My apologies if this is unrelated. The original post has changed, but it seems like you are looking to ward off birds of prey. My wife loves her chickens but sometimes hawks come and kill the chickens. She doesn't like guns, so no air gun for her, but she seems to like using slingshots. So I got her a bowl of dried beans, and she shoots at hawks when they come by. They fly away and dont come back for a while. Dried beans from a slingshot don't do much damage, barely leaves a mark on drywall.
Now with hawks barely coming by, chickens have been safe.. but now we've got a bunch of mice coming by now... maybe hawks were controlling mice population. So I ended up getting an air pistol (Beeman P-17) to kill the mice.. but I have been unsuccessful after days of shooting at them. Shooting at a tiny, fast moving mice seem to be a lot more challenging than stationary target shooting. I like it though. It is incomparably cheaper than .45 ACP, and I can shoot in my backyard.