Black Tern
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| Chlidonias niger (Linnaeus, 1758) |
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The Black Tern, Chlidonias niger, is a small tern.
Length 25 cm (9.75 in), wing span 61 cm (24 in), weight 62 g (2.2 oz).
Adult birds 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 American race, C. n. surinamensis, is distinguishable from the European form in all plumages, and is considered by some to be a separate species.
Their breeding habitat is freshwater marshes across most of Canada, 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.
In flight, the build appears slim. The wing-beats are full and dynamic.
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.
The North American population has declined in recent times due to loss of habitat.
Point Pele Provincial Park in Canada boasts a robust population of black terns. Mother terns can get pretty protective of their young, so you might find yourself fending off terns during spring visits to the park. Warning signs are posted.
The Black Tern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
[edit] References
- BirdLife International (2004). Chlidonias niger. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 09 May 2006. Database entry includes justification for why this species is of least concern
- "National Geographic" Field Guide to the Birds of North America ISBN 0-792-26877-6
- Seabirds, an Identification Guide by Peter Harrison, ISBN 0-7470-8028-8
- Handbook of the Birds of the World Vol 3, Josep del Hoyo editor, ISBN 84-87334-10-5
- "National Audubon Society" The Sibley Guide to Birds, by David Allen Sibley, ISBN 0-679-45122-6
