Gavia immer
Large and bulkily built diver with heavy bill, square head profile and steep forehead. Usually holds bill pointed straight, not uptilted like White-billed Diver. Summer: White underparts and chequered black back. Black bill and head. Neck with white band. Winter; white underparts and dark back. Neck with incomplete black band, creating contrasting, jagged edge. Heavy, goose-like flight.
Song: Like a slow Black-throated Diver. Pitch slowly rising with a register break, progressing into a cyclic, two to four syllable, motif. Also various vibrating eerie descending calls. Often used as sound effect in horror movies.
Wikipedia: map (se also Xeno-canto below)
Birdlife ecology
