Caspian Tern Hydroprogne caspia


Taxonomic note
Hydroprogne caspia (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: # _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: #
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 full migrant Forest dependency does not normally occur in forest
Land-mass type Average mass -

Estimate Data quality
Extent of Occurrence (breeding/resident) 226,000,000 km2 medium
Extent of Occurrence (non-breeding) 187,000,000 km2 medium
Severely fragmented? no -
Estimate Data quality Derivation Year of estimate
Population size unknown poor estimated 2012
Population trend increasing - suspected -
Generation length 12.2 years - - -

Population justification: The global population is estimated to number c.250,000-470,000 individuals (Wetlands International 2015). The European population is estimated at 11,800-14,800 pairs, which equates to 23,600-29,600 mature individuals (BirdLife International 2015). National population estimates include: c.50-1,000 individuals on migration and c.50-1,000 wintering individuals in China; c.50-1,000 individuals on migration and c.50-1,000 wintering individuals in Taiwan; < c.50 individuals on migration and < c.50 wintering individuals in Japan and c.100-10,000 breeding pairs and c.50-1,000 individuals on migration in Russia (Brazil 2009).

Trend justification: The overall population trend is increasing, although some populations are decreasing, stable, or have unknown trends (Delany & Scott 2006). This species has undergone a large and statistically significant increase over the last 40 years in North America (266% increase over 40 years, equating to a 38.3% increase per decade; data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007). The European population trend is estimated to be increasing (BirdLife International 2015).

Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Afghanistan extant native yes
Albania extant native yes
Algeria extant native
Angola extant native
Anguilla (to UK) extant vagrant
Antigua and Barbuda extant vagrant
Aruba (to Netherlands) extant native
Australia extant native yes
Austria extant native yes
Azerbaijan extant native yes yes
Bahamas extant native
Bahrain extant native yes yes
Bangladesh extant native
Barbados extant native
Belarus extant native yes
Belgium extant vagrant
Belize extant native yes
Benin extant native yes
Bermuda (to UK) extant vagrant
Botswana extant native
Brunei extant native
Bulgaria extant native
Burkina Faso extant native
Burundi extant vagrant
Cambodia extant native
Cameroon extant native
Canada extant native yes
Cayman Islands (to UK) extant native
Central African Republic extant native
Chad extant native
China (mainland) extant native
Colombia extant native
Comoros extant native
Congo extant native
Congo, The Democratic Republic of the extant vagrant
Costa Rica extant native yes
Côte d'Ivoire extant native
Croatia extant vagrant
Cuba extant native
Cyprus extant native
Czechia extant native
Denmark extinct native yes
Djibouti extant native
Dominica extant vagrant
Dominican Republic extant native
Ecuador extant vagrant
Egypt extant native yes
El Salvador extant native yes
Equatorial Guinea extant native
Eritrea extant native
Estonia extant native yes
Eswatini extant vagrant
Ethiopia extant native
Faroe Islands (to Denmark) extant vagrant
Finland extant native yes yes
France extant native yes
French Guiana extant native
Gabon extant native
Gambia extant native yes
Germany extant native yes yes
Ghana extant native
Gibraltar (to UK) extant vagrant
Greece extant native yes yes
Guadeloupe (to France) extant vagrant yes
Guatemala extant native
Guinea extant native yes
Guinea-Bissau extant native yes
Haiti extant native
Honduras extant native
Hong Kong (China) extant native
Hungary extant native
India extant native
Indonesia extant native
Iran, Islamic Republic of extant native yes yes
Iraq extant native yes yes
Ireland extant vagrant
Israel extant native
Italy extant native
Jamaica extant native
Japan extant native
Jordan extant native yes
Kazakhstan extant native yes
Kenya extant native
Kuwait extant native yes yes
Kyrgyzstan extant vagrant
Laos extant native
Latvia extant native yes
Liberia extant native
Libya extant native
Lithuania extant native yes
Luxembourg extant vagrant
Madagascar extant native
Malaysia extant native
Maldives extant native
Mali extant native
Malta extant native
Martinique (to France) extant vagrant
Mauritania extant native yes
Mayotte (to France) extant native
Mexico extant native
Moldova extant native yes
Mongolia extant native yes
Montenegro extant vagrant
Morocco extant native
Mozambique extant native
Myanmar extant native
Namibia extant native yes
Nepal extant native
Netherlands extant native
New Zealand extant native yes
Nicaragua extant native
Niger extant native
Nigeria extant native
North Macedonia extant native yes
Norway extant vagrant
Oman extant native yes yes
Pakistan extant native
Palestine extant native yes
Panama extant native
Philippines extant native
Poland extant native yes yes
Portugal extant native yes
Puerto Rico (to USA) extant native
Qatar extant native yes
Romania extant native
Russia extant native yes yes
Russia (Asian) extant native yes
Russia (Central Asian) extant native yes
Russia (European) extant native yes yes
Rwanda extant vagrant
Saudi Arabia extant native yes yes
Senegal extant native yes
Serbia extant vagrant
Seychelles extant native
Sierra Leone extant native
Singapore extant native
Slovakia extant native yes
Slovenia extant vagrant
Somalia extant native
South Africa extant native yes
South Sudan extant native yes yes
Spain extant native yes
Sri Lanka extant native
St Kitts and Nevis extant vagrant
St Lucia extant vagrant
St Pierre and Miquelon (to France) extant native yes yes
Sudan extant native
Sweden extant native yes yes
Switzerland extant native
Syria 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
Tunisia extant native
Türkiye extant native yes
Turkmenistan extant native yes
Turks and Caicos Islands (to UK) extant native
Uganda extant native
Ukraine extant native yes
United Arab Emirates extant native yes yes
United Kingdom extant vagrant
USA extant native yes
Uzbekistan extant native yes
Venezuela extant native
Vietnam extant native yes
Virgin Islands (to USA) extant vagrant
Western Sahara extant native
Yemen extant native yes yes
Zambia extant native
Zimbabwe extant native

