Aethia pusilla - (Pallas, 1811)
Least Auklet
Taxonomic Status: Accepted
Related ITIS Name(s): Aethia pusilla (Pallas, 1811) (TSN 177020)
French Common Names: Starique minuscule
Unique Identifier: ELEMENT_GLOBAL.2.105309
Element Code: ABNNN10010
Informal Taxonomy: Animals, Vertebrates - Birds - Other Birds
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Aves Charadriiformes Alcidae Aethia
Genus Size: B - Very small genus (2-5 species)
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Concept Reference
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Concept Reference: American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Concept Reference Code: B98AOU01NAUS
Name Used in Concept Reference: Aethia pusilla
Conservation Status
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NatureServe Status

Global Status: G5
Global Status Last Reviewed: 23Apr2003
Global Status Last Changed: 27Nov1996
Rounded Global Status: G5 - Secure
Reasons: Very abundant; about 9 million breed on remote Aleutian Islands, islands in the Bering Sea, in the northwestern Pacific, and islands in the Sea of Okhotsk; some colonies threatened by introduced foxes and rats.
Nation: United States
National Status: N5 (19Mar1997)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alaska (S5)

Other Statuses

IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent: 200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)
Range Extent Comments: BREEDING: western Alaska from Diomede Islands south through islands of Bering Sea (including Pribilofs) to Aleutian, Shumagin, and Semidi Islands; also eastern Siberia, Commander Islands, central Kurile Islands, and islands in the Sea of Okhotsk (Jones 1993). NON-BREEDING: Present near breeding areas, north to the limit of open water in Bering and Okhotsk seas; some southward movement in the North Pacific (Jones 1993).

Number of Occurrences: 21 - 80
Number of Occurrences Comments: At least 22 sites mapped in the Bering Sea/Aleutian Islands area in Jones (1993). Other breeding colonies present on the Kamchatka Peninsula, Commander Islands, Kurile Islands, and on islands in the Sea of Okhotsk (summarized in Jones 1993).

Population Size: >1,000,000 individuals
Population Size Comments: One of the most abundant seabirds in North America. Total population estimated at 9 million (Jones 1993); Alaska population estimated at 6 million birds (Lensink 1984).

Number of Occurrences with Good Viability/Integrity: Few to some (4-40)
Viability/Integrity Comments: At least 6 colonies contain more than 300,000 individuals (Jones 1993).

Overall Threat Impact Comments: Arctic fox is major predator on some colonies but not on others (Roby and Brink 1986). In various areas, gulls (herring, glaucous-winged), voles, peregrine falcon, and humans have been noted as significant predators (Johnsgard 1987, Jones 1992). Norway rats are a major threat (predator) on the world's largest least auklet colony on Kiska Island (Aleutian Islands, Alaska).

Short-term Trend Comments: Alaska population presumably stable (Lensink 1984).

Other NatureServe Conservation Status Information

Distribution
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Global Range: (200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)) BREEDING: western Alaska from Diomede Islands south through islands of Bering Sea (including Pribilofs) to Aleutian, Shumagin, and Semidi Islands; also eastern Siberia, Commander Islands, central Kurile Islands, and islands in the Sea of Okhotsk (Jones 1993). NON-BREEDING: Present near breeding areas, north to the limit of open water in Bering and Okhotsk seas; some southward movement in the North Pacific (Jones 1993).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
NOTE: The maps for birds represent the breeding status by state and province. In some jurisdictions, the subnational statuses for common species have not been assessed and the status is shown as not-assessed (SNR). In some jurisdictions, the subnational status refers to the status as a non-breeder; these errors will be corrected in future versions of these maps. A species is not shown in a jurisdiction if it is not known to breed in the jurisdiction or if it occurs only accidentally or casually in the jurisdiction. Thus, the species may occur in a jurisdiction as a seasonal non-breeding resident or as a migratory transient but this will not be indicated on these maps. See other maps on this web site that depict the Western Hemisphere ranges of these species at all seasons of the year.
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AK

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted. For information on how to obtain shapefiles of species ranges see our Species Mapping pages at www.natureserve.org/conservation-tools/data-maps-tools.

