River Tern (bird)
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| Sterna aurantia Gray,JE, 1831 |
- For the River in Shropshire, England, see River Tern.
The River Tern Sterna aurantia is a bird in the tern family . It is a resident breeder along inland rivers from Iran east through Pakistan into India and Myanmar to Thailand, where it is uncommon. It does not occur in Sri Lanka. Unlike most Sterna terns, it is almost exclusively found on freshwater, rarely venturing even to tidal creeks.
This species breeds from March to May in colonies in less accessible areas such as sandbanks in rivers. It nests in a ground scrape, often on bare rock or sand, and lays three greenish-grey to buff eggs, which are blotched and streaked with brown.
This is a medium-sized tern, 38-43 cm long with dark grey upperparts, white underparts, a forked tail with long flexible streamers, and long pointed wings. The bill is yellow and the legs red. It has a black cap in breeding plumage. In the winter the cap is greyish white, flecked and streaked with black, there is a dark mask through the eye, and the tip of the bill becomes dusky.
The sexes are similar but juveniles have a brown head, brown-marked grey upperparts, grey breast sides and white underparts. The bill is yellowish with a dark tip
As with other Sterna terns, the River Tern feeds by plunge-diving for fish, crustaceans, tadpoles and aquatic insects in rivers, lakes, and tanks. Its numbers are decreasing is due to the pollution of their habitat.
[edit] References
- BirdLife International (2004). Sterna aurantia. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes justification for why this species is of least concern
- Birds of India by Grimmett, Inskipp and Inskipp, ISBN 0-691-04910-6
- Seabirds by Harrison, ISBN 0-7470-8028-8
