Woodchucks

Overview

Woodchuck

Figure 1:
Photo Credit - Marj Rines

Woodchucks, also called groundhogs, are closely related to the marmots that are common in the west. These grayish brown creatures are typically 16 to 20 inches long including a six-inch tail, and weigh between six and 12 pounds.

Basking in the mid-day sun, families of woodchucks may evoke thoughts of a harmonious existence between humans and nature in suburbia. But many Maine gardeners soon learn that unless they take precautionary measures, most of their precious plantings may be sacrificed to the woodchuck's voracious appetite.

Facts about Maine's Woodchucks

Habitat

In New England, woodchucks inhabit both urban and suburban yards, fields, meadows, woodland clearings, and are frequently seen in grassy areas along highways.

Woodchucks live in extensive burrows two to six feet deep and up to 40 feet long that contain numerous chambers with specific functions such as nesting waste disposal. You can identify the main entrance by an adjacent large mound of dirt that the animal uses for observation and sitting in the sun; in addition, there may be as many as five other openings to the den.

Behavior

  • Woodchucks are active during the day. In summer they commonly feed in the early morning and the late afternoon, spending the rest of the day sleeping or basking in the sun.
  • Woodchucks are among the few true hibernators found in Maine. In late summer they begin to put on weight in preparation for the move to their winter dens, often located in wooded areas. Woodchucks begin their hibernation in October and emerge in February or March.
  • The average life span for a woodchuck in the wild is five to six years.

Food

  • Mainly vegetarians, woodchucks feed on a variety of grasses and chickweeds, clover, plantains and many varieties of wild flowers. They eat blackberries, raspberries, cherries, and other fruits and along with the bark of hickory and maple trees.
  • To the dismay of gardeners, woodchucks love fresh vegetables, especially broccoli, peas, beans, carrot tops, lettuce and squash. They also commonly target asters, daisies, lilies, marigolds, pansies, phlox, snapdragons and sunflowers.
  • Woodchucks will also eat grasshoppers, June bugs and other large insects.

Breeding

  • Woodchucks do not mate until their second year.
  • Males and females breed in March or April, after which there is no further contact; the female raises the young alone.
  • Woodchucks give birth from early April to mid-May following a 32-day gestation period. One litter contains four to six kits. The young open their eyes at four weeks and are weaned at six weeks when they are ready to leave the burrow with their mother. In the fall the young woodchucks venture off to seek their own territories.

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Preventing Conflicts

Protecting Plants

The only true way to protect plants is to install fencing. Ideally, you should do so before the woodchuck gets a taste of your produce. Knowing that food is there strengthens the animal's determination to get through the barrier. Woodchucks can burrow under and climb over fencing so it is critical to plan for these talents.

Technique A: Install five-foot high posts around the perimeter of the garden, then attach six-foot high chicken wire that is buried at least ten inches underground. Leave the top 12 inches unattached and bend it outward so that the woodchuck cannot get a good grip to climb over it.

Technique B: Lay a piece of three-foot wide chicken wire flat on the ground all around the garden. Six inches from the edge closest to the garden, place a four- to six-foot high vertical fence securely on top. As shown below, there will be two and a half feet of chicken wire on the outside of the vertical fence and six inches inside. The top 12 inches of the vertical fence should be left unsecured and bent outward, away from garden. The horizontal section of chicken wire will prevent the woodchuck from digging under the vertical fence.

Figure 2

Technique B for excluding woodchucks from a garden. (Fig. 2)

Other options: When proper fencing is not possible, you can try other methods, but they are by no means guaranteed:

  • Plant species that reputedly repel woodchucks, such as gopher plant (Euphorbia lathyrus) or crown imperial fritillary (F. imperialis) around the perimeter of the garden.
  • Allow a pet dog access to the planted area.
  • Repeatedly treat the area with repellents such as fox or coyote urine, diluted Tabasco sauce or red pepper flakes, or scattered human hair.
  • Construct a visibility barrier such as a three-foot black plastic wall before the woodchuck identifies the area as a foraging ground.

Encouraging Woodchucks to Relocate

From burrows: Do not interfere with woodchuck burrows until after the young are capable of leaving, around the first of July. Flag holes in walkways that present a hazard to people, pets or farm animals.

After the young are able to leave, you can an attempt to drive the woodchucks from their burrow. Locate all the holes and stuff all but one with rags which have been soaked in a petroleum product. The rag gives off an odor repugnant to the woodchucks and they may relocate. Mothballs can also be used as an offending odor. There is no guarantee that the animals will leave the property; they may just move to another location in the same yard.

Near buildings: Woodchucks often conceal their entrance hole by placing it under a rock, in a thicket, or under a building. Rarely is the structure of the building affected. Close these openings with wood, concrete or half-inch hardware cloth. To prevent the woodchucks from burrowing, dig a one-by-one foot trench around the base of the structure. Nail the fencing to the bottom of the building and bury it underground as shown below.

Another option is to install three-foot wide chicken wire around the perimeter of the building, sliding it under the structure about six inches. (see below) If the base of the building is more than four inches above the ground, also place vertical fencing around the perimeter.

Proventing

Figure 3

Proventing

Figure 4

One technique for preventing woodchucks from burrowing. (Fig. 3)

A second technique for preventing woodchucks from burrowing. (Fig. 4)

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Public Health Concerns

All mammals, including woodchucks, are susceptible to rabies. Rabies is a viral disease that attacks the central nervous system and is invariably fatal if untreated. The virus, found in the saliva of an infected animal and transmitted through a bite or scratch, manifests itself in two forms: "furious" rabies and "dumb" rabies. The symptoms, which appear anytime from two weeks to three months after exposure and vary in each species, cause marked changes in behavior. An animal with the "furious" form can become aggressive, disoriented, and snap or bite at anything in its path. An animal with the "dumb" form is unnaturally tame or friendly.

If you suspect that you have been exposed to rabies, immediately wash the area with soap and water and seek medical attention. The treatment of rabies no longer requires a series of shots in the stomach.

Use good judgment and common sense. Have your dogs and cats vaccinated against rabies, avoid contact with wild animals and unfamiliar domestic animals, and be sensitive to unusual behavior patterns in pets. Obey state laws that make it illegal to possess or transport and relocate wildlife.

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If a woodchuck is causing damage or is a nuisance, consult Maine's laws on this subject.

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Additional Information

Internet Resources

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