Onychoprion lunatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Laridae

Scientific Name: Onychoprion lunatus (Peale, 1848)
Common Name(s):
English Grey-backed Tern, Gray-backed Tern, Spectacled Tern
Onychoprion lunatus AOU checklist (1998 + supplements)
Sterna lunata Peale, 1848
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. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
Taxonomic Notes: Onychoprion lunatus (del Hoyo and Collar 2014) was previously placed in the genus Sterna as S. lunata.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Butchart, S., Calvert, R. & Ekstrom, J.
This species has a very 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 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.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The Grey-backed Tern can be found in the tropical Pacific Ocean, from the Hawaiian Islands (USA) and Northern Mariana Islands (to USA) in the north, south through the Phoenix and Line Islands (Kiribati) to Fiji, and east to the Austral and Tuamoto Islands (French Polynesia). It is also found at sea throughout this area (del Hoyo et al. 1996).

Countries occurrence:
American Samoa; Fiji; French Polynesia; Indonesia; Kiribati; Marshall Islands; Micronesia, Federated States of ; Northern Mariana Islands; Palau; Solomon Islands; United States; United States Minor Outlying Islands
Japan; Samoa; Tuvalu
Present - origin uncertain:
Cook Islands; Nauru; Niue; Papua New Guinea; Pitcairn; Tokelau; Tonga; Vanuatu; Wallis and Futuna
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:29100000
Continuing decline in extent of occurrence (EOO):UnknownExtreme 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]

Current Population Trend:Unknown
Additional data:
Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:This species has a diet comprised mainly of fish and squid, but it will also occasionally take lizards. It feeds mainly inshore, often with other terns, and takes tiny fish by plunge-diving, and also by contact-dipping or hover-dipping over schools of tuna. It has a long breeding period of February to September, breeding on oceanic islands on low sea cliffs, sandy beaches or bare found on coral or rocky islands (del Hoyo et al. 1996).

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):12
Movement patterns:Not a Migrant

Citation: BirdLife International. 2016. Onychoprion lunatus. The IUCN Red List of Threatened Species 2016: e.T22694722A93465439. . Downloaded on 24 May 2018.
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