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Türkiye Büyük Menderes Delta
Sweden Coastal area of Eastern Gotland
Sweden Rödkallen – Söräspen Islands
Sweden Lake Storhjälmaren
Sweden Archipelago of Stockholm
Sweden Gräsö Archipelago
Sweden Holmöarna Archipelago
Greece Mesolongi and Aitoliko lagoons, Acheloos delta and Evinos estuary
Greece Lake Amvrakia
Finland Eckerö and Hammarland archipelago
Finland Oura and Enskeri archipelagos
Finland Pori archipelago and wetlands
Finland Tammisaari and Inkoo western archipelago
Finland Porvoo outer archipelago
Finland Pernaja outer archipelago
Finland Kirkon-Vilkkiläntura Bay
Finland Itäinen Suomenlahti National Park
Finland Kristiinankaupunki southern archipelago
Finland Merenkurkku archipelago
Finland Kokkola and Kälviä archipelago
Finland Oulu region wetlands
Finland Krunnit archipelago
Ukraine Syvash Bay
Ukraine Karkinits'ka and Dzharylgats'ka bays
France Camargue
Sweden Coastal area (including seaside meadows) of Eastern Öland
Germany Danube valley: Neu-Ulm - Lauingen incl. Faiminger Stausee, Donau-Moos, and Gundelfinger Moos
Germany Vogelfreistätte Mittlere Isar-Stauseen
Germany Wagbach lowlands
Egypt Hurghada archipelago
Ghana Keta Lagoon Ramsar Site
Gambia Niumi National Park
Gambia Tanbi wetland complex
Gambia Tanji River (Karinti) Bird Reserve
Gambia Allahein to Kartung coast
Guinea Iles Tristao
Kenya Tana River Delta
Morocco Baie d'Ad Dakhla
Mali Lac Horo
Mali Lac Débo - Lac Oualado Débo
Mauritania Cap Blanc
Mauritania Lac d'Aleg
Namibia Walvis Bay
Namibia Sandwich Harbour
South Africa Berg River Estuary
Iran, Islamic Republic of Bahu Kalat (Gandu) Protected Area
Oman Barr al Hikman
Oman Masirah island
Oman Duqm
Oman Khawr Ghawi
Saudi Arabia Tarut Bay
Saudi Arabia Jiddah south corniche and port
Yemen Aden
Yemen Bahr Ibn Abbas - Ra's Isa
Russia (European) Valaamski archipelago
Russia (European) Khanskoye Lake
Russia (European) Dolgy Reef and Bol'shoi Fiskar archipelagos
Russia (European) Mouth of Samur river
Taiwan, China Budai Wetlands
Mongolia Khar Us Lake
Mongolia Khar Lake
Estonia Irbe strait
Estonia Kahtla-Kübassaare
Estonia Väinameri
Russia (Central Asian) Chanovskaya lake system
Russia (European) Kiziltash limans
Russia (European) Yeiski salt-lakes
Canada Little George Island
Canada Lake St. Martin Islands
Canada Sand Reef Islands
Canada Spruce Island Reef
Canada Presqu'ile Provincial Park
Canada The Watchers
Canada Pigeon Island
Sweden Ledskär – Bay of Karlholm
Sweden Lövsta Bight – Björn Archipelago
Sweden Coastal area of Oskarshamn
Sweden Bay of Brå – Hävringe Island
Sweden Bay of Strandstugu
Sweden Archipelago of Östergötland
Russia (European) Delta of the Kuban' river
Türkiye Tuz Lake
Türkiye Gediz Delta
Australia Paroo Floodplain and Currawinya
Türkiye Keban Islands
Türkiye South Keban Dam
Australia Lake Eyre
Australia Strzelecki Desert Lakes
Germany Greifswalder Bodden
Germany Coast and lagoons of Western Pomerania
Romania Danube Delta
Romania Black Sea
Lithuania Nemunas delta regional Park
Senegal Parc National de la Langue de Barbarie - marine
USA East Sand Island
Yemen Islands north of Al-Hudaydah
Senegal Delta du Saloum - marine
Gambia Delta du Saloum – Niumi – Tanbi
Guinea-Bissau Arquipélago dos Bijagós - marine
Netherlands Haringvliet
Netherlands Lake IJsselmeer
Netherlands Ketelmeer & Vossemeer
Netherlands Lauwersmeer
United Arab Emirates Al Zorah (Khor Ajman)
Russia (European) Delta of the River Don
Russia (European) Islands in the western part of Lake Manych-Gudilo
Guinea-Bissau Rio Cacheu
Guinea-Bissau Rio Mansôa and Gêba estuary
Guinea-Bissau Arquipélago dos Bijagós
Senegal La Petite Côte
Senegal Delta du Saloum
Senegal Parc National de Basse Casamance
Senegal Kalissaye Avifaunal Reserve
Mauritania Banc d'Arguin National Park
Mauritania Aftout es Sâheli
Mauritania Diawling National Park
Mexico Cuitzeo
South Africa iSimangaliso Wetland Park

