Voles are compact, heavy-set rodents with small eyes, inconspicuous ears and greyish-brown fur that cause trouble for homeowners in Calgary primarily in winter. Working under a concealing mantle of snow, these rodents can kill or severely injure trees and shrubs by girdling roots and stems. They prefer young, thin barked plants, but may also feed on ground bulbs or the exposed roots of older trees.
Preventing and controlling voles
Mowing your lawn will reduce the chances of a vole invasion since tall grass provides ideal habitat for voles. Homeowners should also maintain grass-free areas around trees, shrubs and gardens.
Specialized vole-guards made of hardware cloth are often used to protect trees and plants from damage. The cylindrical, wire mesh guards should be submerged two to three inches into the soil and should extend two inches above the height of the anticipated snow line. A mesh size of a quarter of an inch or less is suggested.
Repellents can be applied in early fall to tree bark, which voles will eat when food is scarce. Repellents can complement other measures, but have limited effectiveness when used alone.
Trapping is a practical means of controlling vole populations on small acreages and in backyards in and around Calgary. Choker-harpoon and scissors-type traps work, but large snap-type mousetraps are more available. Bait traps with equal parts molasses, peanut butter and oats. If you are concerned that non-target animals may be captured, employ the use of tunnel traps or above ground trap covers.
Signs of voles
In some years, populations of voles can explode, exceeding the ability of natural predators to keep numbers at tolerable levels. Be on the lookout in early fall for signs of a large vole population build up in your community. The signs include:
- Runways in accumulations of grass clippings and other plant materials
- Chewed fruit
- Fresh grass clippings