Slaty-backed Gull Identification

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Slaty-backed Gull Photos and Videos

Breeding adult

A large, stocky, pot-bellied gull with short pink legs, short wings, and a hefty bill. Breeding adult has a white head and underparts, dark gray upperparts, and a yellow bill with a red spot.

Nonbreeding adult

Nonbreeding adult has a heavily streaked head and upper breast. In flight, adult shows an all-white tail, a broad white trailing edge on the inner wings, and a diagnostic “string of pearls” pattern near the wingtips: small white arcs separating the dark gray feathers from black wingtips.

Nonbreeding adult

A large, full-bodied gull with pink legs in all plumages. Nonbreeding adult has dark gray upperparts, a broad white tertial crescent in front of the black-and-white wingtips, a yellow bill with red mark, and a heavily streaked head with a darker patch around the eye.

First year

Slaty-backed Gulls take four years to transition to full adult plumage. First year birds are quite variable, but note the short pink legs, thick black bill, dark mask around the eye, and brown wingtips and tail.

First year

First-winter birds can look pale and bleached.

Breeding adult

An opportunistic, omnivorous feeder, with some individuals specializing in plundering seabird colonies.

Second year

Early second-year birds have a slaty mantle contrasting with brown-and-white wing coverts. Second-year birds develop a pinkish base to the bill.

Second year

This species is largely restricted to the coast of northeastern Asia, but nonbreeding and wintering birds regularly occur in western Alaska.

In flight

In flight, note the strikingly patterned underwing, with white wing linings, mostly gray flight feathers, broad white trailing edge to inner wing, and black wingtips with white spots.

Third year

Third-year birds are similar to adults, but have some brown on the wings and some black markings on a horn-colored bill. Note the wide white crescents on the back and in front of the black-and-white wingtips.

Third year

In flight, third-year individuals are similar to adults, but note the broad black tail band and brown blotches in the wings. The adult “string of pearls” pattern in the outer flight feathers is often less conspicuous in third-year birds.

See more images of this species in Macaulay Library

Compare with Similar Species

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Great Black-backed Gull

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Identification

Thickset, short-winged, pot-bellied gull. Adult has dark gray back and wings, intense pink legs, and an especially large white “crescent” (white tertial edges) near the wingtips when perched. Breeding adult white-headed; nonbreeding birds have variably heavy brown streaking on the head and upper breast. Takes four years for immatures to progress from mostly brown to fully white and gray adult plumage; intermediate plumages are often mottled and messy. Often looks rather frosty by the first winter; starts to develop a gray back and whitish eye in its second year. Primarily an Asian species, found in coastal regions from Japan and South Korea to Russia. Regularly occurs in western Alaska, but very rare elsewhere in North America.