Birds in Bulgaria

L 115-127 cm (body c. 60), WS 170-195 cm. Breeds on far NE tundras by the Arctic Ocean, winters in NW Europe.
IDENTIFICATION: Very large. A smaller version of Whooper Swan, with proportionately slightly shorter neck, bigger head and more compact body and bill; these differences often difficult to appreciate when observing single birds. Safest separation by pattern of bill, Bewick’s having slightly less yellow than black (ssp. bewickii, Europe), the yellow generally a square or rounded patch (diagnostic), rarely more wedge-shaped (recalling Whooper, but yellow not reaching in front of nostril, and black around gape more solid). Also, with experience, voice is good clue (see below). - Variation: Very rarely N American vagrants (ssp. columbianus, ‘Whistling Swan’) occur, distinguished by practically all-black bill (only a tiny yellow patch in front of eye). - Juvenile: Greyish (often a shade darker than Whooper). Bill pattern of adult discernible (black of adult is pink, yellow is off-white).
VOICE: Vocal. Calls similar to those of Whooper Swan but less bugling, more yapping or honking, and on average higher-pitched (large overlap; flight-call rather deep) and softly ‘bent’ (diphthong impression). Also, notes not repeated in threes or fours, usually in twos, or given singly.