I'm going to amend this to unidentified buteo. It might be a Harlans. This bird has long wings, to the end of the tail, and it -appears- to have feathered tarsi. It has the "small billed" look that I associate with rough leg. However, it's much more sooty than any rough leg I've seen and the light parts are not as blonde. Finally, just before I left, it fanned it's tail, and there's a bit of red just above a darker band. I did not see it fly.