Vexing Voles

How to Identify and (try to) Control Them

By Jaqueline Merrill, Master Gardener Volunteer

Photos by Under the Same Moon, via Flickr under CC lic., Vole Damage, Brenda Lucas, Bugwood.org, Vole Run, David Clement, U. og MD, Bugwood.org

Voles feed voraciously on perennial roots, ornamental grasses, and tree bark. Chances they are active in your garden now! Who are they and what can you do about them?

Description and Identification

The meadow vole (Microtus pennsylvanicus), sometimes called the field mouse, is a common and prolific mammal with a range that extends throughout North America. The adult is 6 to 8 inches in length (including tail). The fur is solid gray or brown with paler underparts. Voles are vegetarians. They travel via runways in grass or via elaborate subsurface burrows. Moles and shrews also tunnel through grass but eat grubs and insects—not plant matter. Compared to common mice, voles have a short snout, small flat ears, and a much shorter tail. They may burrow around foundations of sheds or outbuildings but rarely are found inside the house

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Habits and Damage

Voles are a vexing and costly pest for gardeners, farmers, and landscapers. They emerge above ground through burrow holes about 1 inch in diameter often hidden under leaf debris. Their burrows or runs, are close to the surface and the ground above them feels soft and spongy. Voles do not hibernate; they are active year-round. They breed all year and may produce up to five litters of six offspring with a lifespan of 2 to 16 months

Voles eat roots, stems, bark, bulbs, tubers, grasses, and the growth of herbaceous plants and may eat up to 100 percent of their body weight in a day. In the garden voles can entirely eat away roots resulting in collapsed, yellowing, or wilting plants, and crop failure. They can cause extensive damage by girdling (chewing around) seedlings, shrubs and when food is scarce in fall and winter, even mature trees. They create surface runs under snow that leave bare trails in grass in spring. Populations peak every 3 to 5 years—areas with no previous damage can suddenly show severe damage

Preventing Vole Damage

Vole damage can be mitigated via habitat modification, fencing/exclusion, repellants, and trapping. A less suitable habitat is the first and best approach. Voles avoid open areas, which is why so much of their damage occurs under the cover of deep snow. Decrease the height and density of ground covers and mow very short on the last mowing of the fall. Remove woodpiles and debris and other hiding places. Provide at least a 3-foot bare soil swath around the base of trees — especially young trees — to prevent voles from gnawing on the bark. Remove bird feeders from areas you want to protect.

Use exclusion barriers to keep voles out by placing ¼ inch mesh hardware cloth cylinders large enough to accommodate 5 years growth around the base of young trees. Bury the mesh 3 inches below ground level to prevent voles from burrowing underneath. Make cylinders higher than the typical snow-line level and pinch closed at top to avoid trapping birds. The fencing around garden beds can be reinforced using this method.

Repellents that employ chemical or organic irritants such as capsicum and castor oil can be effective, but not as the only method of control. They require frequent reapplication and product rotation to prevent tolerance from developing. Repellents must be applied in early spring before feeding patterns are established

Traps are not very efficient due to voles’ rapid reproductive rates. However, mouse snap traps, placed by tunnels/runways and baited with peanut butter, oatmeal, apple may help in small gardens or by especially valuable plants. Cover these traps with a shingle to protect non-target creatures. Traps with poison bait stations (that prevent consumption by pets and others) are a sub optimal solution because voles are a prime food source of many predators such as snakes, owls, foxes, and hawks. Read labels carefully if using them. Place stations in areas with evidence of recent vole activity just before the first heavy snow. For large infestations, especially for commercial growers, certified pesticide applications are an option. As with traps, it’s important to use exclusion boxes that protect other wildlife.

Reevaluate:

There is no one and done solution for voles. Review your prevention tactics in every season. If mold or vegetation appears in runways or burrow entrances, it means they’ve moved on. Lawn damage usually repairs itself. If your lawn has winter damage rake out dead grass to encourage the crowns to start growing. Young trees girdled more than 50 percent have a low survival rate. Valuable trees may be bridge-grafted before dormancy breaks. Reduce stress by careful watering and fertilization during the growing season.

References and Resources

National Association of Landscape Professionals. Blog Post 2/22/2022, Landscape Challenges: Dealing with Voles. https://blog.landscapeprofessionals.org/landscape-challenges-dealing-with-voles/ Accessed 12/03/2022

NYS Integrated Pest Management, Cornell/CALS. What’s Bugging You: Wildlife. https://cals.cornell.edu/new-york-state-integrated-pest-management/outreach-education/whats-bugging-you/wildlife Accessed 10/10/2022

University of Connecticut College of Agriculture. Health and Natural Resources Extension News, Blog Post April 3, 2015. Winter Vole Damage to Trees and Plants, https://news.extension.uconn.edu/tag/voles/# Accessed 11/14/2022

University of Massachusetts at Amherst, Center for Agriculture, Food and the Environment. Mole and Vole Damage to Lawns Fact Sheet. https://ag.umass.edu/home-lawn-garden/fact-sheets/mole-vole-damage-to-lawns Accessed 11/30/2022

University of New Hampshire Extension. Managing Voles in New Hampshire Orchards and Highbush Blueberries [fact sheet] https://extension.unh.edu/resource/managing-voles-new-hampshire-orchards-and-highbush-blueberries-fact-sheet-1 Accessed 12/3/2022