Well, come to think of it, regarding the squirrel problem, I do have a bow - Osagebowman showed me how to make it - that shoots subsonic rounds, and damned accurately. And fairly silently.
Some of those "nutter" arrows that I've read about may be just the ticket, what do you think, Osage?
Absolutely, 'nutters' work fine, they deliver a good hit, easy to make and you can experiment to find the right combination for your particular situation.
Empty .38 brass, with two or three bb sized shot for weight works well too.
A judo type head helps prevent losing arrows in tall/thick vegetation.
Some have used a small broadhead bleeder blade and a blunt for real 'series' small game head.