Range Map Compilers: NatureServe, 2002

Ecology & Life History
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Basic Description: A bird (alcid, auklet).
Reproduction Comments: Eggs laid mostly in late May and June. Clutch size 1. Incubation 28-36 days, by both parents in turn. Young tended by both sexes, fully grown and fledged in 26-31 days, by end of August. First breeds at 3 or more years. Monogamous. Colonies may include more than 100,000 breeding pairs.
Ecology Comments: On St. Paul Island, annual adult survival was about 75%, relatively low for an alcid (Jones 1992).
Non-Migrant: Y
Locally Migrant: Y
Long Distance Migrant: N
Mobility and Migration Comments: Apparently fairly sedentary; migrating only as far as necessary to find open water for foraging. Appears near St. Lawrence Island breeding area in mid-May, around Pribilofs by mid- to late April (Johnsgard 1987).
Marine Habitat(s): Near shore, Pelagic
Terrestrial Habitat(s): Bare rock/talus/scree, Cliff
Habitat Comments: BREEDING: Nests on rocky coasts and offshore islands, on talus slopes and beach rock rubble, occasionally in small crevices in coastal cliffs (AOU 1983, Harrison 1978). Often uses same nest site in successive years (Roby and Brink 1986). NON-BREEDING: mostly pelagic, and at upwellings along rocky seacoasts and islands (AOU 1983).
Adult Food Habits: Invertivore
Immature Food Habits: Invertivore
Food Comments: Dives from surface of water to catch and eat small crustaceans (Terres 1980) (e.g., copepods, decapod larvae). Adults feed chicks mostly NEOCALANUS copepods (Alaska, Roby and Brink 1986). During chick rearing, monophagous on N. PLUMCHRUS (Alaska, Day and Byrd 1989). Adults also may eat euphausiids.
Adult Phenology: Circadian
Immature Phenology: Circadian
Phenology Comments: Adults may frequently spend night together in nest during incubation and chick rearing period. Activity at breeding colony ceases at nightfall (Roby and Brink 1986). Colony activity peaks in morning-early afternoon and just before dark.
Colonial Breeder: Y
Length: 16 centimeters
Weight: 86 grams
Economic Attributes Not yet assessed
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Management Summary
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Monitoring Requirements: See Piatt et al. (1990) and Jones (1992) for population monitoring recommendations.
Population/Occurrence Delineation
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Group Name: Colonial Seabirds

Use Class: Breeding
Subtype(s): Foraging Area, Breeding Colony
Minimum Criteria for an Occurrence: Evidence of historical breeding , or current and likely recurring breeding, at a given location, minimally a reliable observation of one or more breeding pairs in appropriate habitat. Be cautious about creating EOs for observations that may represent single breeding events outside the normal breeding distribution.
Mapping Guidance: Map foraging areas as separate polygons if they are separated from the breeding colony by areas simply flown over on commuting routes.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Alternate Separation Procedure: Where colonies are closer than 5 kilometers, separate occurrences may be created if research shows little genetic mixing between colonies.
Separation Justification: Occurrences include nesting and foraging areas, but occurrence separations are based on nesting areas (i.e., distance between nesting areas, regardless of foraging locations). Hence, different occurrences may overlap.

Occurrences are not based on discrete populations or metapopulations. Instead, the separation distance is arbitrarily small such that occurrences are of of practical size for data management purposes.

Evidence from a number of species of seabirds indicates that even though the 'home ranges' of individual nesting seabirds may be immense when foraging trips are taken into account, little movement or feeding overlap may occur between nearby colonies. For example, Thick-billed Murres may commute up to 170 kilometers one way on a feeding trip from the colony, but birds from a colony only 8 kilometers away may forage in a completely different direction; even birds from different sub-colonies only 1.5 kilometers apart mostly fed in completely separate areas (Gaston and Hipfner 2000).

Most seabirds have strong breeding site fidelity; e.g., Thick-billed Murres (Gaston and Hipfner 2000, Gaston et al. 1994), Gray-backed Tern (Mostello et al. 2000), Red-footed Booby (Schreiber et al. 1996).

