Something new to me! Seems the Peregrine Falcon is aka historically as the Duck Hawk in North America or Bullet Hawk.
Both nests and (less frequently) adults are predated by larger-bodied raptorial birds like eagles, large owls, or Gyrfalcons. Peregrines defending their nests have managed to kill raptors as large as Golden Eagles and Bald Eagles (which they normally avoid) that have come close to the nest.
Ok, after reading the article above I went in search of more info on falcons going after Bald Eagles and Golden Eagles. I found this. WOW! They are fearless!