Birds in Bulgaria

L 42-50 cm, WS 71-85 cm. Breeds on boreal forest lakes and marshes, tundra pools, also on temperate shallow fresh waters. Migratory in N, wintering largely in marine habitats, also lakes and reservoirs. Gregarious except when nesting. Vegetarian; often grazes on arable fields in winter.
IDENTIFICATION: Medium-sized, short-necked, with rounded, comparatively large head, small bill and pointed tail. In flight, these characters apparent as well as narrow neck, pointed wings, and outer wing generally swept back. Flight fast. In all plumages, note distinct white belly patch. Axillaries and underwing-coverts dusky pale grey (cf. American Wigeon). - Adult male breeding: Unmistakable; head and neck chestnut, forehead and crown creamy-yellow, breast greyish-pink, rest of body grey with white and black stern. In flight, large white patch on upper forewing striking, speculum green. - Adult female: Rather dull rufous-brown or greyish (some variation, with inclination towards two morphs) with variable diffuse mottling and blotching (some are rather plain), best recognized by: rather dark plumage; shape; small, pale blue-grey bill with black tip; and contrasting white belly. Speculum dull, dark; innermost secondaries usually edged pale, forming narrow whitish patch (recalling 1st-year female Gadwall). -Adult male eclipse: Resembles adult female but retains white upper forewing, and plumage more rufous-tinged. - Juvenile: As adult female, but white underparts often faintly mottled, and speculum still duller. - 1st-year male: As adult male breeding, but upper forewing is chiefly greybrown, not largely pure white.
VOICE: male has characteristic loud whistling glissando note, often preceded by low, brief note (and ending with subdued dry trill), ‘wu, weeoo( rr)’; at a distance only ‘wee-oo’ audible. Also more subdued, conversational ‘wip… wee… wip-wü’, etc., somewhat recalling a Tufted Duck. In autumn, and at times at other seasons as well, coarse, snorting ‘rrah’, ‘ra-kaah’ and variants are heard. Flight-call of female is a repeated growling, ‘karr karr karr …’, recalling Great Crested Grebe in tone.