Common Tern/Sterna hirundo - Photographer: Frank Schulkes
Common Tern/Sterna hirundo - Photographer: Plamen Dimitrov
Common Tern/Sterna hirundo - Photographer: Борис Белчев
Common Tern/Sterna hirundo - Photographer: Иван Иванов

L 34-37 cm (incl. tail-streamers 5-8 on ad.), WS 70- 80cm. Breeds colonially or singly both at coasts and at inland waters (lakes, rivers, etc.). Summer visitor (Apr-Oct), winters in W and S Africa. Food fish. Nest is scrape on ground.
IDENTIFICATION: Very similar to Arctic Tern, but, with practice, separation nearly always possible. Apart from being slightly larger, different structure when perched useful: longer bill (often looking slightly decurved) and head, and longer legs (belly well clear of ground). Different structure also in flight: longer neck/head and slightly broader wings, which appear to be more or less central on body. Hovers, and dives directly for fish. - Adult summer: Bill orange-red with black tip, but note that black tip can be very small, especially by midsummer; underparts pale grey, usually without obvious contrast with white cheek; short tail-streamers not extending beyond wing-tip; outer 4-6 primaries darker than rest, forming dark wedge on upperwing, but note that wedge often is very faint in spring (only a dark ‘notch’ at trailing edge), becoming obvious by midsummer through wear; from below, primaries white with broad, rather diffuse dark trailing edge; translucency strongest on inner primaries. - Adult winter (some start moult in Jul; Arctic not until reaching winter range): White forehead and underparts, dark carpal bar, and all-black bill. - Juvenile: Upperwing has pale squareshaped midwing-panel between narrow grey secondary bar and obvious dark carpal bar; other differences from Arctic include: a little orange at base of bill (bill all black on Arctic from late summer); forehead and upperparts obviously ginger-brown in tone when recently fledged; extensive carpal bar usually visible when perched (smaller on Arctic, usually concealed). - 1stsummer (usually stays in winter range; rare in Europe): White forehead and underparts; blackish bill; wholly or partly retained juvenile wings and tail much worn, giving striking variegated pattern. - 2nd-summer (many stay in winter range, scarce in Europe): Like adult summer, but has immature features such as white on forehead, patchy grey underparts, and blackish bill.
VOICE: Noisy at colonies, including short, sharp ‘kit’, rapid series of quarrelling ‘kt-kt-kt-kt-…’ and typical ‘kierri-kierri-kierri-…’ with variations. Alarm is a disyllabic, drawn-out, downslurred ‘kreee-arrr’ or a sharp ‘chip!’.

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