Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Laridae

Scientific Name: Sterna sumatrana
Species Authority: Raffles, 1822
Common Name(s):
English Black-naped Tern
French Sterne diamant
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.
Taxonomic Notes: 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 entire groups involved.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Ekstrom, J., Butchart, S., Calvert, R.
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 is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to 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.
Previously published Red List assessments:
2009 Least Concern (LC)
2008 Least Concern (LC)
2004 Least Concern (LC)
2000 Lower Risk/least concern (LR/lc)
1994 Lower Risk/least concern (LR/lc)
1988 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description: This species ranges in tropical and subtropical areas of the Indian Ocean and western Pacific Ocean. In the western Indian Ocean it breeds on the Aldabra and Amirante Islands, Seychelles, Chagos Islands (British Indian Ocean Territory) and the Maldives and can be found on the eastern African coast. Its range in the eastern Indian Ocean and Pacific ecompasses the Andaman Islands, India, east to southern Japan and China, south through Indonesia, Malaysia, the Philippenes and New Guinea to north-east Australia and some islands in the western-central Pacific (del Hoyo et al. 1996).

Countries occurrence:
American Samoa (American Samoa); Australia; British Indian Ocean Territory; Brunei Darussalam; Cambodia; China; Comoros; Cook Islands; Fiji; Guam; India; Indonesia; Japan; Kiribati; Malaysia; Maldives; Marshall Islands; Mayotte; Micronesia, Federated States of ; Myanmar; New Caledonia; Northern Mariana Islands; Palau; Papua New Guinea; Philippines; Samoa; Seychelles; Singapore; Solomon Islands; Taiwan, Province of China; Thailand; Timor-Leste; Tonga; Tuvalu; Vanuatu; Viet Nam; Wallis and Futuna
Bangladesh; Madagascar; Sri Lanka
Present - origin uncertain:
Christmas Island; French Southern Territories; Kenya; Mozambique; Nauru; Niue; Somalia; Tanzania, United Republic of; Tokelau; United States Minor Outlying Islands
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 4250000
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The global population size has not been quantified, though national population estimates include: c.100-10,000 breeding pairs and c.50-1,000 individuals on migration in China; c.10,000-100,000 breeding pairs and c.1,000-10,000 individuals on migration in Taiwan and c.100-10,000 breeding pairs and c.50-1,000 individuals on migration in Japan (Brazil 2009).

Trend Justification:  The population trend is difficult to determine because of uncertainty over the extent of threats to the species (del Hoyo et al. 1996).
Current Population Trend: Unknown
Additional data:
Number of mature individuals: Unknown Continuing decline of mature individuals: Unknown
Extreme fluctuations: No Population severely fragmented: No
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Habitat and Ecology: This species frequents small offshore islands, reeds, sand spits and rocky cays, feeding in atoll lagoons and close inshore over breakers, but sometimes also at sea. It feeds mainly on small fish and will almost always forage singly by shallow plunge-diving or surface-diving. Its breeding season varies depending on locality, usually forming small colonies of 5 to 20 pairs, but sometimes up to 200 pairs. Colonies are often monospecific and formed on unlined depression in the sand or in gravel pockets on coral banks close to the high tide line (del Hoyo et al. 1996).

Systems: Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 11
Movement patterns: Full Migrant
Congregatory: Congregatory (and dispersive)

Citation: BirdLife International. 2012. Sterna sumatrana. The IUCN Red List of Threatened Species 2012: e.T22694612A38862845. . Downloaded on 07 October 2015.
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