1st winter
Vega Gulls Larus vegae
February 18th 2006 Choshi Chiba Japan
The darkish gray new scapulars, dark outer greater coverts and mottled belly may suggest 'taimyrensis'.
Slaty-backed Gull Larus schistisagus
for comparison
Note the brownish, shortish primaries and worn tertials and coverts.