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Aquatic & Marine Artificial/Aquatic - Water Storage Areas (over 8ha) suitable breeding
Artificial/Aquatic & Marine Artificial/Aquatic - Water Storage Areas (over 8ha) suitable non-breeding
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes suitable breeding
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes suitable non-breeding
Marine Coastal/Supratidal Coastal Freshwater Lakes suitable breeding
Marine Coastal/Supratidal Coastal Freshwater Lakes suitable non-breeding
Marine Intertidal Salt Marshes (Emergent Grasses) suitable breeding
Marine Intertidal Salt Marshes (Emergent Grasses) suitable non-breeding
Marine Neritic Estuaries suitable breeding
Marine Neritic Estuaries suitable non-breeding
Marine Neritic Macroalgal/Kelp suitable breeding
Marine Neritic Macroalgal/Kelp suitable non-breeding
Marine Neritic Pelagic suitable breeding
Marine Neritic Pelagic suitable non-breeding
Marine Neritic Seagrass (Submerged) suitable breeding
Marine Neritic Seagrass (Submerged) suitable non-breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel suitable breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel suitable non-breeding
Marine Neritic Subtidal Rock and Rocky Reefs suitable breeding
Marine Neritic Subtidal Rock and Rocky Reefs suitable non-breeding
Marine Neritic Subtidal Sandy suitable breeding
Marine Neritic Subtidal Sandy suitable non-breeding
Marine Neritic Subtidal Sandy-Mud suitable breeding
Marine Neritic Subtidal Sandy-Mud suitable non-breeding
Wetlands (inland) Bogs, Marshes, Swamps, Fens, Peatlands major breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) suitable breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) suitable non-breeding
Wetlands (inland) Seasonal/Intermittent Freshwater Lakes (over 8ha) suitable breeding
Wetlands (inland) Seasonal/Intermittent Freshwater Lakes (over 8ha) suitable non-breeding
Altitude   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
Reduced reproductive success, Species mortality
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Species disturbance, Reduced reproductive success

Purpose Primary form used Life stage used Source Scale Level Timing
Pets/display animals, horticulture - - international non-trivial recent
Sport hunting/specimen collecting - - non-trivial recent

Recommended citation
BirdLife International (2024) Species factsheet: Hydroprogne caspia. Downloaded from on 24/02/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from on 24/02/2024.