Wanted: Field guide to birds of Southeast Asia

I was stopping off at a waterfall on the road to Tham Lod (to see a few hundred thousand Pacific swifts funnel into a giant cave to roost for the night) when I came upon this rotund little bird. It was hopping and fluttering around from rock to rock at the base of a series of rapids, apparently catching bugs lurking near the surface of the water.

 Mae Hong Son province, Thailand

Mae Hong Son province, Thailand

I'm very sad (very, very sad) to say that I don't have a field guide with me at the moment. The internet is fickle in these parts, but next time I get decent wifi I'll start by perusing the Muscicapidae (if I'm on the wrong track, somebody set me straight.)