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 deer mice, (Peromyscus
sp.); meadow voles, (Microtus pennsylvanicus) and pine voles
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).
General Physical Characteristics
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 deer mice 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 under-parts, 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.
general, mice can cause much damage because of their physical capabilities.
They are excellent climbers and swimmers. House and white-footed deer
mice 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 is 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 and Deer Mice
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
Here are some helpful pointers:
- Use good cultural methods to enable planted seed to grow as quickly
as possible. Newly-seeded flats and seedbeds can be protected by placing
1/4 inch wire mesh cages or small plastic strawberry-type baskets over
seeded areas. In the field, make sure edges are buried several inches
into the soil. Cages can be made large enough to protect small trees,
blueberries and other shrubs. Cages should be at least 1/2 to one inch
from the trunk. In the field, stake, trellis or cage plants such as
peas or tomato to keep the fruit off the ground.
- Common snap-back mouse traps are effective to eliminate mice in homes
or structures. Bait with oatmeal, peanut butter, cheese, sunflower seed,
moistened rolled oats or cotton balls (for nesting material). Use many
traps, check them daily, re-bait and reset as needed. Traps should be
placed along the sides of runways and perpendicular to the runways.
Gloves should be worn when setting traps to reduce human scent. Placing
unset baited traps in runways for several days to allow mice to become
accustomed to them may increase effectiveness when they are set.
- In out-buildings, such as barns, cats have been a popular method
of mouse control for a long time.
- Although mice have an aversion to some odors and tastes, at present
no repellents have been found to solve a mouse problem completely. The
use of frightening sounds is not effective in field situations.
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:
- Eliminate weeds, ground cover and crop litter in and around cultivated
areas. This reduces the availability of food and cover for voles, and
the capacity of these areas to support them.
- Permanent sod strips between blueberry or raspberry rows must be
mowed regularly. A weed-free or vegetation-free strip is an excellent
buffer around areas to be protected. The wider the buffer strip, the
less likely voles will cross it to the cropping area.
- Frequent tillage removes cover, destroys existing runways or tunnels
and destroys a percentage of the existing population.
- Wire or metal barriers (tree guards) at least 12 inches high, with
a mesh size of 1/4 inch or less around blueberries or trees, will exclude
meadow voles. Bury the bottom edge six to ten inches to prevent pine
voles from digging beneath the barrier.
- Mouse traps, or snap-back traps, can be very effective in reducing
the vole population. Place the trap perpendicular to the runway with
the trigger end in the runway. Apple slices or a peanut butter-oatmeal
mixture makes good baits.
A section of roofing shingle placed over the burrow opening and baited
with an apple slice will attract voles. A trap can also be placed under
this shingle, as voles are readily attracted to shingles or pieces of
plywood placed on the ground. Shingles should be bent to form an A-shaped
root. Plywood or flat material should have small blocks under the corners
to allow for a crawl space. These shelters can also serve as bait sites.
Leave in place a few days before baiting to allow the animals to become
accustomed to it.
In general, fumigants are not effective due to the complexity and shallowness
of vole tunnel systems. Frightening agents have not proven to be satisfactory
For pesticide recommendations call the UConn Home
and Garden Education Center at 877-486-6271.