Slaty-backed Gull (schistisagus) / オオセグロカモメ / 큰재갈매기
(last update: December 2015)
Slaty-backed Gull (schistisagus) 4th cycle / 4CY October
Identification of this age class is difficult. Birds are supposed to be in 4CY plumage when they combine two aspects; a. new flight feathers are adult-like, without immature markings, and b. old flight feathers, which are (heavily) worn, are old 3rd gen feathers (adult-like patterns, like bold white tips on old secondaries, limited black in tail and P10 sometimes with distinct mirror).
|Slaty-backed Gull (schistisagus) hybrid? 4th cycle (4CY), October 17 2009, Tsuri-shihama, Japan. Picture: Shigenobu Aizawa.|
|Slaty-backed Gull (schistisagus) 4th cycle (4CY), October 02 2007, Isohama, Tsuri-shihama, Japan. Picture: Shigenobu Aizawa.|