Slaty-backed Gull Larus schistisagus
Shinobazuike-pond Ueno Tokyo Japan, February 20 2001

Mantle color of slaty-backed gull sometimes looks
not so dark by some variation or light condition.
Adult winter to summer, female-type, 
rather darker mantled individual.
with adult winter vega gull.

Generally slaty-backed gulls acquire white head
earlier than vega gulls.
But many individual still had head streaking on this day.
See also this page.


4th(?) winter to summer.