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Slaty-backed Gull - BirdForum Opus

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Adult
Photo © by Richard B. Stern
Glace Bay, Nova Scotia, Canada, 3 January 2004
Larus schistisagus

Alternative Names: Kamchatka Gull, Pacific Gull.

Identification

L. 27 inches (68.5 cm)

Breeding Adult

  • White head, belly, and tail
  • Dark, slaty-gray back and wings
    • Broad white trailing edge
First cycle
Photo &copy by Ayuwat J
Beppu, Oita, Japan
  • Underside of wings features a "string of pearls" along the edges
    • Can be seen from below when the bird is in flight
  • Yellow eyes
  • Pink legs (appear shorter than similar gulls)
  • Body appears stouter than similar gulls
  • Yellow bill with orange-red subterminal band

Immature

Highly variable. First cycle mostly brown with brownish wing-tips. May have bleached greater coverts. Second cycle similar but with dark slaty-colored mantle feathers. Third cycle similar to adult but with brown smudging on wing coverts and black spots on otherwise white tail.

Similar Species

Second cycle
Photo &copy by Joseph Morlan
Choshi Port, Chiba Prefecture, Japan, 9 February 2019

The wings and back are slightly darker than those of the Western Gull. Slaty-backed usually shows extended secondaries forming a "skirt." Relatively short primary projection and pot-bellied look. Immature is similar to Great Black-backed Gull, but paler; lacks checkered appearance of that species. Usually distinguished from Herring Gull by brown rather than black wing-tips and relatively plain pattern on greater coverts. May be confused with hybrids between Glaucous-winged Gull and either Herring or Western Gull.

Distribution

It is a common coastal breeding species in northeastern Asia, wintering southward to Japan, Korea and China. Frequently wanders to the western Alaska shorelines. Now annual in northeastern North America with records in many states.

Taxonomy

This is a monotypic species[1].

Habitat

Coastal areas.

Behaviour

Diet

Adult
Photo © by Daniel Smith
Akuna, Kagoshima, Japan, 23 January 2009

Forager and a scavenger.

References

  1. Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2018. The eBird/Clements checklist of birds of the world: v2018. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
  2. Avianweb
  3. Burger, J., Gochfeld, M., Garcia, E.F.J. & Kirwan, G.M. (2019). Slaty-backed Gull (Larus schistisagus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/53985 on 15 March 2019).
  4. Howell, S.N.G. & Dunn, J.L. (2007) Gulls of the Americas. Houghton Mifflin, Boston.
  5. Malling Olsen, K. & Larsson, H. (2003) Gulls of Europe, Asia and North America. Christopher Helm, London.

Recommended Citation

External Links

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