Montane vole

Mountain vole / Microtus montanus

Montane Vole	Distribution of the Montane Vole
Pictures from - National Museum of Natural History ©2004 Smithsonian Institution

Physical characteristics The montane vole is 5 ½ to 8 ½ inches in length. Its fur is brown, washed with gray or yellow, and mixed with some black-tipped hairs. Its feet are usually silver-gray and the fur under its body is whitish. The tail is bicolor.

Reproduction Montane voles make a nest of dried grasses that is constructed in a burrow excavated in moist soil. When the vegetation is green and succulent, reproduction is stimulated, whereas when the vegetation is dry and mature, reproduction is inhibited. Mating can occur year round, but is probably restricted to March - November at the higher elevations. Mated pairs of montane voles do not share a nest. The male montane vole is promiscuous. The gestation is 21 days and litter sizes are usually 5-6. The young wean at about 3 weeks, and the females are sexually mature soon after weaning. When the populations are low in an area, females abandon the nest and young after weaning. When populations are high, extended maternal families are formed in which a female may stay in the nest for 2 successive litters. So when you see a cluster of burrow openings, it is necessary to do the Apple Sign Test to confirm that this is an active area before you place a bait station there.

Ecology Montane voles spend most of their lives above the ground, but can also make shallow tunnels in the ground. They are active year round and are active mostly at night but may also be active during the day. They prefer runways in open grass but stay and hide where there is a protective cover from predators such as hawks. Montane voles prefer meadows or grasslands that have a water source. Their home ranges average about a quarter of an acre, or 10,000 sq. ft. The Tent setup with the Vole Control Bait Station is most effective in controlling voles in the open grassy areas, because they feel safe from predators while they eat the bait. Occasionally, Montane voles may have tunnels under the mulch in your landscaped areas, if so, use the Mulch Covered Method setup of the bait stations to gain control in these areas.

Signs of Meadow Vole Activity rook for clipped runways in the grass, piles of clipped grass stems with out the seed heads.

Picture provided by B. Guddat from Nevada A cluster of many burrow entrance holes is a common sight in lawn and pasture areas where montane voles are present. The home range of this vole is about a 100-foot radius around the entrance holes.

Picture provided by B. Guddat from Nevada Notice the entrance hole at the lower right, and the clipped grass along its runway.

Montane voles gnaw and girdle trees and saplings at the ground level. Vole gnawing can be differentiated from the gnawing of other animals by the non-uniform gnaw marks. They occur at various angles and in irregular patches. The girdling may be higher in the winter months if snow cover exists.

Picture provided by B. Guddat

Rabbits also chew on young trees, but their gnawing begins several inches above the soil line. Rabbits have much larger teeth than voles and their regular gnaw marks on the trees will show this.

When snow cover is present, voles are protected from predators and their activity can go undetected until it is too late. They can damage the trunks and roots of trees by gnawing. The gnaw marks are about 1/16 to 1/8 inch wide and 3/8 inch long found in irregular patches and at various angles. If this gnawing completely surrounds the root or trunk of the tree or shrub, it will kill the plant. This is called girdling.

It is important to act before vole numbers get too high, especially before winter snow provides cover. The damage they can do to ornamental plants, trees, and garden plants can be quite severe and take several years to replace.

With their high reproductive potential, any remaining voles could repopulate an area quickly. With this potential for severe damage to your landscape and garden, a homeowner cannot afford to do nothing and assume a predator will control the problem. You must take immediate action to prevent the loss of valuable plantings. Effective action involves using the Vole Control Bait Station System, habitat modification, and regular monitoring in the fall and spring with the Apple Sign Test to detect any resurgence from surrounding areas. Pay particular attention to surrounding areas of your property that have heavy vegetation because such areas are likely sources of invasions.