Mongolian Gull L.(?) mongolicus
January 24th 2003 Choshi Chiba Japan

This individual has really nice characteristics to be a Mongolian Gull, especially 8 black-marked primaries, black-marked long bill, and general structure. But its rich winter mottling around the neck might be unusual.

Note the powerfully-built body. The deep chest seems to hint the neck is long.

The Mongolian Gull with 2 Vega Gulls
Note their bill/head structures.

A Vega Gull (left), and the Mongolian Gull (right).
The red gonydeal spot of the Mongolian Gull does not reach upper edge of lower mandible.

The wing has 8 black-marked primaries. And the pattern of the underside P10 differs from Caspian Gulls.

Caspian Gull on the same day.