Small Mammals of North Dakota
Meadow Vole
Microtus pennsylvanicus
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The meadow vole is common across North America and can be found statewide in North Dakota. This vole species requires water and, therefore, prefers moist to wet meadows. It usually lives in lush, dense vegetation along edges of sloughs, streams, or rivers. They are sometimes found in drier habitats given sufficient cover is available.
Meadow voles have a body about 4 inches long and a tail of about 1 1/2 inches. They weigh roughly 1 l/2 ounces and their ears are short. The back and sides are grayish brown and belly is much lighter. These small mammals can be distinguished from mice by their relatively short tail.
Voles live in "runways" of dense grasses above ground. Burrows may be constructed but are usually not because of waterlogged soils associated near wetlands. Instead, nests are built on the ground in a clump of grass. They are spherical, 5-6 inches in diameter, and constructed of dry stems and leaves with a lining of shredded plant material.
Voles are promiscuous breeders and may produce litters at any time of the year. Females breed with any male attracted to them. Gestation is about 21 days upon which time a litter of 4-7 young is born. After about a month, individuals are sexually mature. Litters produced in the summer where food is more plentiful are larger than those produced in the winter. Most females do not live long enough to produce more than one or two litters.
Meadow voles eat most available species of grasses and herbaceous plants. During periods of high population, they will eat the bark of trees below the line. Their populations will fluctuate in cycles of every 2-5 years. Peak densities between 60 and 250 per acre have been recorded. After getting to a peak, the population will "crash" and only one vole per acre may be left.
It is during peak populations that predators may survive primarily on voles. One study listed 27 birds, 20 mammals, 12 snakes, the bull frog, snapping turtle, northern pike, and bass as eating voles. Although many are consumed during peak populations, predation or severe winters do not seem to cause the fluctuations of meadow vole populations.
| Voles leave behind their mark on trees below the snows surface. During winters with substantial snowfalls, voles will travel through snowbanks in search of food which often happens to be your favorite tree. |
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