I've had a medium sized bird (~16-18"long) hanging around the house today, but I haven't been able to get a good profile view (or pictures). The closest thing in my bird book is a Sharp-Shinned Hawk, yet the size seems bigger than the book's description [10-14"length]. It has grey and black horizontal bars on the back of its tail-feathers, with a slight white margin separating them. The two times it flew by the window I've been sitting in front of- my first impression was one of an owl, but then I had a good long look at the back of its body as it perched on an aspen branch behind the house. It took off and headed for the ground back in the woods. There are lots of rabbits around (and some squirrel)- It may be feeding on a kill. Any thoughts?