What can I do to get rid of voles? also chipmonks?
Voles and chipmunks are pests that aggravate a broad array of gardeners and farmers as they can damage field crops, root crops, orchards and perennial beds. However, the life cycle and habits of the two are different enough to warrant separate approaches to their management.
Elimination is nearly impossible for voles. Also known as field mice or meadow mice, there simply are too many of them. They are active year round, day and night. They do not hibernate and reproduce prolifically. The best to hope for with these rodents is control.
Voles have a wide palate, although they prefer grasses and forbs, along with bark and field crops when populations are high. They have been known to eat flesh and to scavenge, eating snails, insects and animal remains. It is unlikely you will eliminate a food source.
When protecting orchard stock, bury hardware cloth about 6" deep around small trees and shrubs to prevent the girdling damage voles can do to root systems. It is usually not effective to fence in an entire orchard but can be possible with individual trees.
Keep your lawn mowed regularly and clear away yard debris, eliminating the ground cover they need for protection. Wood piles, leaf litter are all good places for voles to hide and build nests.
It is best to talk with local wildlife professionals about the best way to use poison and repellants to control voles. It is important, when using poisons, to be sure the poison cannot be eaten by ground feeding birds, other wildlife or small children. The key is to place baited traps in areas that other critters cannot reach. Repellants that use capsaicin, the "hot" in peppers, may provide some short-term relief although research does not speak to that issue.
As for chipmunks, these territorial burrowing rodents do most of their damage by building their extensive network of tunnels near foundations or under other structures, weakening them.
It is best to keep the food they prefer such as nuts, grains, berries and seeds away from structures so that their burrows do not damage buildings, deck foundations and other outdoor amenities. They reproduce once, rarely twice a year and range over a 1/2 acre. Territories sometimes overlap but not by much.
To prevent damage to ornamentals, exclusion is the best policy, wrapping vulnerable plant material such as bulbs and tubers in hardware cloth and burying the entire assemblage under the soil. It can be time consuming, but so is replacing precious bulbs year after year.
While there are repellants and poisons that can be used, they are not as effective or practical as trapping, either in live traps or using snap traps. If you use live traps, "pre-bait" the traps with things such as peanut butter, nut balls and other items and wire the trap door open for a few days to make the chipmunk think it has found a new reliable food source. Once you go live with the trap, check it often to deal with the chipmunks and with other, non-target wildlife that may have gotten trapped inadvertently.
If you decide to use a snap trap, do the same "pre-baiting." Be sure to put the traps where they will not capture small birds, possibly by locating them under a board or inside a box with holes on each end only large enough for the chipmunk.
It does not appear that either voles or chipmunks are protected, but it is always wise to check with wildlife professionals to be sure and to find out from them the best, most effective way to control these landscape pests.