Not an unusual bird, but my best shot yet of a Red-tail, so here it is!

This is a classic adult "Eastern" (subspecies borealis) Red-tail. This bird has the tail unbanded except for a narrow black subterminal band. Western birds (calarus) typically show other banding on the tail as well. The wingtips fall well short of the tail tip on Eastern birds, reach the tail on Westerns (this can be subjective to the way the bird is sitting). There is a large, whitish mottled area on the scapulars, more extensive than usually shown by Westerns. The throat is obviously white on this bird, dark on Westerns.

Unfortunately you don't usually get quite this good a look at light-morph Western to compare this easily. Winter Red-tails are one of my favorite groups of birds. It's not too hard to see 4 or 5 different morphs/subspecies in west TN during a winter day, especially along the Mississippi.