Black-capped Donacobius (Donacobius atricapilla)

As I was slowly moving on the river of Fazenda San Francisco I noticed this bird in a dense thicket on the riverside.

What’s peculiar is the white on its head, which should normally be all black, as well as having a bright and yellow iris.

Black-capped Donacobius (Donacobius atricapilla)
One possibility is that this is the supspecies albovittatus, the other is that this is a juvenile. Evidently the juveniles of southwestern Brazil temporarily have the white streaks on the head as well as a brown iris..

Thanks to contributors for clarifications.

It sounds like this:

Last updated on 7 December 2020