General

Slaty-backed Gull: Large gull with dark slate-gray back and upper wings; darker outer primaries are separated from mantle by a staggered row of white spots. Underside of primaries are gray; broad white trailing edge to wings. Legs and feet are bright pink and eyes are yellow with red orbital ring; bill is yellow with red spot near tip. Sexes are similar. Winter adult shows brown streaking on head and neck and dark streak through eye. Juvenile is dull gray-brown with white lower belly and black bill; 1st winter is similar but shows more white on face and neck. 1st summer is mostly white with gray-brown mottling and splotches; outer primaries, secondaries, and tail remain dark; bill is black and the legs and feet are pale pink. 2nd year resembles winter adult but has paler wings, brown on nape, sides, belly, and undertail, and has dark spot at tip of yellow bill; retains black-tipped yellow bill through third winter.

Range and Habitat

Slaty-backed Gull: Coastal species of northeast Asia. Rare in coastal Alaska, most frequent in the Bering Sea. Casual in winter south to Pacific states.

Breeding and Nesting

Slaty-backed Gull: Colonial; seaweed nest on seacliffs, rocky, islands, or occasionally sandy beaches. Two to three brown or olive buff eggs spotted with brown or black. Incubation ranges from 26 to 28 days and is carried out by both sexes; first flight at 49 to 56 days.

Foraging and Feeding

Slaty-backed Gull: Forages on mudflats; omniverous; fish, seabird eggs and young, dead animals and birds, entrails.

Vocalization

Slaty-backed Gull: Deep, gutteral "kaaw," or "klaaw."

Similar Species

Slaty-backed Gull: Winter Western Gull has thicker bill, more extensive black on primary tips, absence of streaking on head and neck.