October 3, 2009
What to Do About Woodchucks
Woodchuck burrows and tunnels may give gardeners heartburn, but simple fences can solve most problems
The woodchuck (a.k.a. groundhog) is often caught between being a celebrity and a villain. One day we rely on their shadow to forecast the seasons; the next we grumble as they make a meal of our carefully planted garden vegetables.
Even when the potential for conflict is high, there are ways to deal with woodchucks that make it possible to live in harmony with them. If woodchucks must be evicted from an area, however, it should be followed by addressing the factors that caused a problem in the first place.
- Evicting woodchucks from a property/residence
- Closing burrows
- Scare devices
- Habitat modification
- Keeping woodchucks from returning to abandoned burrows
Woodchucks occasionally eat garden or field crops and can cause considerable damage in a very short period.
Because woodchucks hibernate, they are unlikely to cause any damage between early November and late February. Damage done during this time is more likely to be caused by deer or rabbits.
The woodchuck's burrow systems are regarded as problems on agricultural land, because farm machines can be harmed when they run over a mound. And many horse owners fear their horses will trip over woodchuck burrows in paddocks and injure themselves.
From time to time there are even claims that people are hurt by tripping in woodchuck burrows. This is possible, but far down the list of threats to our own species
To some, woodchucks may be simply "vermin," animals that are of no known service to humans. Just the possibility that woodchucks might cause problems one day is used as an excuse to "control" them.
Woodchucks may not appear useful to humans, but they have their own place and identity in the ecosystem and should be accepted—and respected—for that alone.
They provide food for coyotes, foxes, weasels, badgers, hawks, and eagles. Their burrows give shelter to amphibians, reptiles, smaller rodents, and even larger animals such as foxes.
People and woodchucks can coexist for years without conflict. If you have a woodchuck burrow on your property and don't have any conflicts with its occupants we say—let it be.
Where woodchuck burrows are deemed to be problems, eviction and exclusion are the recommended courses of action.
Woodchucks can be harried from burrows by harassment assaulting the animal's senses, or by disturbing the burrow system. However, there is only a small window of time in the year when this can be done humanely, so timing is crucial.
Before attempting to evict and exclude woodchucks, consider that breeding female woodchucks have dependent young in their burrows from late winter until spring or early summer, and evicting them during this time can be inhumane.
Females will resist abandoning young, even under great duress. But wait too late in the year when woodchucks put on weight and secure a suitable location to hibernate, you will impeade their winter survival. The best time to evict woodchucks from burrows is from mid- to late summer or between early July and late September in most areas.
If you watch closely, you may actually see the young woodchucks as they first venture aboveground. If you do, you can begin your eviction about three weeks later with relative assurance that it will avoid affecting dependent offspring.
Before closing a burrow, first test for activity: Loosely plug all of the burrow entrances (there may be several) with grass clippings, newspaper, or similar material and monitor activity to determine if the burrow is currently vacant.
If, after three to five days in clear summer weather, the material has not been disturbed, you can assume the burrow is unoccupied.
Use heavy-gauge, welded fencing wire (with no larger than three-inch squares) to close burrows.
- Cut the wire into three-by-three foot sections.
- Center a section over each burrow entrance.
- Bury the fencing at least one foot deep.
- Pin it down if necessary with landscape staples.
If the burrow system is occupied, harass the residents:
- Partially dig the entrance out.
- Clear vegetation away from entrances.
- Put some harmless but strong-smelling substance just inside the entrance (such as urine-saturated clumps of kitty litter).
- Loosely seal the entrance, so the smell stays inside the burrow.
Monitor the closed burrow every few days to make sure it's not still occupied; when it is clear that the burrow is empty, you can permanently seal it.
Keep monitoring not only closed burrows but the rest of the yard, too. Immediately responding to any attempts to reopen old burrows or establish new ones is vital to preventing new burrows from popping up.
Even though woodchucks are good climbers, you can protect your gardens with fencing. Fences work best when protecting relatively small areas. To be a successful barrier, a perimeter garden fence should at minimum:
- Be made of a chicken or welded wire with mesh size no bigger than three by three inches.
- Reach three to four feet above ground level.
- Have twelve to eighteen inches of unsecured fencing at the top so it wobbles as the woodchuck tries to climb it.
- Have an L-footer base that is buried or pinned to the ground or a single strand of electric fencing four inches off the ground and six inches in front (to prevent digging).
If you are building a more rigid fence, bend the top ten to fifteen inches outward at a 45-degree angle to create a barrier to help prevent climbing.
Electric fences will work as well, and often a simple single strand of electrified wire set four inches above the ground is enough to discourage visits. If not, you can add one more strand about nine inches from the ground. (Follow standard safety protocols when using electric fences.)
Woodchucks are cautious animals and can be frightened by new objects in the environment:
- Tie a silver Mylar® helium balloons (look for them at the local party store) in the garden on a short line, so the wind occasionally bounces them onto the ground.
- You can also suspend a beach ball in a place where it will catch the wind.
These scare devices may keep them away temporarily, but are more likely to work if they are changed frequently.
Woodchucks like to navigate through fairly high vegetation.
Removing vegetation around burrows can create insecurity and, with other eviction methods applied simultaneously, can encourage them to abandon a burrow system—especially one that hasn't been used for long.
Beyond that, keeping undergrowth and grass cover low may deny woodchucks the security they seek before burrowing around buildings and residences.
During the course of the year, woodchucks routinely move between burrow systems. Frequently a burrow is abandoned or unoccupied for weeks, or even months, before it is reopened.
Even when a burrow's entrance is barely recognizable, the woodchuck's highly developed sense of smell allows them to locate places where others have lived months or even years before.
With only a few minutes' work, woodchucks can reopen a tunnel system and use it again. You can prevent this by burying a three-foot-square panel of welded wire, centered over the entrance hole before an abandoned burrow is rediscovered.
There are no commercial repellents registered for use on woodchucks.
Woodchucks are not considered to be a significant source of any infectious disease that can be transmitted to humans. However, they can get rabies and may be aggressive when this disease has taken its final hold on them. For this reason unprovoked attacks by woodchucks must be treated very seriously as potential rabies exposures.
» Woodchucks have been the object of dozens of university extension bulletins, most of which encourage lethal control. As is the case with voles and other species, good books about living in harmony with woodchucks remain to be written.
» If you are located within the D.C. Metro Area, take advantage of our wildlife conflict resolution service. Learn More
» Purchase a copy of Wild Neighbors; the go-to guide for useful, humane solutions to conflicts with wildlife.