Aleutian Tern

Sterna aleuticaOrder: CHARADRIIFORMES Family: Skuas, Gulls, Terns, Skimmers (Laridae)

Codes: Common Name: ALTE Scientific Name: ONYALE ITIS Taxonomic No.: 176893

Breeding Location:

Coastal bays

Breeding Type:

Monogamous

Breeding Population:

Uncommon to locally common

Egg Color:

Olive to buff with dark brown markings

Number of Eggs:

1 - 3

Incubation Days:

22 - 23

Egg Incubator:

Both sexes

Nest Material:

Lined with plant material.

Migration:

Migratory

General

Aleutian Tern: A medium-sized tern with white forehead, black cap, bill, and legs, and gray underparts and upperparts contrasting with pure white rump and tail. Undertail coverts, cheeks, and area immediately below cap are also white. Wing projects slightly beyond tip of tail at rest. In flight, underwing has dark subterminal bar on secondaries, pale area on inner primaries, and dark-tipped outer primaries; upperwing shows bold white leading edge and broad dusky lines on at least 5 to 6 outer primaries when spread. Juvenile is buff and brown on top and flanks, with pale gray underparts; legs and lower mandible are tinted red.

Range and Habitat

Aleutian Tern: This bird breeds in coastal areas of southern and western Alaska. Breeding colonies located along coast of Chukchi Sea, on Seward Peninsula, along Alaska Peninsula, in widely scattered locations in Aleutian Islands, in Kodiak Archipelago, on Kenai Peninsula and Copper River delta, and along Gulf of Alaska. Breeding colonies are located on flat vegetated islands, dwarf-shrub tundra, grass and sedge meadows, sandy spits and islands, and freshwater marshes. Aleutian Tern is not known to winter in North America.

Breeding and Nesting

Aleutian Tern: One to three olive to buff eggs with dark brown markings are laid in a depression on the ground, near water. Nest is lined with plant matter, including moss and matted grasses. Incubation ranges from 22 to 23 days and is carried out by both sexes. Both parents feed the young.

Foraging and Feeding

Aleutian Tern: Usually forages in shallow water, including tidal rips, along rivers, and over inshore marine waters. Occasionally adults and fledglings catch insects by hawking over freshwater ponds and marshes. Searches for food from moderate heights, by swooping down to pick prey items from the surface; by hovering and diving to shallow depths; and by sitting on the surface and dipping. Eats primarily fish and zooplankton.

Vocalization

Aleutian Tern: Call is a carrying staccato "chif-chif-chu-ak", which is more shorebird-like than ternlike. Also gives a short, sharp "chit." Calls from the air and on the ground at colonies. Generally silent while incubating.

Similar Species

Aleutian Tern: In Alaska, it might be confused with similarly-sized Arctic and Common Terns. The Aleutian Tern has a distinctive white forehead and a dark bar on the secondaries while Arctic Tern Breeding Adult has a black forehead and crown which extend onto nape.

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Bird Call Credits: The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology. Martyn Stewart, http://www.naturesound.org, Redmond, Washington USA. The reuse or copying of bird calls in this database is strictly forbidden.

Aleutian Tern

Aleutian Tern: A medium tern, with white forehead, black cap, bill, and legs, gray under and upperparts, white rump and tail. Undertail coverts, cheeks, and area below cap are white. Wing projects beyond tip of tail at rest. Strong direct flight with deep wing beats, often high above water.

● Song: "twee-ee-ee, chif-chu-ak", "chip"

● Foraging & Feeding: Aleutian Tern: Usually forages in shallow water, including tidal rips, along rivers, and over inshore marine waters. Occasionally adults and fledglings catch insects by hawking over freshwater ponds and marshes. Searches for food from moderate heights, by swooping down to pick prey items from the surface; by hovering and diving to shallow depths; and by sitting on the surface and dipping. Eats primarily fish and zooplankton.

● Breeding & nesting: Aleutian Tern: One to three olive to buff eggs with dark brown markings are laid in a depression on the ground, near water. Nest is lined with plant matter, including moss and matted grasses. Incubation ranges from 22 to 23 days and is carried out by both sexes. Both parents feed the young.

● Similar species: Aleutian Tern: In Alaska, it might be confused with similarly-sized Arctic and Common Terns. The Aleutian Tern has a distinctive white forehead and a dark bar on the secondaries while Arctic Tern Breeding Adult has a black forehead and crown which extend onto nape.

Flight Pattern

Strong direct flight with graceful deep wing beats often high above water., Often hovers before dipping into water for food.

● Range & Habitat: Aleutian Tern: This bird breeds in coastal areas of southern and western Alaska. Breeding colonies located along coast of Chukchi Sea, on Seward Peninsula, along Alaska Peninsula, in widely scattered locations in Aleutian Islands, in Kodiak Archipelago, on Kenai Peninsula and Copper River delta, and along Gulf of Alaska. Breeding colonies are located on flat vegetated islands, dwarf-shrub tundra, grass and sedge meadows, sandy spits and islands, and freshwater marshes. Aleutian Tern is not known to winter in North America.

^BreedingMonogamous

^PopulationUncommon to locally common

^MigrationMigratory

^Weight4.2 Ounces

Underparts

Belly, undertail coverts, chest, flanks, and foreneck.

Undertail coverts

Small feathers that cover the areas where the retrices (tail feathers) attach to the rump.

Upperparts

Back, rump, hindneck, wings, and crown.

Cap

The area on top of the head of the bird.

Inner primaries

The inner primaries are a group of feathers closest to the body on the wing of the bird. They are generally covered partially by the secondaries.

Lower mandible

The lower part of the bill.

Outer primaries

The outer primaries are the primary feathers on the wing farthest from the body. They often appear to be the longest feathers on the wing.

Primaries

The primaries are the flight feathers specialized for flight. They are attached to the "hand" equivalent part of the wing.

Rump

The area between the uppertail coverts and the back of the bird.

Secondaries

Flight feathers that are attached to the wing in the area similar to the human forearm and between the body and the primaries.

4 and 6 letter alpha codes

The four letter common name alpha code is is derived from the first two letters of the common first name and the first two letters of common last name. The six letter species name alpha code is derived from the first three letters of the scientific name (genus) and the first three letters of the scientific name (species). See (1) below for the rules used to create the codes..

Four-letter (for English common names) and six-letter (for scientific names) species alpha codes were developed by Pyle and DeSante (2003, North American Bird-Bander 28:64-79) to reflect A.O.U. taxonomy and nomenclature (A.O.U. 1998) as modified by Supplements 42 (Auk 117:847-858, 2000) and 43 (Auk 119:897-906, 2002). The list has been updated by Pyle and DeSante to reflect changes reported by the A.O.U from 2003 through 2006.

Field Guide to Birds of North America

Aleutian Tern

Breeding Location:

Breeding Type:

Breeding Population:

Egg Color:

Number of Eggs:

Incubation Days:

Egg Incubator:

Nest Material:

Migration:

Recommended Products:

General

Range and Habitat

Breeding and Nesting

Foraging and Feeding

Vocalization

Similar Species

Aleutian Tern

Flight Pattern