A cat or two, yours or a neighbors, definitely helps. Another option is to trap them. Mouse traps are too small. PIck the next size up or a rat treap. Peanut butter is a good bait (until ants find it). One of my neighbors has a grisly but effective trick. She starts with one of those 5-gal plastic buckets, fills it with water about three-quarters full, then covers the surface of the water with sunflower seeds (still in their hulls so they float). Then she props a board against the bucket so the chipmunks, attracted by the smell of the seeds, can run up the board and look in the bucket. They see the seeds, they jump in, they drown. I said it was grisly.