Raptor?

On November 20th just before dusk, this bird was flying around the house. I snapped this picture in the backyard.

The next morning around dawn I saw what I think was the same bird in another area of our backyard. He was eating something sitting in a big pile of something white. He would perch in the nearby tree, then go down to the ground and pecked around in this spot and back up inthe tree.

A while later I went out to see what the 'white pile' was and it was the remains of a bird. Not really anything left but feathers.

I'm not sure what kind of bird this is. I thought maybe a harrier or a falcon.