Adult Description
- Medium-sized gull.
- Back slaty gray.
- Underparts white.
- Wingtips black, without extensive white markings.
- Entire head black in breeding season.
Immature Description
Juvenile Dusky brown overall. Head gray brown, paler on forehead and chin. Black spot in front of eyes, white crescents above and below eyes. Back and wings dusky brown with broad paler tips, giving a scaly look.
First winter (Basic I) plumage: Back gray, but wings brown. Head pale with dusky gray markings behind eye, darker and more extensive than adult's. Nape gray. Breast, sides of neck, and sides of flanks dark gray. Tail white at base with broad blackish subterminal band.
First summer (Alternate I) plumage: Like first winter, but paler. May have some black spotting on head. Underparts more white. Reaches full adult plumage in third year.