English: Caspian Tern
Russian: Чеграва
Mongolian: Морин шунгуулай, Морин хараалай
German: Raubseeschwalbe
French: Sterne caspienne
Japanese:  オニアジサシ (Oni-ajisashi)

Body length: 48-55 cm.
Wing span: 96-111 cm.

Breeds colonially or singly, mostly on more remote offshore, low islands. Summer visitor (Apr-Oct; in Britain & Ireland about 5 records annually), winters in W Africa, occasionally Mediterranean Sea. Migration partly over land, following rivers over European continent, and crossing W Sahara in Mar and Nov. Food mainly fish, which during breeding can be caught far from colony (30-60 km, or more), often in fresh water. Nest is bare scrape on ground (sand or rocks).

Identification: Largest tern; wingspan larger than Common Gull. Slow wingbeats and flight more ponderous than other terns, is more gull-like; also, looks decidedly front-heavy in flight. Very large red bill and extensive dark (blackish) under primaries at all ages.

• Adult: Bill bright red, with small dark subterminal mark on most; legs black. In winter, black on head extensive, not thin-masked pattern of most other terns. Juvenile: Full dark cap, extending further down on lores and cheeks than on adult; dusky-tipped orange bill; pale legs; rather faint dark markings on upperparts and tail; and inner wings rather uniformly pale, lacking obvious dark carpal bars of other large terns.
  
• 1st winter: Orange-red bill (only slightly paler than ad.winter) and dark legs develop quickly during first autumn. Forehead usually becomes slightly paler, too (still streaked dark), much as on adult winter.
  
• 1st summer: As adult winter, except wings and tail much worn or with obvious variegated pattern through moult.