Unknown bird of prey

I saw this raptor perched in a tree on my way to visit a friend and dismissed it as a chimango (common as muck around here). He was still there on the way back a couple of hours later and this time I wasn't so sure so I stopped to take a registration shot (see above). I've taken advice and I'm reliably informed that it's a 'subadulto de gavilán mixto (Parabuteo unicinctus)', which translated means a young Harris (Bay winged) hawk. Nice bird, and I'm glad I stopped.