White-tailed Leaf Warbler or Davison's leaf warbler 
(Chích Davison, Phylloscopus intensior or Phylloscopus davisoni)

Davison's leaf warbler (Phylloscopus intensior) or the white-tailed leaf warbler, is a species of leaf warbler (family Phylloscopidae).
The bird  is found in the China, Laos, Myanmar, Thailand, and Vietnam.

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").
intensior Latin intensior more intense (from intensus intense).