Slaty-backed Gull Similar Species Comparison
Main SpeciesSlaty-backed Gull
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.
© Ian Davies / Macaulay LibraryAlaska, May 22, 2013Nonbreeding 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.
© Ian Davies / Macaulay LibraryHokkaido, December 26, 2013Nonbreeding 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.
© Joel Strong / Macaulay LibraryNew York, December 26, 2020First 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.
© Ian Davies / Macaulay LibraryHokkaido, December 27, 2013First year
First-winter birds can look pale and bleached.
© Pam Rasmussen / Macaulay LibraryHokkaido, March 14, 2015Breeding adult
An opportunistic, omnivorous feeder, with some individuals specializing in plundering seabird colonies.
© Jian-Long(建龍) WU(吳) / Macaulay LibraryHokkaido, June 20, 2024Second 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.
© Blake Matheson / Macaulay LibraryCalifornia, February 06, 2018Second year
This species is largely restricted to the coast of northeastern Asia, but nonbreeding and wintering birds regularly occur in western Alaska.
© Markus Deutsch / Macaulay LibraryAlaska, June 18, 2009In 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.
© Josep del Hoyo / Macaulay LibraryHokkaido, February 06, 2010Third 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.
© Nick Hajdukovich / Macaulay LibraryAlaska, January 17, 2011Third 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.
© Ian Davies / Macaulay LibraryHokkaido, December 26, 2013Similar SpeciesVega Gull
Breeding adult
Adult Vega Gull has paler gray upperparts than adult Slaty-backed Gull. Second- and third-year Vega Gulls also have a paler mantle than similarly aged Slaty-backed Gulls.
© Ian Davies / Macaulay LibraryAlaska, May 22, 2013Similar SpeciesVega Gull
First year
Vega Gull is slightly smaller and lighter weight than Slaty-backed Gull, with a thinner bill and longer wingtips. First-winter Vega Gull has more strongly patterned upperparts than first-winter Slaty-backed Gull, with blackish (rather than brownish) wingtips.
© Ian Davies / Macaulay LibraryHokkaido, December 27, 2013Similar SpeciesGlaucous-winged Gull
Breeding adult
Adult Glaucous-winged Gull has lighter gray upperparts than Slaty-backed Gull, with mostly gray wingtips (versus black in Slaty-backed Gull).
© Timo Mitzen / Macaulay LibraryCalifornia, February 26, 2020Similar SpeciesGlaucous-winged Gull
First year
First-year Glaucous-winged Gull has grayish wingtips and lacks the heavy head streaking and dark eye mask of first year Slaty-backed Gull.
© Christoph Moning / Macaulay LibraryHokkaido, February 20, 2017Similar SpeciesWestern Gull
Nonbreeding adult
Western Gull and Slaty-backed Gull ranges don’t normally overlap. Adult Western Gull has slightly lighter upperparts than Slaty-backed Gull and a more bulbous bill. Nonbreeding adult Western Gull lacks the heavy head streaking found on nonbreeding adult Slaty-backed Gull.
© Mason Maron / Macaulay LibraryCalifornia, January 14, 2021Similar SpeciesWestern Gull
Breeding adult
In flight, adult Western Gull has less white in the wingtips than Slaty-backed Gull, and on the underwing, darker primaries.
© Aidan Brubaker / Macaulay LibraryCalifornia, July 05, 2021Similar SpeciesGreat Black-backed Gull
Nonbreeding adult
Great Black-backed Gull and Slaty-backed Gull ranges don’t normally overlap. Adult Great Black-backed Gull is larger than Slaty-backed Gull, with darker upperparts, a heavier bill, and paler pink legs. Nonbreeding adult Great Black-backed Gull has at most very limited streaking on the head, as opposed to the heavy streaking found on nonbreeding adult Slaty-backed Gull.
© Jean Iron / Macaulay LibraryOntario, December 27, 2020Compare with Similar Species
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Species in This Family
Gulls, Terns, and Skimmers(Order: Charadriiformes, Family: Laridae)
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