Thanks for the input! Well, since my experts disagree, I've been trying to do more research at home. At this point I'm inclined to agree with Yellow-bellied, but always happy to hear more comments. From what I've read it sounds like there is too much yellow on this bird for a Least. Although a Least can have a bit of yellow on the lower belly and flanks, it should have a white throat. Also, the beak looks a bit long for a Least but maybe that's too subjective. The overall small size, roundish head and shortish tail rule out any other candidates.
-kris
