English: Black Tern      

Russian: Чёрная крачка

Mongolian: Хилэн хараалзай, Хилэн хараалай

German: Trauerseeschwalbe

French: Guifette noire

Japanese:  ハシグロクロハラアジサシ (Hashiguro-kurohara-ajisashi)

Body length: 22-26 cm.
Wing span: 56-62 cm.

Commonest marsh tern, breeding in freshwater marshes with patches of low, floating vegetation, often among Black-headed Gulls for protection. Summer visitor (mainly late Apr-Sep), winters in Africa. In Britain & Ireland, occasional large migrant gatherings or coastal passage, but seldom numerous.

Identification: Adult summer: All-black head and body, rather uniform dark grey upperparts, white undertail, and dark legs and bill; head and underparts mottled or patched with white on moulting adults in spring (before May) and summer/autumn (white feathers on head already appearing in Jun).

• Adult winter (head and body plumage fully acquired Sep onwards); Much as juvenile, but upperparts plain grey, lacking scaliness, and outer 5-7 primaries darker than rest.
• Juvenile: Extensive black cap and obvious dark breast-side patches; scaly pattern on darkish saddle and wing-coverts; darker carpal and secondary bars; and outer primaries not contrastingly darker than inner. Could be mistaken for juvenile Common /Arctic Tern, but more smaller size, shorter, less forked tail, slightly shorter wings, and dark breast-side patches; mode of flight (see above under ‘Marsh terns’) also good clue.
• 1st summer (usually stays in winter range): Variable; like adult winter but usually differing in having darker, more worn outer primaries and darker secondaries, and on some a few scattered dark feathers on underbody and head (these safely told only in May-Jun from moulting ad.)