Black Tern
Encyclopedia
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.
The North America
n race, C. n. surinamensis, is distinguishable from the European form in all plumages, and is considered by some to be a separate species.
In flight, the build appears slim. The wing-beats are full and dynamic, and flight is often erratic as it dives to the surface for food; similar to other tern species.
, 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).
, the northern United States
and much of Europe
and western Asia
. They usually nest either on floating material in a marsh or on the ground very close to water, laying 2-4 eggs.
North American Black terns migrate
to the coasts of northern South America
, some to the open ocean. Old World birds winter in Africa
.
Unlike the "white" Sterna terns, these birds do not dive for fish, but forage on the wing picking up items at or near the water's surface or catching insects in flight. They mainly eat insects and fish as well as amphibians.
Point Pelee National Park
in Canada
boasts a robust population of black terns.
The Black 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 inland water in 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...
and 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...
. As its name suggests, it has predominantly dark plumage.
Description
Adult are 25 cm (9.75 in) long, with a wing span 61 cm (24 in), and weigh 62 g (2.2 oz). They have short dark legs and a short, weak-looking black bill, measuring 27–28 mm, nearly as long as the head. The bill is long, slender, and looks slightly decurved. They have a dark grey back, with a white forehead, black head, neck (occasionally suffused with gray in the adult) and belly, black or blackish-brown cap (which unites in color with the ear coverts, forming an almost complete hood), and a light brownish-grey, 'square' tail. The face is white. There is a big dark triangular patch in front of the eye, and a broadish white collar in juveniles. There are grayish-brown smudges on the ides of the white breast, a downwards extension of the plumage of the upperparts. These marks vary in size and are not conspicuous. In non-breeding plumage, most of the black, apart from the cap, is replaced by grey. The plumage of the upperparts is drab, with pale feather-edgings. The rump is brownish-gray.The 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...
n race, C. n. surinamensis, is distinguishable from the European form in all plumages, and is considered by some to be a separate species.
In flight, the build appears slim. The wing-beats are full and dynamic, and flight is often erratic as it dives to the surface for food; similar to other tern species.
Hybridisation with White-winged Black Tern
Hybridisation between this species and White-winged Black Tern has been recorded from Sweden and the Netherlands. Two juvenile birds at Chew Valley LakeChew 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 most of CanadaCanada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, the northern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and much of 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...
and western 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 material in a marsh or on the ground very close to water, laying 2-4 eggs.
North American Black terns 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 the coasts of northern South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, some to the open ocean. Old World birds winter in 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...
.
Unlike the "white" Sterna terns, these birds do not dive for fish, but forage on the wing picking up items at or near the water's surface or catching insects in flight. They mainly eat insects and fish as well as amphibians.
Vagrancy
The American race has occurred as a vagrant in Britain and in Ireland.Conservation
The North American population has declined in recent times due to loss of habitat.Point Pelee National Park
Point Pelee National Park
-See also:*National Parks of Canada*List of National Parks of Canada*Long Point-External links:**...
in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
boasts a robust population of black terns.
The Black 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.
External links
- Black Tern Childonias niger - USGS Patuxent Bird Identification InfoCenter
- Black Tern Species Account - Cornell Lab of Ornithology
- Black Tern Information and Photos - South Dakota Birds and Birding
- Avibase