The spectacled tern, also known as the grey-backed tern, is a seabird in the family Laridae.
Region
Central and Eastern Tropical Pacific
Typical Environment
Primarily pelagic, occurring over warm oceanic waters around atolls and archipelagos such as the Line and Phoenix Islands, the Tuamotus, Society and Marquesas Islands, and other central Pacific groups. Breeds on low coral cays, sandy spits, and small vegetated islets, often with little freshwater and sparse cover. Foraging typically takes place offshore along fronts, reef edges, and areas of localized upwelling. Outside the breeding season, birds disperse widely across the tropical Pacific but remain associated with warm waters.
Altitude Range
Sea level to 100 m
Climate Zone
Tropical
Ease of Keeping
Beginner friendly: 1/5
The spectacled tern, also called the grey-backed tern, gets its name from the thin white eye-ring and pale crescents that give a ‘spectacled’ look. It breeds in large colonies on remote coral cays and sandy islets across the tropical Pacific. Often confused with the sooty tern, it is paler above with a distinctly grey back. Colonies are vulnerable to disturbance and introduced predators such as rats and cats.
Temperament
social and active
Flight Pattern
buoyant, agile flight with rapid wingbeats and short glides
Social Behavior
Breeds colonially, often in dense mixed-age groups on open sand or low vegetation. Nests are simple scrapes; both parents incubate and feed the chick. Outside the breeding season, birds form loose flocks at sea and may associate with other terns and feeding predatory fish.
Migratory Pattern
Partial migrant
Song Description
Vocalizations are sharp, chattering calls and harsh rasping notes given in flight and around colonies. Alarm calls are rapid, scolding series, while contact calls are shorter, higher-pitched chips.
Plumage
Smooth grey upperparts with clean white underparts and a contrasting black cap. The face shows a fine white eye-ring and pale crescents that create a ‘spectacled’ appearance. Upperwings are grey with darker outer primaries; tail moderately forked.
Diet
Feeds mainly on small schooling fish and cephalopods, taking prey near the surface. It also snatches marine invertebrates and occasionally small crustaceans. Birds often forage in association with tuna or dolphins that drive prey to the surface.
Preferred Environment
Most feeding occurs over open ocean, along current lines, reef margins, and areas with floating debris that concentrate prey. Near colonies, birds may forage just offshore in productive lagoons or passes.
