Caspian Tern, Reuzenstern, Raubseeschwalbe, Gaivinha-de-bico-vermelha, Pagaza Piquirroja
Spotted in the Alentejo region of Portugal. Caspian Tern sound
The Caspian Tern (Hydroprogne caspia, formerly Sterna caspia; syn. Hydroprogne tschegrava, Helopus caspius) is a species of tern, with a subcosmopolitan but scattered distribution. Despite its extensive range, it is monotypic of its genus, and has no subspecies accepted either. In New Zealand it is also known by the Maori name Taranui.

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It is the world’s largest tern with a length of 48–60 cm (19–24 in), a wingspan of 127–145 cm (50–57 in) and a weight of 530–782 g (1.2-1.8 lb). Adult birds have black legs, and a long thick red-orange bill with a small black tip. They have a white head with a black cap and white neck, belly and tail. The upper wings and back are pale grey; the underwings are pale with dark primary feathers. In flight, the tail is less forked than other terns and wing tips black on the underside. In winter, the black cap is still present (unlike many other terns), but with some white streaking on the forehead. The call is a loud heron-like croak.
Their breeding habitat is large lakes and ocean coasts in North America (including the Great Lakes), and locally in Europe (mainly around the Baltic Sea and Black Sea), Asia, Africa, and Australasia (Australia and New Zealand). North American birds migrate to southern coasts, the West Indies and northernmost South America. European and Asian birds spend the non-breeding season in the Old World tropics. African and Australasian birds are resident or disperse over short distances.
The global population is about 50,000 pairs; numbers in most regions are stable, but the Baltic Sea population (1,400–1,475 pairs in the early 1990s) is declining and of conservation concern.
The Caspian Tern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
They feed mainly on fish, which they dive for, hovering high over the water and then plunging. They also occasionally eat large insects, the young and eggs of other birds and rodents. They may fly up to 60 km from the breeding colony to catch fish; it often fishes on freshwater lakes as well as at sea.
Breeding is in spring and summer, with one to three pale blue green eggs, with heavy brown spotting, being laid. They nest either together in colonies, or singly in mixed colonies of other tern and gull species. The nest is on the ground among gravel and sand, or sometimes on vegetation; incubation lasts for 26–28 days. The chicks are variable in plumage pattern, from pale creamy to darker grey-brown; this variation assists adults in recognizing their own chicks when returning to the colony from feeding trips. Fledging occurs after 35–45 days.







Other synonyms:
Afrikaans: Reuseseeswael , Reusesterretjie
 Asturian: Chirri Picarroxa, Picarroxa
 Breton: Ar skrav-Kaspia
 Catalan: Fumarell d’ala blanca, Llambritja de bec vermell, Xatrac gros
 Catalan (Balears): Llambritja de bec vermell
 Valencian: Fumarell d’ala blanca
 Czech: Rybák velkozobý
 Welsh: Morwennol fwyaf
 Danish: Rovterne
 German: Raubseeschwalbe, Raub-Seeschwalbe, Riesenseeschwalbe
 Maldivian: Miyaremu Dhooni
 English: Caspian Tern, Taranui
 Spanish: Charrán Caspia, Gaviota Caspia, Gaviota golondrina caspiana, Gaviota Picorojo, Gaviota Real Grande, Gaviota Real?, Gaviotín de Pico Rojo, Gaviotín Piquirrojo, Golondrina-marina Caspica, Pagaza Mayor, Pagaza Piquirroja, Pagaza Piquirrojo
 Spanish (Colombia): Gaviotín Piquirrojo
 Spanish (Costa Rica): Pagaza Mayor
 Spanish (Cuba): Gaviota Real Grande
 Spanish (Dominican Rep.): Charrán Piquiroja, Gaviota Picorojo, Gaviota Real
 Spanish (Honduras): Gaviota golondrina caspiana
 Spanish (Mexico): charrán caspia, Golondrina-marina Caspica
 Spanish (Nicaragua): Pagaza Piquirroja
 Spanish (Venezuela): Gaviota Cáspica
 Estonian: räusk, Räusktiir, räusktiir (räusk), Räusktiir e. räusk, Räusktiir, räusk
 Basque: Txenada mokogorria, Xatrac gros
 Finnish: Räyska, Räyskä
 Faroese: Brituterna
 French: Sterne caspienne, Sterne tchégavra
 Irish: Geabhróg Chaispeach
 Galician: Carrán do Caspio, Xatrac gros
 Haitian Creole French: Gwo Mòv bèk jòn
 Croatian: Velika ?igra
 Hungarian: Lócsér
 Indonesian: Daralaut Caspia
 Icelandic: Ránþerna, Stormsvala
 Italian: Sterna maggiore, Uccello delle tempeste
 Japanese: oniajisashi, Oni-ajisashi
 Latin: Hydroprogne caspia, Hydroprogne tschegrava, Sterna caspia, Sterna caspica, Sterna tschegrava
 Lithuanian: Plešrioji žuvedra
 Malagasy: Samby, Trobaky, Varevaka
 Maori: taranui, Tara-nui
 Malay: Camar Caspian
 Dutch: Reuzenstern
 Norwegian: Rovterne
 Polish: Rybitwa krótkodzioba
 Portuguese: andorinha do mar grande, Andorinha-do-mar-grande, Gaivina-de-bico-vermelho, Gaivina-de-bisco-vermelho
 Romansh: Pestgarel caspic
 Russian: Chegrava
 Slovenian: kaspijska cigra
 Albanian: Dallëndyshe deti e madhe
 Serbian: velika cigra
 Swedish: Skräntärna
 Swahili: Shakwe Domo-kubwa
 Turkish: Büyük Sumru, Hazar sumrusu
 
Travel Birdwatching Holiday Alentejo, Vacation Portugal for birders to see birds on your trip.