Robson illustrates the female with a yellow-orange bill, but this bird definitely had an all dark bill as illustrated in HBW. The bird was
actively flycatching. Tail was rusty with barring on the underside. Assuming we identified the bird correctly, the race occurring in Thailand is the nominate.
Digiscoped with Panasonic DMC-LX5 | Nikon FieldScope III | 30XWA |hand-held (no adapter).