Claudia's leaf warbler 
(Phylloscopus claudiae)

Claudia's leaf warbler (Phylloscopus claudiae) belongs to the leaf warbler family Phylloscopidae found only in China and Vietnam.
The birds was previously considered a subspecies of the Blyth's leaf warbler.

The name Phylloscopus combines the Ancient Greek phullon meaning "leaf" and skopos meaning "seeker" (from skopeo, "to watch").