My storage location has an "automatic mouse killing system" ... One of the tenants feeds about 9 cats 3 or 4 days a week. Enough to keep them around, and little enough to keep them hunting for mice. They also keep the bird population off my PC.
When we first got married, we lived frugally in the back half of the main floor of a VERY old 5 unit converted house. The neighbor next door fed alley cats so they were everywhere. That introduced a problem of a different kind. There needs to be a "balance of nature" that is difficult to define and maintain.
I have terminated 5 (correction...7 as of this morning) chipmunks around my house in the past 4 days using the
JAWZ trap bated with peanut butter. The smaller mice enjoy the treat without activating it, hence the sticky pads.
I think I wiped out the mouse threat in enclosed spaces like the garage and shed, now focused outdoors around the house. Chipmunks, mice, squirrels, it's all the same problem. They get into things and do damage.
Squirrels are smarter, not sure how to get them. A cheap Daisy BB rifle has no aim beyond 20 feet, making a kill nearly impossible. You need to attract them to get them close enough for a shot which in itself defeats the purpose by having them hang around close to the house. I could buy a better rifle that shoots pointed BBs for a clean shot from afar, but as many here know me, I am such a miser.
I would try automotive anti-freeze (ethylene glycol) but I don't want to kill other creatures that we live in harmony with.
We let the rodents have their way for far too long that it has become a serious problem around our house, so much that even Irene is on-board with this unfortunate measure of action.