As you may know, the crops in the Canmore community garden have been experiencing some damage this season due to voles. This is not unique to the community garden as these ‘pests’ are all over Canmore this summer in many yards and gardens. A bit of reading portrays them as anything from key elements in a balanced eco system to destructive pests that can do extensive damage to trees, shrubs, lawns and gardens.
Voles are small rodents similar to mice. There are many species of voles but it is most likely we have Southern Red-Backed voles in the community garden.
According to an article from Colorado State University “voles are active day and night throughout the year and do not hibernate. They usually live between two and six months. Their home ranges usually are less than one-fourth acre and vary with season, food supply and population density. Voles construct many surface runways and underground tunnels with numerous burrow entrances. A single burrow may contain several adults and young.
Population densities of voles vary from species to species. Large population fluctuations that range from 14 to 500 voles per acre are common. Their numbers generally peak every three to five years. Population is influenced by dispersal, food quality, climate, predation, physiological stress, and genetics.
Voles have three to six young per litter and three to 12 litters per year. Their gestation period ranges from 20 to 23 days and they breed almost year around, although most reproduction occurs in spring, summer and fall. Females may become pregnant at three weeks of age.
Voles can cause extensive damage to forests, orchards and ornamental plants by girdling trees and shrubs. The greatest damage seems to coincide with years of heavy snowfall.
Damage to crops, such as alfalfa, clover, potatoes, carrots, beets and turnips is common and most evident when voles are at high population levels. Voles often damage lawns and golf courses by constructing runways and burrow systems.”
Voles do have natural predators, for example hawks, coyotes and in urban areas, cats. Other methods to prevent and control damage are numerous: habitat management, exclusion, repellents, trapping, and poison grain baits. In general repellents are not considered very effective in the case of voles. Exclusion would involve installing specialized fencing which would be challenging and expensive in a space as large as the community garden. Poison bates have been ruled out by CCGS as not appropriate in the case of a community garden. Traps are currently being experimented with but going forward habitat management will be best defense, so elimination of weed ground cover and tall grasses by frequent and close mowing and keeping the garden tidy will eliminate some of the available habitat and will reduce their numbers. It is also recommended not to use mulch or straw which also provides the cover voles seek out.