Heuglin's GullLarus heuglini taimyrensis
Choshi, Chiba, Japan, April 7th 2001.

Some taimyrensis  often look similar to atlantis or graellisii , 
but usually have streaking mainly on hindneck, rather than face.
I guess atlantis or graellisii often  have more streaking around eyes rather than hindneck in fall to mid-winter
and usually acquire pure white head in earlier season than taimyrensis.
This has orange-yellow legs.
This image shows pinkish-toned legs, 
but it was yellower than vegae in the field.

Third winter to summer.
Taimyrensis often shows small bill like this 
compared with most vegae.