For three years we have been attacked by cardinals -- the car in the drive, its side view mirrors scratched, paint scratched, they even pulled the rubber stripping off the door -- the garage windows and back windows regularly smacked, coated in slime and peck marks -- and they did the same to my neighbor, even breaking one of his windows. It got to be so constant, and the striking of the house so annoying that I took to harassing them with pellet guns. That reduced some of it but it made other attacks more annoying. I tried pictures of owls, stickers on windows, and was told that an owl statue fails.
But, at PetsMart I saw this, a plushy furry owl in The Martha Stewart Gentle Play collection in the dog toy aisle. I put two in the trees out front... and the cardinals stopped. Stopped.