http://www.uglyhedgehog.com/t-209253-1.html links to ten months ago, 50 yards away with a discussion of your very question. I ended up guessing Red-shouldered Hawk, but I do not know my birds that well.
Based on the size of the remains found, I believe this to be one of the chicks, which saddens me greatly. Last week I was walking one of my dogs in the woods and we found this.