Kumlien's Iceland Gull (or x Thayer's Gull?) Larus glaucoides kumlieni (or X L.thayeri?)
Mar. 29th 2013 Tokyo Imperial Palace, Japan
This is the same individual as this one on March 22nd.
Note the quite small head and bill compared to the surrounding Vega Gulls.
An encounter with an adult Thayer's Gull.
Note the large, diffuse mirror on P10.
The strong venetian blind is restricted to the outer 4 primaries.