Large owls are bigger than you think. As a person well versed in great horned owl (in particular) vs cat (homeless roaming), I've seen adult cats with 9mm (think of a 9mm bullet size) nearly perfectly round deep punctures in their head from owl attacks. I assume the owl grabs the cat but is unable to successfully carry it off. Additionally, owls that attack kittens like to tear their chest open and eat them alive. Nothing like fnding a kitten torn open on your driveway or deck.