When food sources dwindle, voles (small mouse-like animals, 4 to 8 inches long) damage woody plants by chewing on the bark layer of a tree which interferes with the tree’s flow of nutrients. This girdling damage can be identified by gnawed strips of irregular, clearly defined tooth marks, about 1/16 to 1/8-inch wide. Occasionally stems may be chewed through and have a somewhat pointed tip. Junipers, other shrubs and trees that appear to suffer from drought or disease should be examined closely at the base for signs of injury.
Meadow (Microtus pennsylvanicus) and Prairie (Microtus ochrogaster) voles are common along the Front Range. Because heavy snowfall protects voles from predators, vole damage to Front Range landscapes appears to be above average during heavy snowfall years. Voles tunnel through lawns and golf courses, leaving unsightly lumps and runways. Where tunneling is plentiful the soil may have a spongy feel. Damaged lawns usually fill in as the weather warms in the spring. If injury is severe, rake, fertilize and water the affected area.
The lawn can be over seeded, if needed, in mid-April. Just scattering grass seed over the damaged turf is ineffective. Sow your grass seed after working the soil to insure that the seeds come in contact with the soil and will germinate.
Manage this tunneling by excluding with a stout, 1/4 inch wire netting in fall. It may become necessary to remove ground covers and grasses near the base of trees and shrubs to help manage voles. They do not like exposed areas.