This is primarily a montane species reaching Thailand only in winter when it occurs regularly in the northern part of the country. It is not common at Khao Yai and we only encountered it once on our visit. This is an adult of the widespread nominate race. A smaller, paler race with a white wing patch occurs in the western Himalayas where it is largely resident. The English name is often spelled "Grey-backed Shrike" following British usage.
Digiscoped with Panasonic DMC-LX5 | Nikon FieldScope III | 30XWA |hand-held (no adapter).