Sakhalin Leaf Warbler 
(Chích lá Sakhalin, Phylloscopus borealoides)

The Sakhalin leaf warbler (Phylloscopus borealoides) is a species of Old World warbler in the family Phylloscopidae. 
The bird is found in Sakhalin, the Kuril Islands and Japan; it winters to the Amami and Okinawa islands and Indochina.

Leaf warblers are small insectivorous passerine birds belonging to the genus Phylloscopus. 
Leaf warblers were formerly included in the Old World warbler family but are now considered to belong to the family Phylloscopidae, introduced in 2006.
The name Phylloscopus combines the Ancient Greek phullon meaning "leaf" and skopos meaning "seeker" (from skopeo, "to watch").