Moulting from adult summer to winter
Heuglin's Gull 
Larus heuglini taimyrensis (or taimyrensis/birulai intergrade)
Tamagawa-river, Kawasaki, Kanagawa, Japan,
October 6th 2000.

Note the upperparts darker gray  than vegae, yellowish legs, shorter bill with large
orange- red spot(extending to upper mandible), large black subterminal band on P10.

Small one mirror on P10.

taimyrensis ( right), vegae ( left).