Just a heads up if you're near Camp Verde: I was driving south on I-17 today and saw a hawk perched on the first light pole at the Middle Verde/Cliff Castle Casino exit. It was almost pure white underneath and on the head and looked like it had a bit of a dark line at the eye. I turned around but couldn't get very close to it. From the back I decided it was just a Red-tailed hawk with a pigment issue--brownish back speckled with white and a white head. Looking at Sibley and some online photos tonight, it seems like it might have been a light morph Harlan's or a Krider's.