When I looked more closely with my spotting scope at this Zone-tailed Hawk at El Zacatel, I could see it was in juvenal plumage. The bottom pic shows the tail up close so the dark irregular bands on the dorsal (upper) surface are visible. And on the far left of the tail feathers is one tail feather showing the ventral (lower) surface that whitish with dark black bands (only 2 visible). Note the 2 wingtips that are showing below the tail feathers, another feature of this species is their wings being very long. Also note the jaggedness of the tail feathers--I also saw this on the juvenile I followed as it perched and roosted at Frontera Audubon. I suspect this is the same juvenile bird because this location is less than 10 miles from Frontera, well within range for foraging for such raptors, and the ragged tail feathers would be consistent. The bottom pic (head is turned away from camera so viewing back of head) shows white on it's head, lots of white showing because the ...