Thayer's Gull Larus thayeri
March 25th 2005 Choshi Chiba Japan
All photos in this page capture 1 adult Thayer's Gull.

A Thayer's Gull in front of the flock of Vega Gull including some Black-tailed Gulls and 1 Glaucous Gull

Interestingly, this seems to be the same individual as this 3rd winter bird on January 7th 2003.