Lawn tunnels likely from voles burrowing, foraging
Q: With the snow in my garden now mostly melted, I am seeing what appear to be tunnels in my lawn in a few areas. What is happening here, and is there something that I should do now?
— Jermaine Sanders, Evanston
A: The damage you are describing in the lawn was probably caused by meadow voles, which will create well-defined 1 ½to 2-inch-wide surface runways through the turf as they forage for food.
Voles are compact rodents with stocky bodies, short legs and short tails, and can be mistaken for mice. Vole runways in the turf are formed by a combination of the voles eating the grass blades and their constant traveling over the route.
These runways are easy to see when snow melts away in late winter and early spring. There also may be excavated dirt from the burrow system in the runway, resulting in a “dirt” path in some areas. They nest in shallow burrows underground or at ground level under brush or other protective covering. Burrow entrances measure from 1 to 1 ½ inches in diameter. Voles do not hibernate and are active throughout the year, mostly at dawn and dusk.
Voles are most prolific when they have abundant amounts of vegetation and cover. The damage is likely to be more severe during extended cold spells with deep snow cover, which occurred this winter.
They primarily eat the stems and leaves of various grasses, but they also consume other vegetation. They will eat the bark of trees and shrubs during the winter, which is typically the most serious damage of concern. Most voles do not live for more than a few months but can live up to two years, if not eaten by a predator.
Gardens with low-lying landscaping, such as arborvitae, spreading yews, junipers, cranberry cotoneaster and raised beds have higher potential for vole activity. The damage to the shrubs may not be noticed until later in spring, when the evergreens turn brown or the deciduous shrubs do not leaf out.
Check the bases of trees and shrubs in the vicinity of the vole damage you are seeing in the lawn.
Trees that have had the bark completely removed around the trunk from the feeding will likely die. Shrubs with similar damage can be cut back now, in hope that they will resprout from the base below the damaged stems.
You may also want to cut back any herbaceous plant material for a couple of feet away from the bases of your trees and shrubs. Lawns are easy to repair in spring with some overseeding in early April.
Eliminate weeds and dense ground cover around lawns late next fall
to make these areas less able to support voles. Mow lawns and other turf regularly, and cut back vegetation from the bases of trees and shrubs as winter approaches in areas where you have found vole activity this spring.
It is also a good idea to pull mulch back away from the base of trees and shrubs, and keep the snow cleared away from the base of young trees.
Reducing cover makes voles more vulnerable to predators such as hawks and owls. In general, removal of cover is very effective in preventing damage done by voles.
Voles can be controlled by using snap traps that are baited with a combination of peanut butter and oatmeal or with apple slices.
Poison baits designed for house mice are also effective but can cause secondary poisoning in predators if the treated voles are then eaten.