It is hard to believe that such little creatures can cause so much damage. First, they leave raised tunnels in your yard that are not unsightly but also make it hard to mow. They eat root crops out of your garden space along with bulbs. When they get into the root system of trees and shrubs they can cause the plant to lean and/or cause dieback that can lead to plant death.
While there are deadly techniques that can be used to get rid of voles, I do not recommend going this route. Traps and poison will kill the voles temporarily and in many situations require one to handle not only the poison but also the dead animal. Instead of choosing a route that will not discourage voles, why not utilize techniques that first do not invite them into to your garden space and second persuade them to leave.
Keep the Garden Clean
Voles like to tunnel in areas that have thick growth. This can occur in gardens that are covered with weeds or in the landscaping where mulch and/or ground covers are thick. To keep the voles from invading these spaces, make sure that weeds have been removed from the garden. Also, make sure that the mulch is not overly deep. While 3 to 5 inches of mulch is required for proper weed control, the more the better is not a philosophy that works in the landscape. Also, make sure that the mulch is not put up too high on to tree trunks.
Create a Barrier
Blocking voles way into a garden space is another technique one can use. But if you choose this technique, be prepared for a lot of work. To use this technique, one will first need to dig a trench all the way around their garden space that is 30 inches deep. Once the trench has been dug, measure off a piece of hardware cloth that is the length of the trench and 36 inches tall. Place the hardware cloth in the trench and fill in with soil. At this point you may notice that you have 5 ot 6 inches sticking up out of the ground. Do not fret. You did measure the space correctly. This excess is required and provides additional vole control.
Scare them Away
Lastly, consider giving your voles a welcome home gift of used cat litter. The smell of the litter will create the illusion that a cat is around and they will avoid the area. If you decide to use this approach, make sure to remove the solid waste from the cat litter and do not just sprinkle the litter on top of the soil. Instead, dig into the tunnel and sprinkle it down into the tunnel. Cover dug tunnel area up. Doing this simple step will prevent other cats from coming and using the used cat litter.