Mar 12th 2012
Choshi Chiba Japan
Gulls generally have broad tail band, and often show a all-dark tail
like Western Gull. But actually many birds have variable amounts of
white on their outer tail feathers. Their overall coloration looks less
contrasty than Vega Gull, but on the other hand usually gives a patchy, uneven
impression compared to Thayer's and Glaucous-winged Gulls.
This individual shows relatively
strong contrast between dark wingtips/tail-band and other parts, so overall
pattern in flight resembles Vega Gull. But its overall impression in the field
was Slaty-backed Gull.
as a variation of Slaty-backd Gull. But looks rather hard to distinguish from
Vega Gull in this photo.