Sandwich Tern

Sterna sandvicensis

36-41cm

Appearance

This is the biggest tern that breeds in the region. It appears quite robust, it has a black bill with a yellow tip, its legs are short and black, and it has a forked tail with no streamers. In summer the wings and back are light grey, it has a dark cap with a rough crest and the rest of the plumage is white. Forewings show grey wedges. Black cap is perfect only at start of breeding season, and soon shows white speckling above the eyes. When flying, wings can appear uniformly white, but on closer inspection the outer edges are dark. Winter birds lose the dark cap. Juveniles resemble winter adults but they have dark brownish dots on the forehead, and the back has a barred, scaly appearance. The bill is entirely black.

Habitat

This is a coastal bird who breeds on beaches or on islands near to the shore. Rarely seen inland, when not in breeding season it prefers inshore waters.

Character

Regularly flies at higher altitude than most other terns, and its head and bill angle downwards in flight. It dives for food and can be submerged for some time. Colonies may move from one site to another with no obvious motivation.

Food

Diet includes fish that dwell near the sea's surface, such as sand eels, sprats and whiting.

Breeding

A colonial breeder, female lays 1or 2 eggs at the start of April. Both parents incubate eggs for 21-29 days. Hatchlings may remain in the nest, form creches, or roam the colony, but they're fed by their parents until they're able to fly at 28-30 days old; they remain dependent for 3 months.

Population

This is one of the first summer visitors to arrive in the region during the spring. By October majority of birds have left British and Irish territories and most of them travel along the coast of Europe and Africa. The return begins in February and carries through until April. Approximately 12 500 pairs breed in the UK and 2400 in Ireland, though numbers have a large variance from year to year.

Observation Tips

The Sandwich Tern's call is diagnostic, and often give away its presence before the bird is seen. While they are most often seen singly or in pairs, abundant feeding areas may attract larger groups. The south and east of England have the best spots for observation, and birds may be more numerous after a southeasterly wind.

Voice

This is quite a vocal bird, the most regularly heard call being a shrill 'keer-urrick' call.
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