LC
Bridled Tern Onychoprion anaethetus



Taxonomy

Taxonomic note
Onychoprion anaethetus (del Hoyo and Collar 2014) was previously placed in the genus Sterna.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: http://www.aerc.eu/DOCS/Bird_taxa_of_the_WP15.xls.
Christidis, L. and Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. CSIRO Publishing, Collingwood, Australia.
Cramp, S. and Simmons, K.E.L. (eds). 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
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.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm.
Turbott, E.G. 1990. Checklist of the Birds of New Zealand. Ornithological Society of New Zealand, Wellington.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2019 Least Concern
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
Species attributes

Migratory status full migrant Forest dependency does not normally occur in forest
Land-mass type Average mass -
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 207,000,000 km2 medium
Extent of Occurrence (non-breeding) 222,000,000 km2 medium
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 400000-1000000 mature individuals poor estimated 2006
Population trend unknown - - -
Generation length 11.3 years - - -

Population justification: The global population is estimated to number 610,000-1,500,000 individuals (Delany and Scott 2006). This roughly equates to 400,000-1,000,000 mature individuals. National population estimates include 100-10,000 breeding pairs and 50-1,000 individuals on migration in China; 10,000-1 million breeding pairs and > 1,000 individuals on migration in Taiwan (China) and < 100 breeding pairs and < 50 individuals on migration in Japan (Brazil 2009).

Trend justification: The overall population trend is uncertain, as some populations are decreasing, while others are increasing or have unknown trends (Delany and Scott 2006).


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Anguilla (to UK) extant native yes
Antigua and Barbuda extant native
Aruba (to Netherlands) extant native
Australia extant native yes
Bahamas extant native
Bahrain extant native yes
Barbados extant native
Belize extant native
Benin extant uncertain
Bermuda (to UK) extant native yes
Bonaire, Sint Eustatius and Saba (to Netherlands) extant native
Brunei extant native
Cambodia extant native
Canada extant native
Cayman Islands (to UK) extant native
Chile extant vagrant
China (mainland) extant native yes
Christmas Island (to Australia) extant uncertain
Cocos (Keeling) Islands (to Australia) extant vagrant
Colombia extant native
Comoros extant native
Costa Rica extant native yes
Cuba extant native
Curaçao (to Netherlands) extant native
Denmark extant vagrant
Djibouti extant native
Dominica extant native
Dominican Republic extant native
Ecuador extant native yes
Egypt extant native
El Salvador extant native
Equatorial Guinea extant native
Eritrea extant native
Fiji extant native yes
French Southern Territories extant uncertain
Gambia extant uncertain
Ghana extant vagrant
Greece extant vagrant
Grenada extant native
Guadeloupe (to France) extant native yes
Guatemala extant uncertain
Guinea extant uncertain
Guinea-Bissau extant native
Guyana extant native
Haiti extant native
Honduras extant native
India extant native
Indonesia extant native
Iran, Islamic Republic of extant native yes
Iraq extant native yes
Israel extant native
Jamaica extant native yes
Japan extant native
Jordan extant native yes
Kenya extant native
Kuwait extant native yes
Liberia extant vagrant
Madagascar extant native
Malaysia extant native
Maldives extant native yes
Martinique (to France) extant native
Mauritania extant native
Mauritius extant native yes
Mayotte (to France) extant uncertain
Mexico extant native
Montserrat (to UK) extant native
Mozambique extant native
Myanmar extant uncertain
New Caledonia (to France) extant native
New Zealand extant vagrant
Nicaragua extant native
Nigeria extant native
Oman extant native yes
Pakistan extant native
Palau extant native yes
Panama extant native
Papua New Guinea extant native
Philippines extant native
Puerto Rico (to USA) extant native
Qatar extant native yes
Réunion (to France) extant uncertain
São Tomé e Príncipe extant native
Saudi Arabia extant native yes
Senegal extant native
Seychelles extant native
Sierra Leone extant uncertain
Singapore extant native
Sint Maarten (to Netherlands) extant native yes
Solomon Islands extant native
Somalia extant native yes
South Africa extant native
Sri Lanka extant native
St Barthelemy (to France) extant native
St Kitts and Nevis extant native
St Lucia extant native
St Martin (to France) extant native yes
St Vincent and the Grenadines extant native
Sudan extant native yes
Taiwan, China extant native yes
Tanzania extant native
Thailand extant native
Timor-Leste extant native yes
Togo extant native
Trinidad and Tobago extant native
Turks and Caicos Islands (to UK) extant native yes
United Arab Emirates extant native yes yes
United Kingdom extant vagrant
USA extant native yes
Vanuatu extant vagrant
Venezuela extant native
Vietnam extant native
Virgin Islands (to UK) extant native yes
Virgin Islands (to USA) extant native yes
Wallis and Futuna Islands (to France) extant native yes
Western Sahara extant native yes
Yemen extant native yes yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Anguilla (to UK) Dog Island
Anguilla (to UK) Sombrero Island
Aruba (to Netherlands) San Nicolas Bay Reef Islands
Australia Cape York to Cape Grenville Islands
Australia Higginson Island
Australia Houtman Abrolhos
Australia Lowendal Islands
Australia South Barnard Islands
Australia Stapleton Island
Australia Three Hummocks Island
Bahamas Booby Island
Bahamas Cay Lobos
Bahamas Cay Sal
Bahamas Conception Island National Park
Bahamas Goulding Cay Wild Bird Reserve
Bahamas Great Isaac Cay
Bahamas Guana Cays
Bahamas Low Cay, High Cay and Sandy Hook
Bahamas North Atlantic Abaco Cays
Bahamas Peterson Cay (National Park)
Bahamas Samana Cay
Bahamas Tee Cay, Goat Cay and Long Rocks
China (mainland) Beiji Islands
China (mainland) Dongtou Islands
China (mainland) Nanji Islands Nature Reserve
China (mainland) Taizhou Islands
China (mainland) Wuyu Dao Island
China (mainland) Yushan Islands
China (mainland) Zhongjieshan Islands
Cuba Gran Humedal del Norte de Ciego de Ávila
Dominica L'llet
Dominica Point Des Foux
Dominican Republic Siete Hermanos Keys
Guadeloupe (to France) Falaises Nord et Îlet de Vieux-Fort de Marie-Galante
Guadeloupe (to France) Pointe des Châteaux
Indonesia Pulau Gunung Api
Indonesia Pulau Manuk
Iran, Islamic Republic of Nakhilu, Morghu and Ummal Karam islands
Iran, Islamic Republic of Sheedvar island
Jamaica Morant Cays and Bank
Jamaica Pedro Cays and Bank
Japan Yaeyama islands
Japan Yaeyama islands - Marine
Martinique (to France) Îlets et falaises de Sainte Anne
Martinique (to France) Rocher du Diamant
Mexico Islas Marietas
Mexico Morros de Potosí
Nicaragua Farallones de Cosiguina
Nicaragua Farallones de Cosiguina - Marine
Oman Barr al Hikman
Oman Daymaniyat Islands
Oman Halaaniyaat Islands
Oman Masirah island
Oman Musandam islands
Panama Frailes del Sur Islands
Saudi Arabia Farasan Islands
Saudi Arabia Gulf coral islands
Saudi Arabia Gulf of Salwah
Saudi Arabia Tarut Bay
Somalia Jasiira Ceebaad and Jasiira Sacaada Diin
St Kitts and Nevis Booby Island
St Lucia Point Sables
Taiwan, China Cat Islet Seabird Refuge, Penghu County Refuge
Taiwan, China Matsu (Mazu) Islands Tern Refuge
Taiwan, China Northern Sea Islets
Trinidad and Tobago Little Tobago Island
Turks and Caicos Islands (to UK) Caicos Bank Southern Cays
Turks and Caicos Islands (to UK) Turks Bank Seabird Cays
United Arab Emirates Dayyinah Island (Diynah)
United Arab Emirates Qarnain Island
United Arab Emirates Sir Bu Na'air Island
United Arab Emirates Umm Amim
USA Dry Tortugas National Park
Virgin Islands (to USA) Saba Island and Cays
Yemen Islands north of Al-Hudaydah
Yemen Jaza'ir al-Hanish

