LC
Common White Tern Gygis alba



Taxonomy

Taxonomic source(s)
Christidis, L. and Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. CSIRO Publishing, Collingwood, Australia.
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: #http://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
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 not a migrant Forest dependency Does not normally occur in forest
Land mass type Average mass -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 137,000,000
Extent of Occurrence non-breeding (km2) 150,000,000
Number of locations -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals poor estimated 2006
Population trend Stable suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Largest subpopulations - - -
Generation length (yrs) 15.3 - - -

Population justification: Delany and Scott (2006) estimate the population at 150000-1100000 individuals.

Trend justification: The overall population trend is stable, although some populations have unknown trends (Delany and Scott 2006).


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
American Samoa N Extant Yes
Australia N Extant Yes
Bangladesh N Extant Yes
Bermuda (to UK) V Extant Yes
Brazil N Extant Yes
British Indian Ocean Territory N Extant Yes
Chile N Extant Yes
China (mainland) N Extant Yes
Christmas Island (to Australia) V Extant Yes
Cocos (Keeling) Islands (to Australia) N Extant Yes
Colombia N Extant Yes
Comoros N Extant Yes
Cook Islands N Extant Yes
Costa Rica N Extant Yes
Fiji N Extant Yes
French Polynesia N Extant Yes
French Southern Territories U Extant
Guam (to USA) N Extant Yes
India N Extant Yes
Indonesia N Extant Yes
Japan N Extant Yes
Kiribati N Extant Yes
Madagascar U Extant
Maldives N Extant Yes
Marshall Islands N Extant Yes
Mauritius N Extant Yes
Mayotte (to France) N Extant Yes
Mexico N Extant Yes
Micronesia, Federated States of N Extant Yes
Nauru N Extant Yes
New Caledonia (to France) N Extant Yes
New Zealand N Extant Yes
Niue (to New Zealand) N Extant Yes
Norfolk Island (to Australia) N Extant Yes
Northern Mariana Islands (to USA) N Extant Yes
Palau N Extant Yes
Panama V Extant Yes
Papua New Guinea N Extant Yes
Philippines U Extant
Pitcairn Islands (to UK) N Extant Yes
Réunion (to France) N Extant Yes
Samoa N Extant Yes
Seychelles N Extant Yes
Solomon Islands N Extant Yes
St Helena (to UK) N Extant Yes
Timor-Leste U Extant
Tokelau (to New Zealand) N Extant Yes
Tonga N Extant Yes
Trinidad and Tobago N Extant Yes
Tuvalu N Extant Yes
United States Minor Outlying Islands (to USA) N Extant Yes
USA N Extant Yes
Vanuatu N Extant Yes
Vietnam N Extant Yes
Wallis and Futuna Islands (to France) N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
American Samoa Rose Atoll
French Polynesia Manuae, Motu One et Maupihaa
French Polynesia Fangataufa
Marshall Islands Bokak Atoll
Mauritius Cargados Carajos Shoals
Seychelles Aride Island Special Reserve
Seychelles Cousin Island Special Reserve
Seychelles Cousine island
Seychelles Frégate island
Seychelles Marie-Louise Island
Pitcairn Islands (to UK) Ducie Island
Pitcairn Islands (to UK) Henderson Island
Brazil Trindade e Martim Vaz
French Polynesia Manui, Kamaka, Makaroa
Palau Fana Island
French Polynesia Tetiaroa
French Polynesia Morane
French Polynesia Niau
French Polynesia Anuanuraro
French Polynesia Reitoru
French Polynesia Motane (Mohotani)
Marshall Islands Taongi Atoll
Tonga Maninita, Taula, Lualoli
Marshall Islands Taka Atoll
Marshall Islands Enewetok Atoll
Northern Mariana Islands (to USA) Tinian Island
Kiribati McKean Island
Kiribati Orona Atoll (Hull Island)
Kiribati Nikumaroro (Gardner Island)
Kiribati Abariranga (Canton) Island
Kiribati Enderbury Island
Kiribati Rawaki (Phoenix Island)
Kiribati Teraina (Washington Island)
Kiribati Tabuaeran (Fanning Island)
Kiribati Kiritimati (Christmas Island)
Kiribati Malden Island
Kiribati Vostok Island
Kiribati Millenium (Caroline) Island
Fiji Vetauua
Micronesia, Federated States of Yap Island
French Polynesia Motu de l'ouest et du sud de Rangiroa
American Samoa West Tutuila
American Samoa National Park of American Samoa - Ta'u
American Samoa National Park of American Samoa - Tutuila
American Samoa Swain's Atoll
French Polynesia Tahanea
French Polynesia Rimatara
French Polynesia Vallée de Avera
French Polynesia Makatea
French Polynesia Ilots rocheux de Rapa et Marotiri
French Polynesia Moruroa
French Polynesia Kauehi
French Polynesia Tikehau
USA Northwestern Hawaiian Islands
French Polynesia Rapa
