Buff-Thoated Warbler 
(Chích bụng hung, Phylloscopus subaffinis)

The buff-throated warbler (Phylloscopus subaffinis) is a species of leaf warbler (family Phylloscopidae).
The bird breeds in China and winters down toward northern Southeast Asia.

The name Phylloscopus combines the Ancient Greek phullon meaning "leaf" and skopos meaning "seeker" (from skopeo, "to watch").
The specific epithet affinis is from Latin meaning "related" or "allied"; subaffinis: slightly, somewhat.