In Connecticut, there are several kinds of mice and voles that may cause damage to gardens, fruit and other plantings: house mice, (Mus musculus); white-footed mice and deermice, (Peromyscus sp.); meadow voles, (Microtus pennsylvanicus) and pine voles (Microtus pinetorum). (see vole photos)
Mice and voles are more common than moles (burrowing, insectivorous, nearly blind and furry mammals), shrews (related to the moles and distinguished from them and the mice by a long pointed snout and very small eyes) and rats (larger than mice, with total body length from 15 to 17 inches).
There are also differences among mice and voles. House mice are tawny to dark gray on the back, gradually changing down the sides to ashy gray on the abdomen. Their feet are shorter, broader and much darker than those of white-footed mice. Their tails are as long as their bodies but are shorter and less hairy than white-footed mice tails.
White-footed mice, the most common species, and deermice have white feet and abdomens, large ears and eyes, and tails as long as their bodies. The color of the sides and back of these mice varies from dark gray to nearly black. They weigh 50% more than house mice and lack the mousy odor of house mice.
Meadow voles, commonly known as meadow mice, are stocky with small, but prominent, beady black eyes and almost concealed ears. Their short tails are about twice as long as their hind feet. Meadow voles are five to seven inches long at maturity and weigh twice as much as house mice. Their dense, shaggy fur is gray to brown with gray underparts, sometimes mixed with yellow or buff.
Their close relative, pine voles or pine mice, have smaller bodies, shorter tails, sunken eyes and underground burrow homes. Pine voles feed on plant roots and crowns.
In general, mice can cause much damage because of their physical capabilities. They are excellent climbers and swimmers. House and white-footed deermice can run up almost any vertical, roughened surface and climb and balance on wires. Their chewing of electrical wires may start fires. Mice can jump one foot straight up, live in temperatures as low as 14 degrees F and squeeze through an opening slightly larger than 1/4 of an inch. Their sense of smell in acute. In six months, a pair of house mice can eat about four pounds of food while excreting some 18,000 fecal droppings or pellets. Although mice are not blind, they do have poor vision and are unable to see clearly beyond six inches.
In considering control measures for mice, it is important to know where they live and how they feed. Mice live in grassy or bushy areas, nesting underground in shallow burrows or aboveground in densely vegetated or protected areas. Also, they can build nests in thick hay or leaf mulches in the garden or cropping areas. Nocturnal feeders, mice are active throughout the year. They forage along narrow surface runways from their nesting areas to their sources of food. In addition, they travel and feed underground via old mole tunnels.
The bark and roots of young trees are gnawed and severely damage by mice. Ripening tomatoes, cucumbers, beans, peas and other fruit close to the ground are bitten into. Developing roots or tubers of potatoes, carrots, beets and parsnips are dug into and eaten by mice, as well. Mice often invade homes or sheds in the fall. In wintertime, their runways are made below the snow cover where they dig up and eat seeds, nuts and bulbs. They feed on tender bark and foliage of shrubs, roses and small fruits such as blueberry.
White-footed mice are commonly found in diverse habitats including open, grassy, brushy and wooded areas. They spend the winter as a family group in a nest made of stems, leaves, sticks and roots and lined with fur, feathers or shredded cloth. Nests are found underground or in protected areas such as old burrows, under boards, hollow logs or buildings. Breeding occurs from spring to fall, with two to four litters of one to eight young per year. Mice born in spring or summer may breed that same year. White-footed mice feed in an area from 1/3 to 4 acres.
With the characteristics and habits of mice in mind, plan your control program. Here are some helpful pointers:
In Connecticut, meadow voles are more abundant and destructive than pine voles. Although damage to fruit tree root systems by pine voles often results in serious economic loss to fruit growers, for the purposes of this fact sheet, we will focus on meadow voles. Meadow voles eat a wide variety of crops and plants, with a preference for grasses. When vole populations are high, many field crops are eaten. Their extensive tunnel systems cause root destruction and interfere with crop irrigation, as well. In late summer and fall, voles store seeds, tubers, bulbs and rhizomes in their tunnels.
Voles are active day and night the entire year. They construct a complex tunnel system with surface runways and numerous burrow entrances. A single tunnel system may contain several adults and young.
Voles have short life spans, ranging from two to sixteen months. Breeding occurs primarily in spring and summer, producing from one to five litters of three to six young per year. Females mature in 35 to 40 days.
The following suggestions will help in vole control:
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