The air rifle would work pretty well I'd say, depending on the situation with neighbours of course. I know someone who was expert with a slingshot (not myself unfortunately) and he'd knock then on the head with a ball bearing which was pretty effective and silent.
Best not to alert those State troopers by firing some rifles or shotguns in your backyard. ☺️
I have thought about getting a slingshot. I think that would be pretty cool and very primal to learn and master. I was watching videos of an Asian lady the other day who was knocking hornet nests out of trees with her slingshot.
I'm reasonable with a slingshot (but not great) and enjoy it a lot. It's an excellent option for cost, knockdown (or pain infliction for humans) and it's silent which could be good in certain situations. Well worth a few bucks to have one I think.
All great reasons to consider it!