stunned baby hawk
We think it's a Cooper's Hawk, with Sharp-Shinned a possibility as well. It hit the window with an almighty bang and the deck with an audible plop. It rested like this for a long while, perhaps an hour, before sitting up. The poor thing had to endure rain and then hail before it flew off at dusk.
Picture taken through a window as we didn't want to disturb him by going outside.