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

(last update: December 2015)

Slaty-backed Gull (schistisagus) 3rd cycle (3CY), September 16 2009, Hokkaido, Japan. Picture: Hannu Huhtinen.

Active complete moult, moulting to 3rd cycle. P1-P8 replaced for adult-like 3rd gen primaries. Limited, but obvious black on bill, pale iris and extensive winter head streaking running down over the underparts to the legs. New 3rd gen tail-feathers with limited black.