email a friend
printable version
Royal Tern Thalasseus maximus
BirdLife is updating this factsheet for the 2016 Red List
Please email us with any relevant information

IUCN Red List history

Year Category
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 (km2) 983,000 medium
Extent of Occurrence non-breeding (km2) 1,910,000 medium
Number of locations -
Fragmentation -

Population & trend

  Estimate Data quality Derivation Year of estimate
No. of mature individuals poor Estimated 2009
Population trend Stable -
Number of subpopulations - - -
Largest subpopulation - - -
Generation length (yrs) 11.2 - - -
Trend justification: The overall population trend is stable, although some populations have unknown trends (Wetlands International 2006). This species has undergone a small or statistically insignificant increase over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007) Note, however, that these surveys cover less than 50% of the species's range in North America.

Country/Territory distribution

Country/Territory Occurrence status Presence Breeding Non-breeding Passage Resident
Angola Native Extant        
Anguilla (to UK) Native Extant        
Antigua and Barbuda Native Extant        
Argentina Native Extant        
Aruba (to Netherlands) Native Extant        
Bahamas Native Extant        
Barbados Native Extant        
Belize Vagrant Extant        
Benin Native Extant        
Bermuda (to UK) Native Extant        
Bonaire, Sint Eustatius and Saba (to Netherlands) Native Extant        
Brazil Native Extant        
Cameroon Native Extant        
Canada Native Extant        
Cayman Islands (to UK) Native Extant        
Chile Unknown Extant        
Colombia Native Extant        
Congo Native Extant        
Congo, The Democratic Republic of the Native Extant        
Costa Rica Native Extant   Yes    
Côte d'Ivoire Native Extant        
Cuba Native Extant        
Curaçao (to Netherlands) Native Extant        
Dominica Native Extant        
Dominican Republic Native Extant        
Ecuador Native Extant   Yes    
El Salvador Native Extant        
Equatorial Guinea Native Extant        
French Guiana Native Extant        
Gabon Native Extant        
Gambia Native Extant Yes      
Ghana Native Extant        
Gibraltar (to UK) Vagrant Extant        
Grenada Native Extant        
Guadeloupe (to France) Native Extant        
Guatemala Native Extant        
Guinea Native Extant   Yes    
Guinea-Bissau Native Extant Yes      
Guyana Native Extant        
Haiti Native Extant        
Honduras Native Extant        
Ireland Vagrant Extant        
Jamaica Native Extant       Yes
Liberia Native Extant        
Martinique (to France) Native Extant        
Mauritania Native Extant Yes      
Mexico Native Extant        
Montserrat (to UK) Native Extant        
Morocco Native Extant        
Mozambique Unknown Extant        
Namibia Native Extant        
Nicaragua Native Extant        
Nigeria Native Extant        
Norway Vagrant Extant        
Panama Native Extant        
Paraguay Vagrant Extant     Yes  
Peru Native Extant        
Portugal Vagrant Extant        
Puerto Rico (to USA) Native Extant        
Senegal Native Extant Yes      
Sierra Leone Native Extant        
Sint Maarten (to Netherlands) Native Extant        
Spain Vagrant Extant        
St Kitts and Nevis Native Extant        
St Lucia Native Extant   Yes    
St Martin (to France) Native Extant        
St Vincent and the Grenadines Native Extant        
Sudan Vagrant Extant   Yes    
Suriname Native Extant        
Togo Native Extant        
Trinidad and Tobago Native Extant        
Turks and Caicos Islands (to UK) Native Extant   Yes    
United Kingdom Vagrant Extant        
Uruguay Native Extant Yes      
USA Native Extant Yes      
Venezuela Native Extant        
Virgin Islands (to UK) Native Extant       Yes
Virgin Islands (to USA) Native Extant       Yes
Western Sahara Native Extant        

