Black-tailed Gull (crassirostris) / ウミネコ / 괭이갈매기

(last update: December 2015)

Kim Seog-min (South Korea)
Hideo Shimura (Japan)
Peter Adriaens (Belgium)
Mars Muusse (Netherlands)

Black-tailed Gull (crassirostris) adult, May 03 2015, Hachinohe-shi, Aomori Prefecture, Japan. Picture: GenJapan.

Please visit GenJapan's photostream on Flickr.

Note dark centres on primary coverts, which is probably present in true adults as well (hence in general probably no safe indication for immaturity, but shape and bordering of black centres may still be of value).