Little tern

The little tern (Sterna albifrons) is the smallest of the European terns. It breeds along almost the entire Atlantic coast although it is absent from northern Europe, including Scandinavia and Iceland. In Great Britain the largest colonies are found on the east coast of England and at Langstone Harbour in Hampshire. European populations winter on coasts surrounding the Indian Ocean, such as the more northerly parts of East Africa. Populations of little terns, in several subspecies, are found on temperate coasts in other parts of the world such as East Asia and Australia.

Little terns inhabit sandy or marshy areas bordering lakes and rivers, and shingle banks near estuaries and the sea. They are rarely found far inland.

Little terns leave for their winter quarters in August, although some will stay until September if conditions are favourable.

The little tern has amber conservation status in the UK due to the vulnerability of its nesting sites and a general decline in numbers throughout Europe.

Appearance

Male and female little terns are very similar in appearance, being about 23-25 centimetres (9.5 inches) long. They are slim and squat, with narrow wings, a short-forked tail, orange legs and a yellow bill with a black tip. In summer the forehead is bright white against the black of the crown and back of the head and in a stripe from the bill to behind the eye. The rest of the head is white, as is the throat, chest and underparts. The upperparts are blue-grey. The wings are varying shades of grey, with the forewings being darkest. In winter most, but not all, of the black markings are replaced by white or grey.

Behaviour

The little tern is a fast flyer with rapid, flickering wing-beats and it can be seen hovering before diving. It is less gregarious than other terns.

The little tern’s call is a high-pitched “kree-ik” or a harsher “kitik”, although it is most noticeable for its chattering “kirr-wirri”.

The food of the little tern is mainly small fish, taking by diving, but other food can be invertebrates and crustaceans. Insects are taken both on the wing and from the ground.

Breeding

Little terns return to their breeding grounds in late April or early May, when they perform a courtship ritual that consists of the male offering the female a fish and then flying high, pursued by the female until he glides back down.

Little terns breed in small colonies, sometimes shared with other species such as Kentish plovers, with the nests spaced well apart. The nest is a shallow depression that is sometimes lined with small stones or shells. The single clutch, laid around mid-May to early July, is usually of two eggs (sometimes three) that are well camouflaged. The female does most of the incubating, although the male sometimes helps.

The chicks hatch after about 21 days and, for the first few days, are kept warm by the female little tern while the male brings them food. Later they are fed by both parents. 

© John Welford