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Thalasseus bengalensis

Summary 7

The Lesser Crested Tern (Thalasseus bengalensis, syn. Sterna bengalensis - see Bridge et al., 2005) is a seabird of the tern family Sternidae. It breeds in subtropical coastal parts of the world mainly from the Red Sea across the Indian Ocean to the western Pacific, and Australia, with a significant population on the southern coast of the Mediterranean on two islands off the Libyan coast. Accidental breeding has also been reported in Italy and France. The...

General description 8

The summer adult has a black cap, black legs and a long sharp orange bill. The upperwings, rump and central tail feathers are grey and the underparts white. The primary flight feathers darken during the summer. In winter, the forehead becomes white. The call is a loud grating noise like Sandwich Tern.The grey rump is a useful flight identification feature distinguishing it from the related species. The Elegant Tern also differs in a slightly longer, slenderer bill, while Chinese Crested Tern differs in a black tip to the bill and Sandwich Tern a black bill with a yellow tip. Juvenile Lesser Crested Terns resemble same-age Sandwich Terns, but with a yellow-orange bill, and paler overall, with only faint dark crescents on the mantle feathers.

Range description 9

The Lesser Crested Tern breeds in subtropical coastal parts of the world mainly from the Red Sea across the Indian Ocean to the western Pacific, and Australia, with a significant population on the southern coast of the Mediterranean on two islands off the coast of Libya. Outside the breeding season it ranges on the north African coast (both Mediterranean and Atlantic), on much of the Indian Ocean nearby continents, and in the western Pacific north of Australia up to New Guinea and Vietnam1.

Size 10

This is a medium-large tern, very similar in size and general appearance to its three very close relatives Sandwich Tern, Elegant Tern and Chinese Crested Tern.

Habitat and ecology 11

Habitat and Ecology

Behaviour The details of this species's movements are poorly known although some breeding populations appear to be migratory (del Hoyo et al. 1996). The species breeds in large dense colonies of up to 20,000 pairs (del Hoyo et al. 1996) often with other species (del Hoyo et al. 1996). It is gregarious throughout the year, foraging in single- or mixed-species flocks up to 400 individuals (del Hoyo et al. 1996, Snow and Perrins 1998). Habitat The species inhabits tropical and subtropical (del Hoyo et al. 1996) sandy and coral coasts and estuaries (Urban et al. 1986), breeding on low-lying offshore islands, coral flats, sandbanks (del Hoyo et al. 1996) and flat sandy beaches (Snow and Perrins 1998), foraging in the surf and over offshore waters (del Hoyo et al. 1996). Diet Its diet consists predominantly of small pelagic fish (Urban et al. 1986, del Hoyo et al. 1996) and shrimps (del Hoyo et al. 1996). Breeding site The nest is a shallow scrape (del Hoyo et al. 1996) on ridges or bare areas surrounded by vegetation (del Hoyo et al. 1996) on flat sandy beaches (Snow and Perrins 1998), low-lying sandy islands, coral flats, small coral islets and sandbanks (del Hoyo et al. 1996).

Systems
  • Terrestrial
  • Marine

Behaviour 12

Reproduction 13

May-Jun in Persian Gulf, May-Jun in N Australia

Iucn red list assessment 14


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2012

Assessor/s
BirdLife International

Reviewer/s
Butchart, S. & Symes, A.

Contributor/s

Justification
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Sources and Credits

  1. (c) Jerry Oldenettel, some rights reserved (CC BY-NC-SA), http://www.flickr.com/photos/7457894@N04/6074261469
  2. (c) Sandeep Gangadharan, some rights reserved (CC BY), https://upload.wikimedia.org/wikipedia/commons/8/84/OneSandwichAmongLesserCrestedTerns.jpg
  3. (c) 林淑然, some rights reserved (CC BY-NC-SA), http://csdb.ioz.ac.cn/images/Upload_images/Animalia/Chordata/Aves/Lariformes/Stercorariidae/Thalasseus/bengalensis/68155554-B042-4D27-A97A-B98EE9C6D6F4.jpg
  4. (c) Carmelo López Abad, some rights reserved (CC BY-NC), uploaded by Carmelo López Abad
  5. (c) Ryan McFarland, some rights reserved (CC BY-NC), uploaded by Ryan McFarland
  6. (c) Katerina Tvardikova, some rights reserved (CC BY-NC-SA), http://pngbirds.myspecies.info/sites/pngbirds.myspecies.info/files/SterBeng_0.jpg
  7. (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Thalasseus_bengalensis
  8. (c) New Guinea Birds, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/26403979
  9. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31285366
  10. (c) New Guinea Birds, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/26403982
  11. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31285368
  12. (c) New Guinea Birds, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/26403975
  13. (c) New Guinea Birds, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/26403981
  14. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31285365

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(c) Discover Life and original sources, some rights reserved (CC-BY-NC-SA)

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