At first I thought this might be a Red-Shouldered Hawk, but now I think it looks more like a Ferruginous Hawk. It had just finished feasting on a nest of baby robins when I took the photo. It was still hungry and looking for something else on the ground. Look at those talons! I had tried to help the robins by throwing a whisk broom (what I happened to have in my hand at the time) up at the hawk, and I almost hit it a couple times. I'm sort of glad I didn't because it wouldn't be too wise to tangle with that bird. Later, I read up on hawks and learned that alot of them have a hard time making a go of it, and often starve in the winter, whereas robins, of course, are plentiful. A Ferruginous Hawk, if that is what this is, is one of the largest hawks in North America, with a wingspan of up to six feet.
Here is video of the hawk, if anyone's interested.
http://s1355.photobucket.com/user/Daylilies-Flowers-Animals/media/Animals/2013-7-7Hawk_zps2ae9e568.mp4.html?filters[user]=132771370&filters[recent]=1&filters[publicOnly]=1&sort=1&o=0