|Red List Category & Criteria:
||Butchart, S. & Symes, A.
||Butchart, S., Calvert, R. & Ekstrom, J.
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:|
- 2012 – Least Concern (LC)
- 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)
|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). |
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:||61800000|
|♦ 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:||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|
|♦ 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|