Sentence:  Instantly the keen-eyed hawk "stooped," or descended, with a rushing swoop, and struck one of the birds with her claws, but without killing it, which is called "rifling," or "<WSD>ruffing</WSD>" it. 
Meaning of the word marked with <WSD> tags:  Of a falcon, hawk, etc.: to hit (the prey) without fixing or grabbing hold of it.