This small shrike is highly migratory, occurring in Thailand only in the non-breeding season. Males and females are similar but females average less white across the forehead and above the mask. This individual has the white much reduced as expected in females. It also lacks the barring on the underparts of immatures, so I feel comfortable that it shows characters suggesting adult female.
There are four subspecies, two of which winter regularly in Thailand. Based on published ranges, this is the nominate race. The similar L. c. confusus winters further south and is said to have a wider white frontal patch.
Digiscoped with Panasonic DMC-LX5 | Nikon FieldScope III | 30XWA |hand-held (no adapter).