Important Bird Areas where this species has triggered the IBA criteria

Country/Territory IBA Name IBA link
Anguilla (to UK) Meads Bay Pond site factsheet
Anguilla (to UK) Scrub Island site factsheet
Anguilla (to UK) West End Pond site factsheet
Antigua and Barbuda Offshore Islands site factsheet
Argentina Reserva de Biosfera Albufera de Mar Chiquita site factsheet
Aruba (to Netherlands) San Nicolas Bay Reef Islands site factsheet
Bahamas Booby Rocks and Pirates Bay site factsheet
Bahamas Cay Sal (superseded 26/03/2015) site factsheet
Bahamas Graham's Harbour site factsheet
Bahamas Great Inagua site factsheet
Bahamas Harrold and Wilson Ponds National Park site factsheet
Bahamas Red Bays site factsheet
Bahamas Samana Cay site factsheet
Bahamas South Beach Tidal Flats site factsheet
Benin Lake Ahémé and Aho complex site factsheet
Bonaire, Sint Eustatius and Saba (to Netherlands) Pelkermeer Saltworks, Bonaire site factsheet
Costa Rica Nicoya Gulf mangroves and coastal areas site factsheet
Costa Rica Sierpe Wetlands and Osa Peninsula site factsheet
Cuba Cayería Centro - Oriental de Villa Clara site factsheet
Cuba Gran Humedal del Norte de Ciego de Ávila site factsheet
French Guiana Connétable site factsheet
French Guiana Connétable - Marine site factsheet
French Guiana Plaine Kaw et Pointe Béhague site factsheet
Gabon Akanda site factsheet
Gabon Gamba Protected Areas Complex site factsheet
Gabon Ogooué delta and Mandji island site factsheet
Gambia Niumi National Park site factsheet
Gambia Tanbi wetland complex site factsheet
Gambia Tanji River (Karinti) Bird Reserve site factsheet
Ghana Amansuri wetland site factsheet
Ghana Densu Delta Ramsar Site and vicinity site factsheet
Ghana Keta Lagoon Ramsar Site site factsheet
Ghana Muni-Pomadze Ramsar Site site factsheet
Ghana Songor Ramsar Site site factsheet
Guinea Ile Alcatraz et Ile du Naufrage site factsheet
Guinea Ile Blanche site factsheet
Guinea Rio Kapatchez site factsheet
Guinea-Bissau Arquipélago dos Bijagós site factsheet
Jamaica Black River Great Morass site factsheet
Jamaica Morant Cays and Bank site factsheet
Jamaica Pedro Cays and Bank site factsheet
Liberia Cape Mount site factsheet
Mauritania Banc d'Arguin National Park site factsheet
Mexico Coastal hunedals of the North of the Peninsula of Yucatan site factsheet
Mexico Complejo de Presas de Río Fuerte site factsheet
Mexico Estero Cardonal site factsheet
Mexico Estero Santa Cruz site factsheet
Mexico Laguna Cuyutlán y Estero Palo Verde site factsheet
Mexico Laguna de Tamiahua site factsheet
Mexico Sistema Arrecifal Veracruzano site factsheet
Puerto Rico (to USA) Culebra site factsheet
Senegal Delta du Saloum site factsheet
Senegal Joal-Fadiouth site factsheet
Senegal Parc National de la Langue de Barbarie site factsheet
Sierra Leone Yawri Bay site factsheet
Sint Maarten (to Netherlands) Pelikan Rock, Sint Maarten site factsheet
St Barthelemy (to France) Turtle Island site factsheet
St Lucia Mandele Dry Forest site factsheet
St Lucia North-east coast site factsheet
St Lucia Pitons Management Area site factsheet
St Lucia Point Sables site factsheet
St Vincent and the Grenadines All Awash Island site factsheet
St Vincent and the Grenadines Mustique Island site factsheet
St Vincent and the Grenadines Petit Canouan site factsheet
Trinidad and Tobago West Coast Mudflats site factsheet
Turks and Caicos Islands (to UK) Caicos Bank Southern Cays site factsheet
Turks and Caicos Islands (to UK) East Caicos and adjacent areas site factsheet
Turks and Caicos Islands (to UK) Fish Ponds and Crossing Place Trail, Middle Caicos site factsheet
Turks and Caicos Islands (to UK) Grand Turk Salinas and Shores site factsheet
Turks and Caicos Islands (to UK) North, Middle and East Caicos Ramsar Site site factsheet
USA Altamaha River Delta site factsheet
USA Barrier Island/Lagoon System site factsheet
USA Big Foot Island site factsheet
USA Big Marco Pass Shoal site factsheet
USA Bird Key Stono site factsheet
USA Cape Canaveral-Merritt Island site factsheet
USA Cape Romain National Wildlife Refuge site factsheet
USA Chandeleur Islands (Breton National Wildlife Refuge) site factsheet
USA Crab Bank site factsheet
USA Cumberland Island National Seashore site factsheet
USA Deveaux Bank site factsheet
USA Ferry Slip Island site factsheet
USA Huguenot Park-Nassau Sound site factsheet
USA Jigsaw Islands site factsheet
USA Laguna Vista Spoils site factsheet
USA Lower Tampa Bay site factsheet
USA Sand Bag Island site factsheet
USA Sundown Island site factsheet
USA Tomkins Island site factsheet
USA Turtle Island site factsheet
Virgin Islands (to UK) Anegada: Western salt ponds and coastal areas site factsheet
Virgin Islands (to USA) Saba Island and Cays site factsheet
Virgin Islands (to USA) Southgate and Green Cay site factsheet

Habitats & altitude

Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes suitable non-breeding
Marine Intertidal Salt Marshes (Emergent Grasses) suitable breeding
Marine Intertidal Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc major breeding
Marine Neritic Estuaries suitable non-breeding
Marine Neritic Macroalgal/Kelp major breeding
Marine Neritic Macroalgal/Kelp major non-breeding
Marine Neritic Pelagic suitable breeding
Marine Neritic Pelagic suitable passage
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
Altitude 0 - 100 m Occasional altitudinal limits  


Purpose Primary form used Life stage used Source Scale Level Timing
Pets Whole Adults and juveniles Wild International Non-trivial Recent

Recommended citation
BirdLife International (2016) Species factsheet: Thalasseus maximus. Downloaded from on 25/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 25/10/2016.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Least Concern
Family Laridae (Gulls, Terns, Skimmers)
Species name author Boddaert, 1783
Population size mature individuals
Population trend Stable
Distribution size (breeding/resident) 983,000 km2
Country endemic? No
Links to further information
- Summary information on this species
- Projected distributions under climate change