Voles

Overview

Voles, Microtus spp., also commonly called meadow mice, are seldom seen though the damage they do to garden plants may be a too common sight. These are chunky, ground-dwelling rodents about 7 inches long with a tail that is less than 2 inches long. Young voles are gray. Adults are brown mixed with black and have underparts of gray tinged with yellow. Furry black ears do not rise much above the fur and the eyes are black and beady. There are several species of voles, including the woodland vole, meadow vole, and prairie vole. In Missouri, chances are you will be dealing with the prairie vole.

Voles flourish in grassy and weedy areas (including our gardens), creating systems of pathways 1 to 2 inches wide that often are protected by overhanging vegetation. Droppings and fresh bits of plants show that a run is being used. Voles or meadow mice also build underground tunnels and may use mole or mouse tunnels as well. Voles build 6- to 8-inch round nests of grass underground or in logs and similar protected settings.

Mating season lasts from spring to fall with litters of two to nine produced monthly. Females begin reproducing at the age of three weeks. Voles rarely live more than 16 months in the wild though they can reach the ripe old age of nearly three years in captivity.

Voles prefer the bark of young fruit trees as well as tender stems, foliage, flowers, seeds, and fruits of grasses, sedges, and many other herbaceous plants. When times are tough and their favorite foods are scarce, voles will eat crayfish, snails, insects, and even other mice as well as the inner barks of vines, shrubs, and trees. A vole will consume its own weight in plants every 24 hours. They say that a population of 15 voles per acre can grow to 250 in four years. Voles will store food, as much as two gallons of plant materials in underground hollows near their nests as well as hollow stumps and similar places.

Moles often are accused of the plant damage caused by voles. Moles live almost entirely underground and are carnivores, not herbivores. A mole’s diet consists of small animal life, especially grubs and earthworms—no plants. They only chew roots to clear the way for their tunnels.

Symptoms and Diagnosis

Voles and rabbits can cause similar damage. Voles nibble plants and the tooth marks are small, only about 1/8 inch wide, 3/8 inch long, and 1/8 or more inches deep. Rabbit gnawing marks are larger and less clear. Rabbits bite off small branches with clean oblique tooth marks while voles nibble. If you think you have vole damage, look for nearby path systems, which can be extensive and have a number of burrow openings.

Integrated Pest Management Strategies

1. Trap the voles. Mouse snap traps baited with peanut butter will catch voles if placed on the ground perpendicular to a well-used pathway. Place the trap firmly and set the trigger in the pathway. A sprinkle of rolled oats in the pathway will add to the bait’s appeal. Cover the traps with cardboard bent into a tunnel (big enough not to hamper the trap spring)—this will keep birds from getting caught. Use plenty of traps—a dozen for a small garden and 50 or more for a large garden. Wear gloves when handling dead voles.

2. Manage habitat to discourage voles. Keep all vegetation away from the base of trees. Keep grass no longer than 3 to 4 inches. You may have to remove mulch from gardens and around trees if the vole problem is extensive. Keep the ground bare—voles do not like to feed out in the open. Till the soil to destroy runways and paths. Wire 3/8-inch hardware cloth fashioned into cylinders 18 inches high will protect trees when set 6 inches into the soil.

3. Repel the voles. There are repellents made of such things as capsaicin (hot pepper) and predator odors (fox and coyote urine) that may convince voles to go elsewhere when sprayed on garden favorites. Be sure to repeat the spray if it rains. Read the directions carefully before using. A sure-fire vole weapon is a garden cat—cats are very successful at catching voles.