Overrun with chipmunks?  This Spring found us with a startlingly huge increase in chipmunks as it has for many this year. We have had amazing success considerably lowering their population with these simple, humane and environmentally friendly tactics: Clean up all areas around the home and gardens, eliminating their hiding places; leaves, sticks, rocks, etc. and trim plants/bushes away from the home perimeter. We had an old brick barbecue that had become a chipmunk ‘hotel’ so that was also removed. Use Cayenne or similar retardant (pureed garlic &/or hot pepper spray, coffee grounds-ask a local coffee shop for their grounds, etc.) to sprinkle/spray the areas after clean-up. Liquid retardants generally last longer than dry. We have had success with Plantskydd (a blood meal product) available in granular and liquid.  Plant flowers and herbs that are natural deterrents ; some examples are: Marigolds, Ageratum, Shasta, Yarrow, Black Eyed Susan, Phlox, Spider wort Sage, Or...