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Black-bellied Tern Sterna acuticauda
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This species is almost extinct in a large part of its range and is thought to be in very rapid decline overall, owing to a multitude of threatening processes that affect riverine species in southern Asia. It has therefore been uplisted to Endangered.

Taxonomic source(s)
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

Taxonomic note
The BirdLife Taxonomic Working Group is aware that phylogenetic analyses have been published which have proposed generic rearrangements which may affect this species, but prefers to wait until work by other taxonomists reveals how these changes affect the

33 cm. Small tern. Breeding adults have orange bill, black cap and nape, dark grey breast and blackish belly and vent. Non-breeding birds show a whitish belly and lack tail streamers and the orange bill has a dark tip. Similar spp Told from other terns by smaller size and orange bill. Voice A clear piping "peuo".

Distribution and population
Sterna acuticauda is known from southern China (previously regular in Yunnan, now very rare), Pakistan (fairly common in north Sind and Punjab), India (widespread and locally fairly common, but some evidence for localised declines), Nepal (once locally fairly common, declining since the early 1990s at least, and judged to be a rare and very local visitor in the lowlands, with a maximum population of 20 estimated in 2011 [C. Inskipp and H. S. Baral in litt. 2011]), Bangladesh (previously common, now a local breeder; the provenance of some recent records has been questioned [P. Thompson in litt. 2011]), Myanmar (previously abundant, now declining rapidly and a scarce to uncommon resident, with some surveys since 2002 failing to record the species at all [J. C. Eames in litt. 2012]), Thailand (formerly resident in the north-west, now very rare and probably extinct as breeding species), Laos (previously bred in large numbers along the Mekong channel, now very rarely recorded), Cambodia (in early 1960s the species was apparently fairly common along the Mekong; the last breeding record was of just two pairs in 2003 [C. Poole in litt. 2003], and it is now considered probably extinct there [Goes et al. 2010]) and Vietnam (formerly occurred regularly in Cochinchina, and occasionally in Annam, but now probably extinct). There has been a precipitous decline in South-East Asia and it is now almost extinct in the region. Despite its large range, the species may now number fewer, perhaps significantly fewer, than 10,000 mature individuals (Perennou et al. 1994, S. Mahood in litt. 2012).

Population justification
Despite its large range, the species could now number fewer, perhaps significantly fewer, than 10,000 mature individuals (Perennou et al. 1994, S. Mahood in litt. 2012), although this may be over-cautious (BirdLife International 2001). The population estimate is currently placed at 10,000-25,000 individuals, roughly equating to 6,700-17,000 mature individuals, until more data are available.

Trend justification
A very rapid and on-going decline is suspected based on the comparison of its current rarity and former abundance in many parts of its range, as well as the prevalence of a multitude of threats.

It is found on large rivers (usually breeding on sandspits and islands) and marshes, occasionally on smaller pools and ditches, in lowlands (but not on the coast), up to 730 m.

Threats include the destruction of breeding habitat (islands and sandspits in larger rivers are increasingly cultivated), the collection of eggs for food, overfishing and the flooding of nests, often caused by dams. Increased disturbance and over-harvesting of wetland products are blamed for the recent complete disappearance of the breeding population within Chitwan National Park (Nepal) (F. Cuthbert in litt. 2002). River damming, disturbance, predation by dogs and egg collecting are highlighted as causes of the species’s disappearance from Cambodia (Goes et al. 2010). In India, the species faces many threats, which include, in addition to those already listed, water extraction, sand and gravel extraction for development, disturbance and predation by cats, dogs and corvids, such as House Crows Corvus splendens, which are attracted to human settlements, pollution from industry and agriculture, and mortality through fisheries bycatch (A. Rahmani in litt. 2010, S. Mahood in litt. 2012).

Conservation Actions Underway
It is known from a number of protected areas throughout its range, including Harike Wildlife Sanctuary, Keoladeo National Park, Rajiv Gandhi National Park, Dibru-Saikhowa National Park and Kaziranga National Park. Conservation Actions Proposed
Organise a population census in Pakistan, India, Bangladesh and Nepal during the breeding season, and conduct further surveys in Myanmar to clarify its current distribution and status. Monitor population trends through regular surveys across its range. Carry out awareness-raising activities to alleviate human pressures on riverine ecosystems. Campaign for increased representation of large waterways in protected-area systems.

BirdLife International. 2001. Threatened birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, U.K.

Goes, F.; Claassen, A.; Nielsen, H. 2010. Letter to the Editor - Obituary to the Black-bellied Tern. Cambodian Journal of Natural History 1: 5-6.

Perennou, C. P.; Mundkur, T.; Scott, D. A. 1994. The Asian Waterfowl Census 1987-1991: distribution and status of Asian waterfowl. IWRB and AWB, Slimbridge and Kuala Lumpur.

Sykes, B. 2010. River terns: is the Black-bellied Tern Sterna acuticauda heading to oblivion? BirdingASIA 13: 73.

Further web sources of information
Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Butchart, S., Mahood, S., Taylor, J.

Baral, H., Cuthbert, F., Davidson, P., Duckworth, W., Eames, J., Htin Hla, T., Inskipp, C., Khan, A., Li, Z., Mahood, S., Parveen, A., Poole, C., Praveen, J., Rafeek, K., Rahmani, A., Singh, A., Sundar, G., Thompson, P., Timmins, R. & Yasmeen, R.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2016) Species factsheet: Sterna acuticauda. Downloaded from on 27/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 27/10/2016.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Black-bellied tern (Sterna acuticauda) 0

Key facts
Current IUCN Red List category Endangered
Family Laridae (Gulls, Terns, Skimmers)
Species name author Gray, 1832
Population size 6700-17000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 2,470,000 km2
Country endemic? No
Links to further information
- Additional Information on this species