There's a chipmunk trap described on another list. It consists of a 5-gallon bucket, half full of water, with sunflower seeds sprinkled on top of the water. Then they lay a 3 inch wide plank (2x4 or a roofing shingle)from a step or something to the rim of the bucket. Then seed the trap with a few sunflower seeds on top of the plank. That's all. Then go about your business. The writer reported catching 15 chipmunks in a few days. Too bad they can't tread water very long. Then if you're the sensitive type, you can relocate the catch to another place where they can have a full and complete life. I would relocate them to the bottom of my compost pile.
I think the same trap would work for rats, mice, and squirrels. You might have to modify the bait and the bucket, but why not. For squirrels you might have to go with a deep Rubbermaid bin, say 18-gallons. Sunflower seeds might work for all these pests.