Data Zone
Taxonomic note
Onychoprion lunatus (del Hoyo and Collar 2014) was previously placed in the genus Sterna as S. lunata.
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.
| Critically Endangered | Endangered | Vulnerable |
|---|---|---|
| - | - | - |
| Year | Category | Criteria |
|---|---|---|
| 2018 | Least Concern | |
| 2016 | Least Concern | |
| 2012 | Least Concern | |
| 2009 | Least Concern | |
| 2008 | Least Concern | |
| 2004 | Least Concern | |
| 2000 | Lower Risk/Least Concern | |
| 1994 | Lower Risk/Least Concern | |
| 1988 | Lower Risk/Least Concern |
| Migratory status | not a migrant | Forest dependency | does not normally occur in forest |
| Land-mass type | Average mass | - |
| Estimate | Data quality | |
|---|---|---|
| Extent of Occurrence (breeding/resident) | 29,100,000 km2 | |
| Extent of Occurrence (non-breeding) | 45,900,000 km2 | |
| Severely fragmented? | no | - |
| Estimate | Data quality | Derivation | Year of estimate | |
|---|---|---|---|---|
| Population size | unknown | poor | estimated | 2009 |
| Population trend | decreasing | - | suspected | - |
| Generation length | 12 years | - | - | - |
Population justification: The population is estimated at 100,000-1,000,000 individuals.
Trend justification: The population is suspected to be in decline owing to predation at breeding sites (del Hoyo et al. 1996).
| Country/Territory | Presence | Origin | Resident | Breeding visitor | Non-breeding visitor | Passage migrant |
|---|---|---|---|---|---|---|
| American Samoa | extant | native | yes | |||
| Cook Islands | extant | uncertain | ||||
| Fiji | extant | native | yes | |||
| French Polynesia | extant | native | yes | |||
| Indonesia | extant | native | yes | |||
| Japan | extant | vagrant | yes | |||
| Kiribati | extant | native | yes | |||
| Marshall Islands | extant | native | yes | |||
| Micronesia, Federated States of | extant | native | yes | |||
| Nauru | extant | uncertain | ||||
| Niue (to New Zealand) | extant | uncertain | ||||
| Northern Mariana Islands (to USA) | extant | native | yes | |||
| Palau | extant | native | yes | |||
| Papua New Guinea | extant | uncertain | ||||
| Pitcairn Islands (to UK) | extant | uncertain | ||||
| Samoa | extant | vagrant | yes | |||
| Solomon Islands | extant | native | yes | |||
| Tokelau (to New Zealand) | extant | uncertain | ||||
| Tonga | extant | uncertain | ||||
| Tuvalu | extant | vagrant | yes | |||
| United States Minor Outlying Islands (to USA) | extant | native | yes | |||
| USA | extant | native | yes | |||
| Vanuatu | extant | uncertain | ||||
| Wallis and Futuna Islands (to France) | extant | uncertain |
| Country/Territory | IBA Name |
|---|---|
| Kiribati | Abariranga (Canton) Island |
| Kiribati | Phoenix Islands Marine |
| Kiribati | Rawaki (Phoenix Island) |
| Northern Mariana Islands (to USA) | Guguan Island |
| Northern Mariana Islands (to USA) | Guguan Island Marine |
| USA | Northwestern Hawaiian Islands |
| Habitat (level 1) | Habitat (level 2) | Importance | Occurrence |
|---|---|---|---|
| Marine Coastal/Supratidal | Sea Cliffs and Rocky Offshore Islands | major | breeding |
| Marine Intertidal | Rocky Shoreline | major | breeding |
| Marine Intertidal | Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc | major | breeding |
| Marine Intertidal | Shingle and/or Pebble Shoreline and/or Beaches | major | breeding |
| Marine Intertidal | Tidepools | major | breeding |
| Marine Neritic | Macroalgal/Kelp | suitable | resident |
| Marine Neritic | Pelagic | major | non-breeding |
| Marine Neritic | Seagrass (Submerged) | suitable | resident |
| Marine Neritic | Subtidal Loose Rock/pebble/gravel | suitable | resident |
| Marine Neritic | Subtidal Rock and Rocky Reefs | suitable | resident |
| Marine Neritic | Subtidal Sandy | suitable | resident |
| Marine Neritic | Subtidal Sandy-Mud | suitable | resident |
| Rocky areas (eg. inland cliffs, mountain peaks) | suitable | breeding | |
| Altitude | Occasional altitudinal limits |
| Threat (level 1) | Threat (level 2) | Impact and Stresses | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Named species | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Rapid Declines | Medium Impact: 6 | ||||||
|
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Recommended citation
BirdLife International (2024) Species factsheet: Grey-backed Tern Onychoprion lunatus. Downloaded from
https://datazone.birdlife.org/species/factsheet/grey-backed-tern-onychoprion-lunatus on 27/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 27/11/2024.