|January. Japan. |
Age: The mottled brown upperparts with pointed primary tips are typical of a1st cycle, large four-year gull. This crisp individual with mostly fresh uppperparts, has retained a fair number of juvenile scapulars.
Identification: There are many species that come to mind given this overall plumage aspect. The pale rump and uppertail coverts, with defined tailband, immediately call to mind an old world Herring Gull. Given the location, it makes most sense to begin with Vega Gull. Although tail patterns are highly variable in this taxon, the prominent white seen on the outer edge of the outermost tail feathers is a "classic" look expected on 1st cycle Vega. Further, the rather uniform wing panel, with greater coverts largely checkered also supports Vega. In North America, eliminating smithsoninaus would be managable with a concise set of photos, but eliminating argentatus would be more problematic given the overlap in tail patterns. It suffices to recognize such birds as being "off" for American Herring Gull.