If there’s one animal that seems harmless, it’s the field mouse, or rather, the eastern meadow vole (Microtus pennsylvanicus), a small rodent barely larger than a mouse. It is easily distinguished from the latter, which is mainly an indoor animal, by its smaller ears and short tail, as well as by its brown coloration (the house mouse is gray). The vole is ubiquitous on our land, but generally goes unnoticed, as it is mainly nocturnal from spring to autumn.
The damage it causes is hardly noticeable in summer, when there’s an abundance of things to eat (seeds, insects, foliage, etc.), but in winter, when the ground is frozen and its traditional food sources are no longer available, it finds other food: the bark of shrubs and young trees and, occasionally, tulip bulbs and the roots of our perennials.
Under the Snow
During the summer, the vole wanders under the ground or through the foliage of flowerbeds, lawns and so on. They are very shy then, as many predators are on the prowl, especially cats in urban areas. In winter, however, they become more daring. It digs tunnels through the snow. Thus protected from predators, it becomes diurnal.
Indeed, cats are no longer of any use in controlling them. Outside the city, however, foxes, coyotes, wolves, lynxes and other predators have tricks for finding them, despite the protection of the snow. They listen carefully and, thanks to their exceptional hearing, manage to locate them, then jump in with clawed paws to poke holes in the snow to attack them. In the city, in the absence of any viable predator, voles, which are very numerous at the end of summer, give themselves over to their favorite winter pastime: the search for interesting bark to chew.
Voles are not beavers, and can hardly chew the bark of large trees. But shrubs and young trees are a different story. What’s more, they love the bark of apple, cherry and other fruit trees, which is sweet and remains thin even when the trees are mature.
There are a number of tricks you can use to reduce winter vole predation. The most important is not to clean out your flower beds and vegetable garden (instead, do it in the spring, if at all, when voles find an abundance of food). By eliminating their primary food source, you drive them straight to the only remaining food sources: trees and shrubs, bulbs, the roots of your plants, and so on.
You can, however, clear the area around the trees by trimming back dense vegetation where voles could hide. If you’ve planted fruit trees in a lawn, for example, a short mowing during the last autumn mowing will help discourage them.
The problem is that these spirals were developed for a climate where snow is scarce. In our region, snow quickly rises above the level of the protection, allowing voles to chew through the bark beyond the protection. You can, however, place a second spiral above the first to gain height.
An equally effective and less costly trick is to surround the trunk with wire mesh up to the height of the first branches. However, the wire mesh must form a tube so that it doesn’t touch the bark directly, otherwise the voles will be able to chew through the holes in the wire. The wire mesh should therefore be 2 cm from the bark, all the way around the trunk. You can also protect the bark with a section of drainpipe slit lengthwise so that you can place it around the trunk. All this protection needs to be installed late (in November) and removed early (when the snow melts), otherwise it can serve as a winter shelter for insect pests.
There are also repellents that can be sprayed or smeared on the trunk in late autumn. These products are either malodorous or have a pungent or bitter taste. However, they are less effective in a climate as rainy as ours, as they are often washed off before winter arrives, hence the importance of applying them as late as possible.
Larry Hodgson published thousands of articles and 65 books over the course of his career, in both French and English. His son, Mathieu, has made it his mission to make his father’s writings accessible to the public. This text was originally published in Le Soleil on November 6, 2005.