A June Mangrove Cuckoo [confirmed by the experts.]

This photo was taken by José Carlos García near the Río Mono bridge in Bayano, sometime in June. The bird was identified as a Mangrove Cuckoo, which, though rare during the boreal summer, has been reported in Central Panama in June. As fas as I know, there are no records of over-summering Yellow-billeds in Panama, and the yellow bill seems to rule out all those southern vagrants, but if you have any better guesses do chime in.