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

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.)