Caspian Tern

Sterna caspia

As large as a big gull, the Caspian Tern is the largest tern in the world. Its large coral red bill makes it one of the most easily identified terns throughout its worldwide range.

Interesting Information

  • The oldest known wild Caspian Tern lived to be more than 26 years old. Average life span of Great Lakes Caspian Terns is estimated to be 12 years.

  • The Caspian Tern aggressively defends its breeding colony. It will pursue, attack, and chase potential predatory birds, and can cause bloody wounds on the heads of people who invade the colony. The entire colony will take flight, however, when a Bald Eagle flies overhead, exposing the chicks to predation from gulls.

  • The largest breeding colony in North America is off the coast of Oregon. Increasing numbers of terns at this site have caused problems with young salmon releases, some of them endangered species. Efforts are being made to move the colony to other areas, away from the fish stocking programs.

  • Young Caspian Terns appear to have a difficult time learning to catch fish efficiently. They stay with their parents for long periods of time, and are fed by them even on the wintering grounds. Many young terns do not return to the nesting grounds for several years, remaining instead on the wintering areas.


Adult Description

  • Length Range: 48-58 cm (19-23 in)

  • Weight: 635 g (22.4 oz)

  • Size: Large (16 - 32 in)

  • Large, gull-like tern.

  • Black cap.

  • Body white.

  • Bill large, thick, and brilliant red with dark tip.

Sex Differences

Sexes Similar


Juvenile has blackish crown, black edging to back feathers.


Photo taken from: The Sibley Field Guide by David Allen Sibley

© 2003 Cornell Lab of Ornithology


  • Breeds in wide variety of habitats along water, such as salt marshes, barrier islands, dredge spoil islands, freshwater lake islands, and river islands.

  • During migration and winter found along coastlines, large rivers and lakes. Roosts on islands and isolated spits.


Flies over water with bill pointing down; plunges into water to catch fish.


Almost entirely fish; occasionally crayfish and insects.



Kingdom: Animalia
Phylum: Chordata
     Subphylum: Vertebrata
Class: Aves
Order: Charadriiformes
Family: Laridae
    Subfamily: Sterninae
Genus: Sterna
Species: Sterna caspia

Similar Species

  • Larger and more robust than other terns. Pointed red bill and black cap distinguishes it from gulls.

  • Royal Tern thinner with thinner wings, has thinner more pointed orange or orange-red bill, more deeply notched tail, and outside of the breeding season, an extensive white forehead.

Bird Sound

Call a raspy "kowk." Juvenile begging call a high pitched whistling; heard frequently during migration and in winter.

Eggs look like this

Photo taken from: ARCTOS Collaborative Collection Management Solution