Birds in Bulgaria

L 44-52 cm, WS 117-128 cm. Still one of world’s rarest gulls, but significant increase in W Mediterranean in recent years. Nests colonially or singly on rocky, small islands. Strictly coastal or pelagic, frequenting wave-washed rocky coasts and bays or sandy beaches. Rarely scavenges like other large gulls, but feeds almost exclusively on fish, snatched in flight from near surface or in deeper plunge-dives.
IDENTIFICATION: Four age-groups (see p. 168). Slightly smaller than Herring Gull, with more elegant general appearance; shorter, stubbier bill; more elongated forehead with feathering expanding towards nostrils; longer neck when alert; longer, narrower wings; flies more gracefully, with more gliding; bill often pointing slightly down when perched. In breeding areas, Yellow-legged Gull is only similar adult gull, from which told by dark red bill (looks black at distance), dark iris, dark grey or greenish legs (often visible in flight, too), much paler grey and slightly two-toned upperwing lacking broad, clear-cut white trailing edge, and has only tiny white ‘mirror’ at wing-tip; small white primary tips, like ‘string of beads’. - 1st-year: Juvenile similar to Yellow-legged and Lesser Black-backed Gulls, but underwing more strongly patterned with dark-barred coverts and dark flightfeathers separated by light midwing-panel; rump darkish, but white uppertailcoverts forming prominent U; largely black tail-feathers broadly tipped white; lower flanks usually dark; legs dark grey; bill deepest at tip, twotoned, tip black and inner two-thirds grey. Develops adult-like upperbody early, gaining many pale grey feathers on scapulars and mantle Feb-May. - 2nd-year: Told by pale grey upperparts; ‘smart’ wing pattern with dark and neat secondary bar; narrow black tail-band; dark legs; and usually red-based bill. - 3rd-year: Like adult, but a little black on primary coverts; ‘mirror’ lacking; and sometimes hint of tail-band.
VOICE: Calls when breeding include a nasal ‘gleh-i-eh’, low ‘ug-ug-uk’ (alarm) and harsh, raucous ‘argh’ in endless series, recalling the noise in a rookery.