French Polynesia Hatuta'a
French Polynesia Tubuai, Motu Toena
French Polynesia Agakauitai
French Polynesia Akamaru island
French Polynesia Mangareva
French Polynesia Motu Teiku
French Polynesia Hiva Oa
French Polynesia Bora Bora
French Polynesia Huahine
French Polynesia Maiao
French Polynesia Maupiti
French Polynesia Mehetia
French Polynesia Moorea
French Polynesia Tupai
French Polynesia Anuanurunga
French Polynesia Fakarava Atolls
French Polynesia Haraiki
French Polynesia Hereheretue
French Polynesia Manuhangi
French Polynesia Motutunga
French Polynesia Nukutepipi
French Polynesia Tekokota
New Zealand Kermadec Islands (Raoul Island) - Western Bay, Denham Bay, Islets
French Polynesia Hatu iti
Palau Ngeriungs, Palau
Palau Rock Islands
Palau Helen Island, Hatohobei
Palau Peleliu
Brazil Trindade e Martim Vaz - Marine
Mauritius Cargados Carajos shoals (Saint Brandon) - Marine
Seychelles African Banks / Boudeuse island / Etoile island / Marie Louise island - Marine
Seychelles Aride island - Marine
Norfolk Island (to Australia) Norfolk Island / Phillip Island - Marine
Brazil Arquipélago de Fernando de Noronha
Micronesia, Federated States of Gaferut (Faiyew) Island
Micronesia, Federated States of Chuuk Atoll Marine
Micronesia, Federated States of East Fayu
Micronesia, Federated States of Wolouna, Ahnd Atoll
Micronesia, Federated States of Pohnpei Marine
Micronesia, Federated States of Kosrae Marine
Marshall Islands Bikar Atoll
United States Minor Outlying Islands (to USA) Wake Island
Fiji Nukubasaga & Nukupureti
United States Minor Outlying Islands (to USA) Baker Island
United States Minor Outlying Islands (to USA) Howland Island
United States Minor Outlying Islands (to USA) Johnston Atoll
United States Minor Outlying Islands (to USA) Palmyra Atoll
United States Minor Outlying Islands (to USA) Jarvis Island
Cook Islands Suwarrow Atoll National Park
Cook Islands Takutea Wildlife Sanctuary
Cook Islands Aitutaki
Cook Islands Atiu
Cook Islands Mangaia
Cook Islands Ma'uke Island
Cook Islands Rarotonga Cloud Forest
Cook Islands Takitumu Conservation Area, Rarotonga
Micronesia, Federated States of Polle Island
Micronesia, Federated States of Pata Island
Micronesia, Federated States of Yap Island Marine
Fiji Ringgold Islands Marine
Palau Fana Island Marine
French Polynesia Rangiroa Marine
Kiribati Flint Island
New Caledonia (to France) Île Walpole
New Caledonia (to France) Île Hunter
Tonga Niuafo'ou
Tonga Late
Tonga 'Ata Island
Tokelau (to New Zealand) Atafu
Tokelau (to New Zealand) Nukunonu
Northern Mariana Islands (to USA) Uracus
Northern Mariana Islands (to USA) Maug Islands
Northern Mariana Islands (to USA) Guguan Island
Papua New Guinea Tench Island
French Polynesia Clipperton
Wallis and Futuna Islands (to France) Futuna
Wallis and Futuna Islands (to France) Alofi
American Samoa Tutuila Marine
French Polynesia Tikehau Marine
Kiribati Teraina Marine
Tokelau (to New Zealand) Tokelau Marine
Wallis and Futuna Islands (to France) Futuna Marine
American Samoa Swain's Atoll Marine
French Polynesia Niau Marine
French Polynesia Moruroa Marine
Kiribati Millenium (Caroline) Island Marine
Fiji Ringgold Islands
St Helena (to UK) Boatswainbird Island
St Helena (to UK) Green Mountain

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Sea Cliffs and Rocky Offshore Islands suitable breeding
Marine Neritic Coral Reef - Back Slope major breeding
Marine Neritic Coral Reef - Foreslope (Outer Reef Slope) major breeding
Marine Neritic Coral Reef - Inter-Reef Rubble Substrate major breeding
Marine Neritic Coral Reef - Inter-Reef Soft Substrate major breeding
Marine Neritic Coral Reef - Lagoon major breeding
Marine Neritic Coral Reef - Outer Reef Channel major breeding
Marine Neritic Macroalgal/Kelp major resident
Marine Neritic Pelagic major resident
Marine Neritic Seagrass (Submerged) major resident
Marine Neritic Subtidal Loose Rock/pebble/gravel major resident
Marine Neritic Subtidal Rock and Rocky Reefs major resident
Marine Neritic Subtidal Sandy major resident
Marine Neritic Subtidal Sandy-Mud major resident
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%) Slow, Significant Declines Low Impact: 5
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Felis catus Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Reduced reproductive success

Recommended citation
BirdLife International (2020) Species factsheet: Gygis alba. Downloaded from http://www.birdlife.org on 06/04/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/04/2020.