White-winged Tern
Encyclopedia
The White-winged Tern, or White-winged Black Tern, Chlidonias leucopterus, is a small tern
generally found in or near bodies of fresh water across from Southeastern Europe
east to Australia
.
The name 'White-winged Tern' is the standard in most English-speaking countries; in Britain, this name is also the one used by the formal ornithological recording authorities, but the older alternative 'White-winged Black Tern' is still frequent in popular use.
has been recorded from Sweden and the Netherlands. Two juvenile birds at Chew Valley Lake
, England
, in September 1978 and September 1981, were also believed to be hybrids; they showed mixed characters of the two species, specifically a combination of a dark mantle (a feature of White-winged Black) with dark patches on the breast-side (a feature of Black Tern, not shown by White-winted Black).
to central Asia
. They usually nest either on floating vegetation in a marsh or on the ground very close to water, laying 2-4 eggs in a nest built of small reed stems and other vegetation. In winter, they migrate
to Africa
, southern Asia and Australia
. It is a scarce vagrant in North America
, mainly on the Atlantic coast, but a few records on the Pacific coast and inland in the Great Lakes area.
The White-winged Tern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA
) applies.
Tern
Terns are seabirds in the family Sternidae, previously considered a subfamily of the gull family Laridae . They form a lineage with the gulls and skimmers which in turn is related to skuas and auks...
generally found in or near bodies of fresh water across from Southeastern Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
east to Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
The name 'White-winged Tern' is the standard in most English-speaking countries; in Britain, this name is also the one used by the formal ornithological recording authorities, but the older alternative 'White-winged Black Tern' is still frequent in popular use.
Description
Adult birds in summer have short red legs and a short black bill (small and stubby, meausuring 22–25 mm from the feathers, decidedly shorter than the head), a black neck (often with a pale gray back) and belly, very dark grey back, with a white rump and light grey (almost white) tail, which often looks 'square' in juveniles. The face is tinged yellowish. The wings, as the name implies, are mainly white. The inner wing is grayish with brown-tipped coverts. In non-breeding plumage, most of the black is replaced by white or pale grey, though a few blackish feathers may be retained, admixed with white underparts. A good deal of black shows in the underwing-coverts. The head is black, with a white forehead. The crown is blackish-brown, flecked with white, and the hindcrown is blackish with a certain amount of white flecking. These white markings are pronounced in the winter adult. There is a dark triangular patch forward of the eye. The collar is fairly broad and white. In juveniles and moulting adults, the rump is pale gray, becoming grey in both phases late in the year. The clear white collar and rump isolate the mantle as a dark brown 'saddle'. The mantle feathers have narrow paler brown tips, as have the tertials and scapulars.Hybridisation with Black Tern
Hybridisation between this species and Black TernBlack Tern
The Black Tern, Chlidonias niger, is a small tern generally found in or near inland water in Europe and North America. As its name suggests, it has predominantly dark plumage.- Description :...
has been recorded from Sweden and the Netherlands. Two juvenile birds at Chew Valley Lake
Chew Valley Lake
Chew Valley Lake is a large reservoir in the Chew Valley, Somerset, England, and the fifth-largest artificial lake in the United Kingdom , with an area of 1,200 acres...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, in September 1978 and September 1981, were also believed to be hybrids; they showed mixed characters of the two species, specifically a combination of a dark mantle (a feature of White-winged Black) with dark patches on the breast-side (a feature of Black Tern, not shown by White-winted Black).
Distribution and habitat
Their breeding habitat is freshwater marshes across from southeast EuropeEurope
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
to central Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. They usually nest either on floating vegetation in a marsh or on the ground very close to water, laying 2-4 eggs in a nest built of small reed stems and other vegetation. In winter, they migrate
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
to Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, southern Asia and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It is a scarce vagrant in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, mainly on the Atlantic coast, but a few records on the Pacific coast and inland in the Great Lakes area.
Behaviour
Like the other "marsh" terns (Chlidonias), and unlike the "white" (Sterna) terns, these birds do not dive for fish, but fly slowly over the water to surface-pick items on the surface and catch insects in flight. They mainly eat insects and small fish. In flight, the build appears thick-set. The wing-beats are shallow and leisurely.The White-winged Tern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA
AEWA
The Agreement on the Conservation of African-Eurasian Migratory Waterbirds is the largest of its kind developed so far under the Bonn Convention. It was concluded on 16 June 1995 at The Hague, the Netherlands and entered into force on 1 November 1999 after the required number of at least fourteen...
) applies.