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): 2 km
Inferred Minimum Extent Justification: Somewhat arbitrary, but generally very conservative for this group, many members of which travel long distances to foraging grounds.
Date: 20Oct2004
Author: Cannings, S., and G. Hammerson

Use Class: Nonbreeding
Subtype(s): Feeding area, Loafing site, Roosting site
Minimum Criteria for an Occurrence: Evidence of recurring presence of flocks of nonbreeding birds (including historical), including nonbreeding birds within the breeding season and breeding individuals outside the breeding season; and potential recurring presence at a given location. Normally only areas where concentrations greater than 25 birds regularly occur for more than 20 days per year would be deemed EOs; the number of individuals may be reduced for very rare species. Be cautious about creating EOs for observations that may represent single events.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 10 km
Separation Distance for Suitable Habitat: 10 km
Separation Justification: Separation distance arbitrary; defined this small to aid in conservation planning. Sites more than 10 kilometers apart may be joined as one occurrence if research shows that predominantly the same individuals are using both sites.
Date: 07Mar2001
Author: Cannings, S.
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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Element Ecology & Life History Edition Date: 25Jan1994
Element Ecology & Life History Author(s): HAMMERSON, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.

  • American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.

  • Byrd, G. V., R. H. Day, and E. P. Knudtson. 1983. Patternsof colony attendance and censusing of auklets at Buldir Island, Alaska. Condor 85:274-280.

  • Day, R. H., and G. V. Byrd. 1989. Fod habits of the whiskered auklet at Buldir Island, Alaska. Condor 91:65-72.

  • Gaston, A. J., and J. M. Hipfner. 2000. Thick-billed Murre (Uria lomvia). No. 497 IN A. Poole and F. Gill, editors, The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 32pp.

  • Gaston, A. J., et al. 1994. Population parameters of thick-billed murres at Coats Island, Northwest Territories, Canada. Condor 96:935-948.

  • Golovkin, A. N. 1984. Seabirds nesting in the USSR: the status and protection of populations. Pages 473-486 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.

  • Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.

  • Johnsgard, P. A. 1987. Diving birds of North America. Univ. Nebraska Press, Lincoln. xii + 292 pp.

  • Jones, I. L. 1992a. Colony attendance of least auklets at St. Paul Island, Alaska: implications for population monitoring. Condor 94:93-100.

  • Jones, I. L. 1992b. Factors affecting survival of adult least auklets (Aethia pusilla) at St. Paul Island, Alaska. Auk 109:576-584.

  • Jones, I. L. 1993. Least Auklet (Aethia pusilla). In A. Poole and F. Gill, editors, The Birds of North America, No. 69. Academy of Natural Sciences, Philadelphia, and American Ornithologists' Union, Washington, DC. 16 pp.

  • Lensink, C. J. 1984. The status and conservation of seabirds in Alaska. Pages 13-27 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Publ. No. 2.

  • Mostello, C. S., N. A. Palaia, and R. B. Clapp. 2000. Gray-backed Tern (Sterna lunata). No. 525 in A. Poole and F. Gill (editors). The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 28 pp.

  • Piatt, J. F., B. D. Roberts, and S. A. Hatch. 1990. Colony attendance and population monitoring of least and crested auklets on St. Lawrence Island, Alaska. Condor 92:97-106.

  • Poole, A. F. and F. B. Gill. 1992. The birds of North America. The American Ornithologists' Union, Washington, D.C. and The Academy of Natural Sciences, Philadelphia, PA.

  • Roby, D. D., and K. L. Brink. 1986. Breeding biology of least auklets on the Pribilof Islands, Alaska. Condor 88: 336-346.

  • Schreiber, E. A., R. W. Schreiber, and G. A. Schenk. 1996. Red-footed Booby (Sula sula). No. 241 in A. Poole and F. Gill, editors. The birds of North America. The Academy of Natural Sciences, Philadelphia, PA, and The Amerian Ornithologists' Union, Washington, DC. 24 pp.

  • Sealy, S. G., editor. 1990. Auks at sea. Western Foundation of Vertebrate Zoology, Studies in Avian Biology No. 14. vi + 180 pp.

  • Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.

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