Arctic tern (Sterna paradisaea): migration, appearance, and range

Description

Arctic terns are slim, graceful birds with long, narrow wings and a deeply forked tail that can appear elongated in flight. Adults have pale grey upperparts, white underparts, a distinctive black cap, and red bill and legs. Their plumage and flight style—light, buoyant, and acrobatic—make them well adapted to life over marine and coastal waters. They feed mainly on small fish and marine invertebrates, which they catch by plunge-diving or surface-dipping.

Migration and movement

Perhaps the species' best-known trait is its migratory behaviour. Arctic terns breed in Arctic and sub-Arctic summers and then travel to Antarctic waters for the southern summer, effectively experiencing more daylight than almost any other animal. Satellite and tracking studies have recorded individuals covering very long annual distances—studies often cite round-trip totals of roughly 70,900 kilometres—by following a variety of coastal and oceanic routes that exploit prevailing winds and food availability.

Breeding, behaviour and ecology

Arctic terns nest in open sites on the ground, from rocky shores to tundra and islands, commonly forming loose colonies. They lay a small clutch of eggs and fiercely defend their nest sites from intruders. Pairs cooperate in incubation and chick-rearing, and young fledge after several weeks. Lifespans extend for many years in the wild, and individuals may undertake thousands of kilometres of migration annually over a long adult life span.

Cultural significance and conservation

The species appears on postage stamps and in the cultural life of many northern communities: examples include stamps and depictions associated with the postage stamp collections of various countries and dependent territories. Specific issuers that have featured the Arctic tern include the Åland Islands, Alderney and the Faroe Islands, and national issues such as those from Canada, Finland, Iceland and Cuba. Conservation status varies regionally: many colonies remain stable, while others face pressure from habitat change, increased predation, and human disturbance. Ongoing monitoring and local protection efforts help track population trends and mitigate threats.

• Key traits: long wings, forked tail, black cap, red bill and legs.
• Diet: small fish and marine invertebrates.
• Range: Arctic/sub-Arctic breeding; Antarctic wintering.