The Aleutian tern is a migratory bird living in the subarctic region of the globe most of the year. It is frequently associated with the Arctic tern, which it closely resembles. While both species have a black cap, the Aleutian tern may be distinguished by its white forehead. During breeding season, the Arctic terns have bright red bills, feet, and legs while those of the Aleutian terns are black.
Region
North Pacific Rim and Southeast Asia
Typical Environment
Breeds along coastal western Alaska, the Aleutian and Bering Sea islands, and across the Russian Far East including Kamchatka and Sakhalin. During the non-breeding season it migrates to tropical coastal waters of Southeast Asia, with concentrations reported around the South China Sea, Java Sea, and Strait of Malacca. Typical habitats include coastal tundra, river deltas, lagoons, sandy spits, and estuaries. It forages mainly in nearshore marine waters and sheltered bays, occasionally over freshwater near colonies.
Altitude Range
Sea level to 200 m
Climate Zone
Other
Ease of Keeping
Beginner friendly: 1/5
This subarctic tern closely resembles the Arctic tern but is readily told by its crisp white forehead contrasting with a black cap. It breeds in coastal Alaska and the Russian Far East and then undertakes a long migration to winter along tropical coasts of Southeast Asia. At colonies it is quieter and more secretive than Arctic terns, often nesting in loose groups on sandy or tundra margins.
Adult Onychoprion aleuticus in breeding plumage in Nome, Alaska.
Map of the Chukchi Sea (Western Alaska).
Parasitic Jaeger (Stercorarius parasiticus) on an ice floe, Svalbard.
Arctic tern (Sterna paradisaea) attacking to protect its offspring, Svalbard.
Temperament
social and colonial
Flight Pattern
agile flier with buoyant wingbeats and brief glides
Social Behavior
Nests in loose colonies, sometimes mixed with Arctic terns, on open sand, gravel bars, or low tundra near water. A shallow scrape serves as the nest, typically holding two eggs. Both parents incubate and feed the chicks, and adults may perform distraction displays when threatened.
Migratory Pattern
Seasonal migrant
Song Description
Calls are softer and more nasal than those of Arctic terns, including rapid chitters and kek-kek notes around colonies. In flight it gives thin, high-pitched contact calls that carry over surf and wind.
Plumage
Smooth grey upperparts with paler grey underparts; clean white forehead contrasting with a black cap in breeding plumage; dark primary wedge on upperwing and pale trailing edges. Non-breeding birds show more extensive white on the forehead and a duller cap.
Diet
Feeds primarily on small schooling fish such as sand lance and juvenile herring, and also takes small crustaceans and marine invertebrates. It forages by shallow plunge-diving, surface-dipping, and hawking near the water surface. Occasionally it captures aerial insects over rivers or lagoons near breeding sites.
Preferred Environment
Nearshore marine waters, tidal rips, estuaries, and lagoons where baitfish aggregate. Often works current lines and sheltered bays, especially near river mouths and sandbars.
