Mongolian Gull Larus (?) mongolicus
February 3rd 2007 Choshi Chiba Japan

This very typical Mongolian Gull seemed to be larger and longer-billed than this individual found on January 19th, and had 8 black-marked primaries. Its almost completely white head was shining among Vega Gulls, and the longish overall structure was also typical for this form.

Note the clean white head and longish bill-body-primaries. Some faint streaks were barely visible on hindneck.

The primary projection often looked quite long.

Note the pale flesh legs.

Note the long-winged silhouette. The P4 has black spots on both outer and inner webs. The 8th black spot on P3 is unusual in Vega Gulls. The upperparts seemed slightly paler than Vega Gulls.

The bright yellow bill of the Mongolian Gull has black spots on both upper and lower mandible. The red spot seems to be isolated from the upper edge of lower mandible. These characteristics can be shared with Vega Gulls, and also can be variable in Mongolian Gulls. But at least it finely matches up with many Mongolian Gulls photographed in Korea, or descriptions for Mongolian Gulls in breeding grounds. The iris is moderatly dark, and the orbital ring is red.

Compared to Vega Gulls, Mongolian Gulls tend to show obviously long-winged impression in flight, though of course it can be strongly influenced by momentary wing/body angles and the like.