mid-13c., preie, "animal hunted for food, that which is seized by any carnivorous animal to be devoured" (slo figurative, of souls captured by Satan, etc.), also "goods taken in war," from Old French preie "booty, animal taken in the chase" (mid-12c., Modern French proie), from Latin praeda "booty, plunder; game hunted."
This is from earlier praeheda, literally "something seized before," from PIE *prai-heda-; for the first element see prae-; the second element is related to the second element in prehendere "to grasp, seize," from PIE root *ghend- "to seize, to take."
The meaning "act of preying or seizing upon anything" is from early 14c.; bird of prey is from late 14c. (fowl of prey is mid-14c.).
c. 1300, "to plunder, pillage, ravage," from prey (n.) and in part from Old French preer, earlier preder (c.1040), from Late Latin praedare, collateral form of Latin praedari "to take booty, plunder, pillage; catch animals as game," from praeda "booty, plunder; game hunted." Its sense of "to kill and devour" (an animal) is attested in English from mid-14c. Related: Preyed; preyer; preying.