many as 100,000 breeding pairs or more. Nests are found on rocky coasts, offshore islands, coastal scree, and cracks in coastal cliffs. Nests are hidden under rocks and are often reused in following years.
Mating System: monogamous
Least auklets lay only one egg at a time. Eggs are laid from June to August and take about 28 to 36 days for incubation. Young take about 26 to 31 days to fledge. It takes 3 or more years before least auklets breed for the first time.
Breeding interval: Least auklets breed once a year.
Breeding season: Least auklets breed from June to August.
Average eggs per season: 1.
Range time to hatching: 28 to 36 days.
Range fledging age: 26 to 31 days.
Range time to independence: 26 to 31 days.
Average age at sexual or reproductive maturity (female): 3 years.
Average age at sexual or reproductive maturity (male): 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Both parents take turns incubating the egg. After hatching, both continue to tend to the young. After fledging, there is no further parental care.
Parental Investment: altricial ; male parental care ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female)
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, and are not considered threatened by the IUCN.
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.
