Size: L: 35 cm Wt: 200-250 g. Males and females are similar. Seasonally dimorphic. This species requires two years to reach full adult plumage.

Adult summer/Second summer: mantle pale grey, with black wing-tips; head with black hood; underparts and tail white; bill black; legs red

Adult winter/Second winter: mantle pale grey, with black wing-tips; head white with black spot behind eye; underparts and tail white; bill black; legs red

Juvenile: mantle rich brown; head with extensive blackish markings; sides of breast with rich brown; rest of underparts whitish; tail whitish or white, with black band; bill black; legs pinkish

Nestling: semiprecocial and downy; upperparts and head yellowish-buff, with blackish-brown mottling; breast pale cinnamon; flanks and belly grey; bill flesh-coloured, with large blue-black tip; legs pinkish