Barred Owl (Cinereous)
Strix varia sartorii
The same adult bird vocalizing in ML21688921. Presumed male due to pitch of the song.
Photographed and audio recorded. See http://earbirding.com/blog/archives/4905. We returned to where we had found the juvenile the night before, and quickly refound that bird. After watching it and recording it through two feeding events (unseen at the time, but audio recorded and attached below), an adult bird started singing. We obtained various recordings and eventually good photos of that bird.