Of the 12 unique species of voles we have in Alberta[1]https://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex594/$file/683.pdf?OpenElement, the meadow vole is the most common type of vole. Voles are a large nuisance to many homeowners in Alberta, as they will burrow underneath the snow in the winter time and destroy lawns, they will girdle (eat) the base of small trees, saplings and bushes, and they will dig their burrows underneath patios, driveways, and foundations, causing them to sink and crack over time. For these reasons, many homeowners want these creatures controlled in order to avoid large damage costs in the future.
Identification
Voles look like house mice, but have a shorter tail, a rounded muzzle and head, and small ears.[2]https://www.canada.ca/en/health-canada/services/pest-control-tips/moles-voles.html The meadow vole has a dense undercoat and is the darkest coloured mouse, ranging from dark gray to yellow-brown or red, obscured by black-tipped hairs.[3]https://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex594/$file/683.pdf?OpenElement The average length of adult meadow voles is 167.5mm (range 140-195mm), with the tail being one-third to one-half the length of their body. Adult meadow voles weigh 33.75 to 54.25g.[4]https://animaldiversity.org/accounts/Microtus_pennsylvanicus/
Risks
Just like mice, voles pose 2 main risks for property owners: health risks and structural damage risks. Much like mice, voles carry a wide array of diseases which can be spread to humans through droppings, urine, biting, and scratching. Voles will live underneath the snow in the wintertime and feed on the grass, which can leave trails of dead grass in the spring and take months to regrow. Voles will also girdle (chew on the bark around the base of trees and bushes) which cuts off the water supply to the rest of the plant, killing it over time. Lastly, voles like to burrow underground. They tend to burrow underneath sidewalks, patios, driveways, decks, and even the foundation of your house. The chambers in these burrows can get quite large over time and cause substantial structural damage to whatever is above it, which can be quite costly to repair.
Signs of Infestation
- Girdling: Bark that has been removed completely around the base of a tree.
- Trails: 2.5 to 5 cm wide dead strips (surface runways) through matted grass leading to shallow underground burrows.
- Droppings: Small piles of brownish droppings (feces) and short pieces of grass along the runways.[5]https://www.canada.ca/en/health-canada/services/pest-control-tips/moles-voles.html
Elimination
Voles can be tricky to treat yourself due to strong rodenticide regulations in Canada. Homeowners that do not hold a valid pesticide applicator license are limited to schedule 4 pesticides, which are generally ineffective and not labeled for voles. The best solution for do-it-yourself treatments is to set up a trapping program for voles. Although this can be very time consuming and require regular maintenance, it is by far the most effective way to treat voles without using commercial pesticides.
Treatment for voles is generally needed on a regular basis. If you have voles on your property, it is likely because there is a natural habitat nearby where they are coming from, such as a grassland, forest, ravine or other greenspace. A single treatment for voles will provide temporary relief, however it will not solve the problem in the long run. Many companies offer a service like this, however it is not something we advise people to do and is generally an ineffective use of money. Our exterior rodent control program consists of regular seasonal maintenance visits that will keep the issue at bay indefinitely.
Prevention
Voles can be tricky to prevent, and in my experience I have seen many homeowners perfectly follow prevention guidelines and still end up with voles. I find that where you live is a far bigger factor than how you maintain the yard in determining whether or not you get voles. Nonetheless, I have included the recommendations from Health Canada for preventing voles in a yard.
- Cleaning up all possible food sources like vegetables left in the garden at season’s end will help keep voles and other rodents away from your yard.
- Use metal or glass rodent-proof containers to store seeds and bird feed. Composters should also be inaccessible to rodents.
- Gravel or cinder barriers around garden plots are an effective and easy means of protection. The barrier should be 20cm deep and a foot or more wide.
- Commercial plastic tree guards, a piece of chicken wire or small mesh wrapped around the base of trees and extending below the soil will help prevent tree girdling.[6]https://www.canada.ca/en/health-canada/services/pest-control-tips/moles-voles.html
Habitat
Wet meadows and open grassland near streams, lakes, ponds and swamps. Meadow voles will very rarely live in forested areas. Overhead grass cover is essential in order to hide from predators. Meadow voles will make burrows just under the surface of the ground.[7]https://www.gov.nl.ca/ffa/wildlife/snp/programs/education/animal-facts/mammals/meadow-vole/ Voles will remain active day and night, year-round, however you rarely see them as they hide in dense vegetation and avoid sunlight when possible.[8]http://ipm.ucanr.edu/PMG/PESTNOTES/pn7439.html
Diet
Eastern meadow voles eat most available species of grasses, sedges, and forbs, including many agricultural plant species. Leaves, flowers, and fruits or forbs are also typical components of a summer diet. They occasionally consume insects and snails, and occasionally scavenge on animal remains. Cannibalism is frequent in periods of high population density. Meadow voles may damage woody vegetation by girdling when population density is high. In winter, meadow voles consume green basal portions of grass plants, often hidden under snow.[9]https://en.wikipedia.org/wiki/Eastern_meadow_vole
Lifecycle & Reproduction
In the wild, voles have an abundance of predators and environmental risks. This means that the average meadow vole lifespan is less than 1 month. Studies have found a mortality rate of 88 percent for the first 30 days after birth. The maximum in the wild is 16 months, and studies have found that some voles can live more than 2 years. Voles have been reported to exceed population densities of 1,482 voles per acre in ideal conditions.[10]https://www.fs.usda.gov/database/feis/animals/mammal/mipe/all.html
Gestation lasts 20 to 23 days, with voles reaching their maximum size within 12 weeks. A typical meadow vole litter consists of 4 to 6 young, with extremes of 1 and 11. Female voles will reach sexual maturity and become pregnant in as little as 3 weeks. One female vole will have as many as 17 litters per year. If breeding begins in April, it is estimated that 100 pairs of voles could create 8,900 voles by September.[11]https://www.fs.usda.gov/database/feis/animals/mammal/mipe/all.html
References