I do not think that this is a Masked Wood swallow. The mask is too extensive above the eye, the beak is not curved or white/grey with a black tip. The feather pattern of the wings is wrong and the bird has a white tail tip. This all adds up to a Black Faced Cuckoo Shrike. Would you please re-think your diagnosis and amend it or communicate with me. Nevertheless the photo is superb to show all the identification features of the bird.