About 9 AM this morning while driving through an intersection between Fort Collins and Windsor, just east of where Harmony Rd crosses I25, I saw what I would describe as a hawk, certainly a raptor, approximately raven-sized. I saw it fly upwards from near ground and perch on a light standard in bright sun, so I got a brief view of both the underside as well as of side,back and legs. My very first thought was that it was a Swainson's but it was too small. I actually stopped for 3-4 seconds in the intersection to observe it but had to leave to keep from blocking traffic.
While it flew, I believe I saw an un-banded tail underside, the back half dark with the front part lighter. When it perched I could see that the back, sides and tail were generally brownish with only a little variation. The under-wings were also bi-color, with perhaps 30% dark on the leading edge and the rest lighter with maybe a little checkering, though I'm not very sure of this.
What stood out to me was that as I looked at it perched the legs were *red*. Not just the feet either, on up for 2-3 inches where they were lost in body feathers. I regret that I couldn't take a picture because I was in the middle of the intersection and couldn't quickly get a shot.
As I'm no more than an average birder without good observational skills and relatively new to Colorado I thought "I'll look when I get home to see what it could have been" but upon coming home and looking, nothing makes sense. I have seen several species of hawks and falcons in western states, including various juveniles and morphs but nothing I can remember that has red legs.