Morus bassanus
White with black wing tips and yellow-buff at back of head. Juveniles brown with small pale speckles, white u-shaped rump patch and pale underparts. Fully coloured only after 5 years, and patchy, intermediate plumages often seen. Unmistakable bird at close range or with favorable light, but can be confused with shearwaters at a distance and/or in strong wind. Differs from those by long tail and much longer neck and head. Alternates between powerful, even and shallow wing-beats and glides. Flight becomes more shearwater-like in strong winds.
Heard mostly at breeding ground. Even, rhythmical series of harsh "harrr, harrr, harrr,".
Wikipedia: map (se also Xeno-canto below)
Birdlife ecology
Sounds:Recorded by Elias A. Ryberg,http://www.xeno-canto.org ,CC license
