Slaty-backed gull


The slaty-backed gull is a large, white-headed gull that breeds on the north-eastern coast of the Palearctic, but travels widely during nonbreeding seasons. It is similar in appearance to the western gull and the glaucous-winged gull. Another alternate name is Pacific gull, though this also applies to a Southern Hemisphere species, L. pacificus. Claims have been made as to its presence throughout North America. as well as the eastern coast of temperate Asia. On 3 November 2012, an individual was spotted in Finland. The species has only been spotted three times before in Europe.
This species is tied with the yellow-footed gull for fourth-largest gull species. This species measures in length, in wingspan, and in weight. Among standard measurements, the wing chord is, the bill is, and the tarsus is. It has a white head, belly, and tail with a dark slaty-gray back and wings with a broad white trailing edge. The wings and back are slightly darker than those of the western gull. The undersides of the wings feature a "string of pearls" pattern along their edges; these can be seen from below when the bird is in flight. Its eyes are yellow. The legs are pink and short when compared with those of similar-looking gulls, and the body appears more stout. The bill is yellow with orange-red subterminal spot. Immature gulls' plumage is brown, similar to that of the great black-backed gull, but paler, and is practically indistinguishable from the immature herring gull in the field.

Etymology

The genus name is from Latin larus, which appears to have referred to a gull or other large seabird. The specific schistisagus is from New Latin schistus, "slate", and Latin sagus, "cloak".