It’s easy to admire big animals, but without tiny critters, nothing can survive. From the soil, which insects feed on, microscopic organisms which themselves become food for predators, up through the food chain; everything relies on something smaller to survive.
One of the most overlooked mammals is the Meadow Vole, a small mouse-like animal; living in fields, damp wetlands and forest edges is a primary food source for most of the avian, many of the mammalian predators and even several reptiles and amphibians. Let’s explore its life a bit.
But first, how do you know if it’s a mouse or a vole? Voles have small eyes and ears, a stocky body, a tail shorter than their body, while mice have large ears and eyes, a lean body, a tail longer than the body and often have a more varied coloured pelage (i.e. fur). Mice of all kinds are more tolerant of people and often come into homes and cottages, where voles generally stay out in the fields.
Found virtually across all of Canada and much of the northern USA, the Meadow Vole is an integral part of many landscapes. Uniformly dark brown in colour, its features are hard to discern, but if you see a dark brown, short-tailed “mouse” running through the grass at high speed, and it is about 5-7″ long, then it is likely a Meadow Vole.
It is a prolific breeder, subject to incredible variations in local population numbers, and can breed when only 20-25 days of age. According to Penn State experts, “Gestation (of litters, ranging from 2 to 11 pups) takes less than a month. Females may mate almost immediately after giving birth, and, so, after weaning one litter (which takes 21 days), she may then have another. It is possible for a female meadow vole, in southern Canada, to have … 8 litters” in a single year. But factor in the fact, almost every predator seeks out this tiny morsel and, at 57-110 grams in weight, it takes a lot of them to keep hungry predators satisfied. You can never have too many!
The young are born naked and blind, and after three days, the fur starts to appear. They open their eyes and start to crawl when they are about a week old.
When they are about 14 days old, they are weaned off milk and start consuming solid food. The main summer components of their diet are grasses and sedges. They switch to grains, seeds, bark, roots, and dried fruits in winter. They do not hibernate, so they must feed every day. Being voracious eaters, they eat daily on average 60 percent of their body weight! The female’s home range is tiny and averages about 400 sq. ft. (40′ x 100′), so an average urban yard can represent the entire home range of a single vole. On the other hand, Males are not as range-restricted and will wander freely between territories, ensuring genetic variability in the population as a whole.
Meadow voles poop a lot, and this is an important source of nutrients for grasses and other plants where the voles forage. Very importantly, voles accelerate the dispersal of vital mycorrhizal fungi in the soil (e.g. A fungus which grows in association with the roots of a plant in a symbiotic relationship) and, thus, influence the survival and growth rates of many important species of trees. I have written of this unseen but vital aspect of a healthy forest ecosystem in previous columns.
Meadow voles are most abundant in shrub and field ecosystems, when these unique ecosystems are in their early successional stages of development. The presence and activities of voles greatly influence the rate and scope of subsequent successional stages, based on their input of nutrients, dispersal of seeds and “pruning” activities as they nibble on winter shoots.
So next time you let your cat out, and it kills a ‘mouse,’ maybe think for a moment about what hawk, owl or fox was deprived of a meal as a result, but that’s another topic.
Geoff Carpentier is a published author, expedition guide and environmental consultant. Visit Geoff online on LinkedIn, Facebook and Instagram.