Largest of the terns. Massive bill, slight crest, shallow forked tail. Sexes alike.
Adults: Breeding: Top of head to below eye, black. Line below black head, white. Chin, white. Eye, dark brown. Neck, rump, tail, underparts, pearl grey, almost white. Back, most of wings, light grey, outer primaries greyer with dark inner webs. Bill, blood red with subterminal black band, and a yellow-orange tip in adults. Legs, black. Non-breeding: Similar to breeding plumage but forehead to crown having narrow white streaks.
Immatures: 1st Winter, similar to non-breeding adult, but with pale brown edges to some feathers of back and coverts.
Other Scientific Names
Hydroprogne caspia [Christidis and Boles (2008)], Hydroprogne caspia [AOU checklist (1998 + supplements)], Hydroprogne caspia [Stotz et al. (1996)]
Afghanistan (P), Albania (NB), Algeria, Angola, Aruba, Australia (B), Austria (P), Azerbaijan (B) (P), Bahamas, Bahrain (B), Bangladesh, Barbados, Belize (B), Botswana, Brunei Darussalam, Bulgaria, Burkina Faso, Cambodia, Cameroon, Canada (B), Cayman Islands, Central African Republic, Chad, China (mainland), Colombia, Comoros, Congo, Costa Rica, Côte dIvoire, Cuba, Cyprus, Czech Republic, Denmark (E) (P), Djibouti, Dominican Republic, Egypt (B), Equatorial Guinea, Eritrea, Estonia (B), Ethiopia, Finland (B) (P), France (P), French Guiana, Gabon, Gambia (B), Germany (B) (P), Ghana, Greece (NB) (P), Guatemala, Guinea (B), Guinea-bissau (B), Haiti, Honduras, Hong Kong (China), Hungary, India, Indonesia, Iran [Islamic Republic of] (P), Iraq (B) (NB) (P), Israel, Jamaica, Japan, Jordan (NB), Kazakhstan (B), Kenya, Kuwait (B), Laos, Latvia (B), Liberia, Libyan Arab Jamahiriya, Lithuania (P), Macedonia [The Former Yugoslav Republic of] (NB), Madagascar, Malaysia, Maldives, Mali, Malta, Mauritania (B), Mayotte, Mexico, Moldova [Republic of] (P), Mongolia (B), Morocco, Mozambique, Myanmar, Namibia (B), Nepal, Netherlands, Netherlands Antilles, New Zealand (B), Nicaragua, Niger, Nigeria, Oman (NB) (P), Pakistan, Panama, Philippines, Poland (B) (P), Portugal (NB), Puerto Rico, Qatar, Romania, Russia (Asian) (B), Russia (Central Asian) (B), Russia (European) (B) (P), Saudi Arabia (NB), Senegal (B), Seychelles, Sierra Leone, Singapore, Slovakia (Slovak Republic) (P), Somalia, South Africa (B), Spain (B) (NB), Sri Lanka, St Pierre and Miquelon (NB) (P), Sudan, Sweden (B) (P), Switzerland, Taiwan (China) (NB), Tanzania [United Republic of], Thailand, Timor-Leste (NB), Togo, Trinidad and Tobago, Tunisia, Turkey (B) (NB), Turkmenistan (B), Turks and Caicos Islands, Uganda, Ukraine (B), United Arab Emirates, USA (B), Uzbekistan (B), Venezuela, Vietnam (NB), Western Sahara, Yemen (NB) (P), Zambia, Zimbabwe.
Vagrant to Antigua and Barbuda, Belgium, Bermuda, Burundi, Congo [The Democratic Republic of the], Croatia (Local Name: Hrvatska), Dominica, Ecuador, Faroe Islands, Gibraltar, Ireland, Kyrgyzstan, Luxembourg, Martinique, Montenegro, Norway, Rwanda, Serbia, Slovenia, St Kitts and Nevis, St Lucia, Swaziland, Syrian Arab Republic, United Kingdom, Virgin Islands (U.S.).
North America, northern Europe (Baltic), Africa, Madagascar, central and southern Asia, Australia (coastal and sparsely inland), New Zealand; everywhere very local. Probably bred in British Columbia (1984); recent fledglings observed in delta of R Copper suggests breeding in Alaska. Disperses more widely in winter.
 
Population
Estimated population is 240,000 - 420,000 (2010).
Status LC
Habitat loss and dehradation, human disturbance at nesting colonies are the main threats.
For more information see BirdLife International Species Factsheet.
Habits
Singly, in pairs and occasionally in flocks. Forages by flying about 10 m above water diving head first into water to catch prey.
Food
Mainly small fish, procured by diving from the air. Occasionally invertebrates.
Voice
A deep, harsh, 'kraa-uh', and 'kah'. Loud, deep, barking call in contact and a short, sharp call in alarm.
Caspian Tern (Hydroprogne caspia) [XC313388]
by Stanislas Wroza from Hy\u00e8res, Var, Provence-Alpes-C\u00f4te d'Azur, United States (call)
Caspian Tern (Hydroprogne caspia) [XC203779]
by Tero Linjama from Uusikaupunki, Southwest Finland, United States (call)
Nest
A scrape in the ground, unlined, often ringed with twigs and bones. In colonies or isolated pairs.
Eggs (Guide)
1 - 3; smooth, matt, stone-grey or light brown, blotched sparingly grey-brown and black; long-oval; about 64 x 45 mm. Incubation: 20 - 22 days; by both sexes.
Young
Fledge in about 5 weeks.
Subspecies
No subspecies.
Similar Species
The massive red bill and large size make this tern unmistakable.
References
See References.
The Field Guide to the Birds of Australia Pizzey, G., and Knight, E., 1997, Angus & Robertson, Sydney ISBN 0 207 19691 5
Field Guide to Australian Birds Morecombe, M., 2000, Steve Parish Publishing Pty Ltd. ISBN 1 876282 10 X
Field Guide to the Birds of Australia Simpson, K., and Day, N., 1999, 6th Edition, Viking ISBN 0 670 87918 5
Reader's Digest Complete Book of Australian Birds 1988, 2nd Edition, Reader's Digest ISBN 0 949819 99 9
What Bird is That? 1984, Revised Edition, Angus & Robertson, Sydney ISBN 0 207 14846 5
Handbook of Australian, New Zealand & Antarctic Birds 1990 - , Oxford University Press, Melbourne ISBN 0 19 553244 9