occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Breeding
Global Range: (200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)) Breeding occurs in coastal areas in Alaska throughout the Aleutian Islands as far west as Attu Island, north to the southeastern Chukchi Sea and east to the Alaska Peninsula, Yakutat, and Glacier Bay (see Haney et al. 1991). Breeding in Asia is mostly confined to regions in or near the Sea of Okhotsk and western Bering Sea; recorded from the Commander Islands, Koraginsky Island, the Kamchatka Peninsula, and Sakhalin Island (Haney et al. 1991). The range during the nonbreeding season is not well known; the species is thought to be wide-ranging at sea; likely it has a tropical western Pacific distribution; recorded in the Philippines (Lee 1992). Recent observations in coastal waters around Hong Kong in spring and fall and Singapore and the Indonesian islands of Karimuna and Bintan between October and April indicate that at least part of the population migrates through and winters in these areas. Other observations suggest that coastal waters of Java, Bali, and Suwalesi may form an additional part of the winter range (Hill and Bishop 1999).
Length: 34 cm
Weight: 120 grams
Catalog Number: USNM 52517
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Birds
Sex/Stage: Male; Adult
Preparation: Skin: Whole
Collector(s): F. Bischoff
Year Collected: 1868
Locality: Kodiak Island, Kodiak Island Division, Alaska, United States, North America
- Type: Baird. (Not Earlier Than October 22) 1869. Trans. Chicago Acad. Sci. 1 (2): 321, pl. 31, fig. 1.
Habitat and Ecology
Comments: NON-BREEDING: pelagic.
BREEDING: Nests on grassy or mossy flats, on small offshore islands and coastal spits, around lagoons or near river mouths; nests frequently are mixed with those of arctic terns. Nests usually on sand spits, sandbar islands, sand dunes, and flat vegetated summits of more rugged islands; on low wet coastal marsh and tundra in some areas; on dry sites covered by thick mats of rotted wood or other vegetation (Haney et al. 1991). Colony locations frequently shift from year to year among traditionally used sites, such that local populations may fluctuate greatly (Haney et al. 1991).
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.
Arrives in eastern Alaska in late April, in western and northern Alaska mid-May to early June; flocks begin to form in staging areas from late July to early August, prior to departure for wintering areas (Haney et al. 1991).
Comments: Summer diet includes mainly small fishes such as capelin and sand lance, also sticklebacks, salmon smolts, smelt, Pacific sandfish, greenling, and euphausiids (Haney et al. 1991). In summer, forages mostly in shallow water such as tide rips near colonies within 1-10 km of land but also well out to sea. Flies at moderate heights, swoops down to surface-pick for prey items (Haney et al. 1991).
10,000 - 100,000 individuals
Comments: Global population estimated at 17,000-20,000 individuals (USFWS 2006). Alaska breeding population estimated at 9,500 birds (USFWS 2006). Siberian population was estimated at about 13,000 individuals in the early 1990s (Haney et al. 1991).
Forages singly, in monospecific flocks, or in mixed-species flocks.
Life History and Behavior
Lays clutch of usually 2 eggs, mid- or late May to late June. Incubation averages 22 days. Hatching occurs mid-June to late July. Young fledge in 4 weeks, mid-July to late August. Young may remain at nest for 1-2 weeks after they are able to fly. Only one brood per season. Reportedly does not attempt to renest if eggs are taken. Nests in loose colonies of a few to over 500 pairs.
Molecular Biology and Genetics
Barcode data: Onychoprion aleuticus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Onychoprion aleuticus
Public Records: 6
Specimens with Barcodes: 7
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N4B - Apparently Secure
NatureServe Conservation Status
Rounded Global Status Rank: G4 - Apparently Secure
Comments: Due to this tern's tendency to concentrate in a few areas, contamination as a result of oil spills is a potential threat. Heavy predation by birds and mammals and mortality associated with exposure to inclement weather may contribute to low reproductive success. Species is sensitive to disturbance at nesting colonies; complete colony abandonment has been observed following a single visit by humans (Haney et al. 1991). Most colonies are isolated and rarely visited, so human disturbance is only a local problem. On nonbreeding range, threats include human overfishing of prey species, uncontrolled waste disposal, and land-based pollution (Haney et al. 1991).
Biological Research Needs: Information is needed on survival, food habits, and habitat use in nonbreeding range. A banding program at breeding colonies is needed to determine colony fidelity and lifetime reproductive success (North 1997).
This species breeds in colonies on coasts and islands in Alaska and easternmost Siberia. It is strongly migratory, wintering off Indonesia and Malaysia. Large numbers appear off China during passage periods.
It lays 2-3 eggs in a ground scrape. It sometimes nests among Arctic terns, which, like most white terns, are fiercely defensive of their nest and young and will attack large predators.
Like most other terns, the Aleutian tern feeds by plunge-diving for fish, usually from saline environments. The offering of fish by the male to the female is part of the courtship display.
This is a medium-sized tern, with a short, pointed bill and a long, deeply forked tail. It has a black cap with a white forehead, dark gray mantle and underparts and a mostly pale underwing with a dark secondary bar. It has a white rump and tail, black legs and a black bill.
The call is a musical whee-hee-hee.
- Bridge, E. S.; Jones, A. W. & Baker, A. J. (2005): A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution. Molecular Phylogenetics and Evolution 35: 459–469. PDF fulltext
- Collinson, M. (2006). Splitting headaches? Recent taxonomic changes affecting the British and Western Palaearctic lists. British Birds 99(6): 306-323.
- del Hoyo, J.; Elliott, A. & Sargatal, J. (editors) (1996): Handbook of birds of the world, Volume 3: Hoatzin to Auks. Lynx Edicions, Barcelona. ISBN 84-87334-22-9
- Harrison, Peter (1988): Seabirds (2nd edition). Christopher Helm, London ISBN 0-7470-1410-8
- National Geographic Society (2002): Field Guide to the Birds of North America. National Geographic, Washington DC. ISBN 0-7922-6877-6
- Sibley, David Allen (2000): The Sibley Guide to Birds. Alfred A. Knopf, New York. ISBN 0-679-45122-6
Names and Taxonomy
Comments: Monotypic. Sterna camtschatica Finch, 1882 is a synonym used by some authors, especially in Russian literature (North 1997). Based on similar head patterns, this species may form superspecies with the gray-backed tern (S. lunata) and bridled tern (S. anaethetus); Aleutian and gray-backed tern also have similar foot and bill structure (Cramp 1985). This species formerly (AOU 1983, 1998) was included in the genus Sterna, but it is now placed in Onychoprion on the basis of genetic data that correspond to plumage patterns (Bridge et al. 2005).