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Sea Cliffs and Rocky Offshore Islands suitable breeding
Marine Intertidal Rocky Shoreline suitable 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 suitable breeding
Marine Neritic Macroalgal/Kelp major breeding
Marine Neritic Macroalgal/Kelp major non-breeding
Marine Neritic Pelagic major breeding
Marine Neritic Pelagic major non-breeding
Marine Neritic Seagrass (Submerged) major breeding
Marine Neritic Seagrass (Submerged) major non-breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel major breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel major non-breeding
Marine Neritic Subtidal Rock and Rocky Reefs major breeding
Marine Neritic Subtidal Rock and Rocky Reefs major non-breeding
Marine Neritic Subtidal Sandy major breeding
Marine Neritic Subtidal Sandy major non-breeding
Marine Neritic Subtidal Sandy-Mud major breeding
Marine Neritic Subtidal Sandy-Mud major non-breeding
Marine Oceanic Epipelagic (0-200m) suitable breeding
Marine Oceanic Epipelagic (0-200m) suitable non-breeding
Marine Oceanic Mesopelagic (200-1000m) suitable breeding
Marine Oceanic Mesopelagic (200-1000m) suitable non-breeding
Altitude 0 - 50 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Reduced reproductive success, Species mortality
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species disturbance

Utilisation
Purpose Scale
Pets/display animals, horticulture international

Recommended citation
BirdLife International (2024) Species factsheet: Bridled Tern Onychoprion anaethetus. Downloaded from https://datazone.birdlife.org/species/factsheet/bridled-tern-onychoprion-anaethetus on 23/12/2024.
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 23/12/2024.