The Brown Shrike (Lanius cristatus) is a bird in the shrike family that is found in Asia.
Like most other shrikes, it has a distinctive black "bandit-mask" through the eye and is found mainly in open scrub habitats, where it perches on the tops of thorny bushes in search of prey.
Females have fine scalloping on the underside and the mask is dark brown and not as well marked as in the male. 
Juveniles are more whitish or grayish below, with heavy barring on sides and flanks.
There are 4 subspecies which differ in plumage being slightly darker brown, more reddish in the tail or with or without a grey crown.
The 1-3 photos show a juvenile from the subspecies Lanius cristatus lucionensis which has a grey crown.
The last photo shows a female of the subspecies Lanius cristatus lucionensis.

1st, 2nd & 3rd photo: Khao Yai National Park, Thailand, 30 December 2009
4th photo: Khao Sok National Park area, Surat Thani Province, Thailand, 25 January 2013