Birds in Bulgaria

L 38-46 cm (excl. exposed feet c. 4), WS 61-73 cm. Commonest auk in British Isles. Nests on bare, narrow cliff-ledge on steep coastal cliffs, in often large colonies. Single egg laid directly on ledge, pear-shaped to prevent rolling off, incubated by bird standing up. Parents recognize egg by pattern and young by voice. Young jumps from cliff when three weeks old, still not fledged, tended at sea by male alone.
IDENTIFICATION: Head and upperparts brownish, underparts white. Percentage of distinctive ‘bridled’ variety (see plate) increases towards north. At close range slender, pointed bill obvious. Greatest risk of confusion with Brünnich’s Guillemot (see right), but much more common problem is to distinguish Guillemot from Razorbill at long range, when bill shape becomes surprisingly difficult to see. Guillemot has paler greyish-brown upperparts (Razorbill appearing almost black); difference obvious in W Europe (esp. small race albionis of S Britain is pale), less obvious but still present in N Norway. Also, Guillemot is slightly larger than Razorbill - in mixed ‘trains’ Guillemots are usually longer-bodied (but beware of variation, and in winter larger birds from the north may in some areas mix with smaller in the south). Variable amount of dark streaking on flanks, in ‘wingpits’ and on underwingcoverts, but some populations (e.g. S Britain and Baltic) average less streaked and some unstreaked (Razorbill always pure white). Further, flying Guillemot usually told by wide, dark brown rump area, generally with uneven border to narrow white rump-sides (Razorbill has narrower, black central rump band, broadly and evenly bordered pure white in Long-tailed Duck fashion); feet projecting beyond tip of short tail, giving ‘untidy’ end to stern (feet tucked neatly beneath tail on Razorbill); slightly hunchbacked outline (Razorbill appears straighter-backed); and wings set a trifle ahead of centre (wings appear central on Razorbill). - Adult winter: Amount of white on side of head varies, just as on Razorbill, but Guillemot generally appears more whiteheaded. Acquires summer plumage early, (Nov) Dec-Feb, and can then be distinguished from 1st-winters, which moult later. - 1st-summer: Like adult, except variable amount of white on throat, and retained juvenile flightfeathers much faded, brownish.
VOICE: Vocal in colony, e.g. ‘stomach-rumbling’ ‘mmm …’; hard and nasal notes repeated in staccato, ‘ha ha ha ha …’, turning into prolonged bellowing ‘… ha-aahr’, etc. Young give high-pitched, disyllabic ‘plee-ü’ after leaving nest.