From Opus

Photo by avesdigital
Photo taken: Tarifa, Spain

Sterna caspia

[edit] Identification

48–56 cm. White head, neck, belly, tail, cap is black in breeding plumage, mottled with white in winter and in juvenile, pale grey back and upper wings, pale, dark tipped underwings, black legs, red-orange bill.

Photo by john-henry
Portugal, November 2008

[edit] Distribution

North America, West Indies and northern South America, Europe, Asia, Africa, Australia and New Zealand.

There are records most years for the British Isles.

[edit] Taxonomy

This is a monotypic species^[1] in spite of its cosmopolitan range (some authorities do recognize two subspecies: caspia and imperator).
Sometimes Caspian Tern is considered part of genus Hydroprogne; this is the case with those authorities recently updated, so it is likely that Opus in the future will have to change as well.

[edit] Habitat

Large lakes and ocean coasts. Breeds on sandy coasts and islands.

Mating Dance Photo by Robert Davis Bolivar Flats, May 2008

Juvenile Photo by blubird Las Gallinas, California, July 2008

[edit] Behaviour

[edit] Diet

The diet includes fish, insects, eggs and young birds.

[edit] Breeding

They are ground nesters, colonially and singly; 1-3 pale blue green eggs, heavily spotted brown, are laid in a bare scrape.

[edit] Vocalisation

The call is a loud croak.

[edit] References

1. Clements, JF. 2008. The Clements Checklist of Birds of the World. 6th ed., with updates to December 2008. Ithaca: Cornell Univ. Press. ISBN 978-0801445019. Spreadsheet available at http://www.birds.cornell.edu/clementschecklist.
2. Wikipedia
3. Collins Field Guide 5th Edition
4. Collins Bird Guide ISBN 0 00 219728 6

[edit] External Links