Slaty-backed Gull (schistisagus) / オオセグロカモメ / 큰재갈매기

(last update: December 2015)

Slaty-backed Gull (schistisagus) 1st cycle, December 27 2009 - January 04 2010, Choshi, Japan. Picture: Chris Gibbins.

See Chris's BLOG.

Bulky bird. The key features are the smithsonianus-like rump and tail pattern (wholly dark tail and a well barred rump and upper tail coverts), the rather uniform primaries (with none of the strong patterning (spots, bars) so evident in P1-5 of Vega and Herring Gulls of this age) and the uniform panel formed by the greater coverts. Plain tertials and simply patterned second generation scapulars (with dark shaft streaks rather than cross-bars, and often greyish in tone). The underwing coverts are very uniform, softly patterned with brown.