Thanks to Sanctuary Friend Hank Giles for these great pictures of a Cooper’s Hawk that was in his back yard (Charlton, MA)!
It turns out that the Cooper’s Hawk is no longer “uncommon” in Mass due to improved breeding conditions. The Sharp-shinned Hawk looks very similar to Cooper’s, but has smaller head and does not have a white tip on the tail. The Sharp-shinned is less common than the Cooper’s.