Published on Wednesday, 30 November -0001 00:00
Vole damage was heavy again last winter. As the snow melted this spring, many homeowners found large areas of tunnels and bunches of grass thatch in their lawns and, even worse, the bark chewed off the trunks of small trees and shrubs below the snow line. Although the damage to the lawns can be repaired, the trees and shrubs that are girdled by this gnawing rodent will not survive.
This has been a year of unusual environmental conditions and it is very possible that we could get season-lasting snow on warm soil which will provide the voles with perfect habitat. Voles are small mouse-like rodents that are active through the winter on the surface of the ground underneath the snow and are encouraged by conditions in which there is snow on unfrozen ground. Once they have inhabited and found food sources in a yard, they are likely to remain all winter.
Because they are food for many predators, voles spend the summer in meadows and other grassy areas where the taller grasses will provide protective cover. In the fall they move to home lawns and may enter homes and other buildings in search of food. Because they are often found in grassy areas, they are often called "meadow mice".
The most common vole-related damage is to grass and ground covers in lawns. They remain active under the snow throughout the winter, and as they feed, they create runway systems and nests at ground level, often killing the grass. Voles may also feed on flower bulbs before the ground freezes and they can also cause extensive damage to trees and shrubs by chewing the bark off in a ring around the trunk near the soil line, thereby girdling the plant. There have been situations where they have completely removed the bark on young trees up to the snowline.
To discourage voles from returning to your lawn to overwinter, keep the lawn mowed regularly until freezing and remove excessive thatch. You might consider lowering your lawnmower slightly, but do not mow the grass shorter than two inches to prevent winter damage to the crowns. Eliminate any weeds, wild grass or litter from around the lawn that may provide food and cover for voles. If active runways are present in the lawn, trapping may be effective. Mouse traps baited with a mixture of peanut butter and rolled oats should be placed at right angles to the runways or in areas where voles are active.
There are some poison baits labeled for outdoor use against voles and readily available mouse and rat baits can also be effective. These baits offer the most success in late fall or early winter. Create a bait station by using a soup can, beverage can, section of PVC pipe or a jar on its side and place about a tablespoon of dry pelleted bait in the station. Place the stations at the base of young trees and shrubs that may be the target of vole damage, near any runways that may be in the lawn, and in areas of the lawn that were damaged by voles in previous winters.
Check the bait stations several times each week during the fall and replace any spoiled or consumed bait. Keep these stations in place throughout the winter, as the voles will feed under the snow. Be sure to read and follow all directions and precautions on the label of the poison you purchase to use in the bait stations. It is important to remove these bait stations as soon as the snow has melted in the spring to avoid accidental contact with children and pets.
Young trees and shrubs can be protected with cylinders of hardware cloth or tree wrap. The hardware cloth mesh should be one-fourth inch or less and, because voles can dig, should be buried an inch or two into the soil. Wrapping the trunks of trees with a commercial tree wrap will also prevent vole damage. It is important that the end of the wrap be placed into the soil and the tree should be wrapped well above the potential snow line. Actually, the trees should be wrapped until just below the first branch, which will also protect the tree from rabbit damage and sunscald. It is important that the grass around fruit trees be cut short to eliminate hiding areas for voles and discourage their activity.
By reducing ground cover with mowing, excluding the voles with one-fourth inch wire cylinders around trees and shrubs, and the use of poisonous baits or trapping now, the disappointment that occurs when discovering vole damage in the spring can be minimized.