Black Tern

from Wikipedia, the free encyclopedia
Black Tern
Black tern (here the American subspecies Chlidonias niger surinamensis)

Black tern (here the American subspecies Chlidonias niger surinamensis )

Systematics
Class : Birds (aves)
Order : Plover-like (Charadriiformes)
Family : Terns (Sternidae)
Genre : Common Terns ( Chlidonias )
Type : Black Tern
Scientific name
Chlidonias niger
( Linnaeus , 1758)
Flight image
Flight image

The black tern ( Chlidonias niger ) is a species of bird in the family of the tern (Sternidae) that occurs in the Holarctic .

description

The black tern reaches a body length of up to 25 centimeters. It is therefore significantly smaller than the common tern. There is no noticeable sexual dimorphism .

In the splendid dress, the head, chest and belly are jet black and the top of the body is gray. The underside of the wings is light gray, the rear underside of the body is blackish gray, while the under tail-coverts are white. In the plain dress, the top is dark gray, the bottom is white. There is a dark spot on each side of the chest in front of the base of the wings. Their pointed beak is black and their feet are red and black.

In the plain dress, the black tern is very difficult to distinguish from the white-bearded tern and the white-winged tern when observing outdoors . The white-bearded tern, however, is slightly larger than the black tern and has a more powerful beak. The white-winged tern does not have a black spot on the sides of the chest.

The nestlings are place stools. Freshly hatched, they have long and soft down with a fine and silky tip. They are colored clay-yellow to cinnamon-brown with black spots on the upper side of the body as well as on the chin and throat. The center of the chest is grayish white. The flanks and the belly are reddish gray. In newly hatched nestlings, the beak is black with a pink base. The beak of young birds that fly out is completely black. The legs and feet are pink with a gray tinge at all ages.

The black tern's call sounds like “kiek” or “kik kik”. The flight is wobbly and arched, often it only flies low over the water surface.

Distribution area and habitat

The distribution area of ​​the Black Tern is North America and Eurasia. In Central Europe, the Black Tern is a rare breeding bird, but it can be seen regularly as a migrant and sometimes frequently in many inland waters. The black tern is a long-distance migrant, the European populations overwinter on the coasts of tropical Africa.

The black tern lives from April to September at the edge of water , e.g. B. swamps , shallow lakes and moors in Eastern , Southern and Central Europe . They have their winter quarters on the coasts of tropical West Africa . In Germany only about 760 breeding pairs were counted in 2005.

nutrition

The black tern feeds on fish , amphibians and insects . The main food is dragonflies, especially dragonflies. They prey on their food in flight from the air or from the surface of the water. Black terns occasionally stay shaking in the air for a long time or even fly a little bit backwards.

Reproduction

Egg ( Museum Wiesbaden Collection )

The Black Tern breeds in sweet and brackish inland waters overgrown with aquatic plants; Black Terns usually breed in colonies. The nest is built on floating piles of plant parts that are anchored to aquatic plants or on stalks of reeds and bent reeds, as well as on solid ground in swamp vegetation in swamp areas. The breeding season begins in the south of the distribution area in mid-May, in the northern part of the distribution area from the end of May. Usually only one brood is raised.

The female lays two to three dark-spotted eggs . These are oval to top-shaped and have a smooth, slightly shiny surface. The basic color is light beige, cream-colored to light brown. They have irregular spots and blobs that are mostly concentrated on the blunt pole of the egg. The laying interval is one to two days, the eggs are incubated by both parent birds, which start the breeding business after the last egg has been laid. The breeding season is 20 to 22 days. The young birds are looked after by both parent birds and stay on the nest for about two weeks. They fledge at 25 to 28 days, but are still fed by the parent birds. They leave the breeding colony with their parent birds around the age of six weeks.

Endangerment and protection status

The global stock situation of the Tern was in 2016 in the endangered Red List species of IUCN in the category of " Least Concern (LC) " not at risk "" = classified.

The black tern is threatened with extinction in some parts of its range. The most common reasons for the losses are humans and the few undisturbed breeding sites. Experience in recent years has also shown that larger colonies offer better protection for clutches and especially for young birds, because a large number of adult birds are obviously better able to protect themselves from most predators such as carrion crows or mink , which are responsible for this in colonies with fewer than 10 breeding pairs are that a young bird rarely, if ever, fledged. In the larger colonies, the loss of clutches or young birds can only be assessed as very low. For the breeding business to run successfully, dangers such as boat operations, fishing and other leisure activities must be excluded.

In Germany, the black tern is considered critically endangered ( red list category 1 ). It is a species in Appendix I of the EU Birds Directive (RL 79/409 / EEC).

literature

Web links

Commons : Black Tern  - Album with pictures, videos and audio files

Single receipts

  1. Bezzel., P. 287
  2. Harrison et al., P. 171
  3. Bezzel, p. 286
  4. Bezzel, p. 287
  5. Harrison et al., P. 170
  6. ^ Harrison, p. 171
  7. Chlidonias niger in the endangered Red List species the IUCN 2016 Posted by: BirdLife International, 2016. Retrieved on October 10, 2017th
  8. Christoph Grüneberg, Hans-Günther Bauer, Heiko Haupt, Ommo Hüppop, Torsten Ryslavy, Peter Südbeck: Red List of Breeding Birds in Germany, 5th version . In: German Council for Bird Protection (Hrsg.): Reports on bird protection . tape 52 , November 30, 2015.