Appearance:

Very similar to Herring Gull, and not always possible to identify with certainty. Generally thicker neck, rounder head and longer wings than Herring Gull. Adults: Silvery upperparts, bright yellow legs (beware that it is not uncommon for Herring Gull to have yellow legs!), and more black and less white in wing-tips. Bill heavier than H.G. with markedly curved tip. Orbital ring red, not orange. Big, red gonys spot, often extending to upper mandible. Marked gonys angle. Primary feather P5 (counted from innermost feather in gulls) usually with broad, black band. In winter plumage head is less streaked than in H.G., and often completely white. Immatures first winter: Pale belly and head. Dark underwings with blotchy markings. Only vague pale window of inner primaries, and well defined, wedge-shaped tail-band. Dark base of bill. For a detailed account of all plumages see Gull Research.

Sound:

Voice more nasal than Herring Gull, but ID by sound difficult.

Distribution:

Wikipedia: map (se also Xeno-canto below)

Ecology:

Birdlife ecology

Links:

Observation.org Latest observations

Video IBC

Image search Flickr NB! May give other species

Sound search at Xeno-canto

Featherbase

CC

Appearance:

Yellow legs, black to dark grey back (regional variations) and black primaries with only small white spots. Generally more slender than Herring Gull and Great Black-backed, with longer and more narrow wings, and longer legs. Winter plumage with streaked head and neck. Underside of flight feathers smoky grey. Juveniles very variable, but generally darker than Herring Gulls. Young birds with completely dark inner primaries and broad terminal band to tail.

Sound:

Very similar to Herring Gull, but tone more nasal.

Distribution:

Wikipedia: map (se also Xeno-canto below)

Ecology:

Birdlife ecology

Links:

Observation.org Latest observations

Video IBC

Image search Flickr NB! May give other species

Sound search at Xeno-canto

Featherbase

CC

Sounds:Recorded by Peter Boesman,http://www.xeno-canto.org ,CC license