Birds in Bulgaria

L 50-58 cm, WS 125-140 cm. Breeds on rocky islands and damp, elevated coastal moors, usually in loose colony; winters in N and S Atlantic. In Britain & Ireland, breeds in Scotland and seen irregularly along coasts, especially during or after autumn storms. Food mainly fish, taken from surface of sea or from other birds, or behind trawlers. Nest a shallow depression, defended with fierce dives.
IDENTIFICATION: Large and heavy, roughly of Herring Gull size. In flight, all dark with large white primary patches above and below. Bill heavy. Heavy and neck powerful. Central tail-feathers broad, tips rounded, not or only slightly projecting. Soars more frequently than congeners, can give Buzzard-like impression. Floats high on sea. - Adult summer: Coarsely streaked yellow-brown on nape, neck and upperparts, female on average more so. - 1st-year: More uniformly brown than adult and tinged reddish-brown, especially below; the white ‘flashes’ on upper ‘hand’ often less extensive and prominent than on adult. - Main risks of confusion with young large gull (esp. an oiled one) and with juvenile Pomarine Skua or, at distance, adult dark-morph Pomarine. Told from young gull by flight being more steady and purposeful, wings beating more flexibly (wingbeat pace otherwise similar); proportionately heavier body (‘flying barrel’); broader wing-bases but often more pointed ‘hand’; and - most reliably - white wing patches (see above). From juvenile Pomarine by heavier body and flight; lack of light cross-barring (thus never has contrasting pale rump, vent or underwing-coverts); often slightly darker head than rest of body (Pomarine usually uniformly dark, or head a shade paler than chest); broader and proportionately somewhat shorter wings; and generally clearly larger and purer white wing patches reaching right in to arm. (However, some juv. Great Skuas have confusingly restricted patches on upperwing.) From adult dark-morph Pomarine by silhouette and flight, and certainly by lack of broad, long tail projections (though can be absent through moult on Pomarine).
VOICE: Silent away from breeding grounds. There, single or series of short, slightly nasal ‘gok’ can be heard; in display utters squeezed, rolling ‘chirr’.