Humane homeowners should remove groundhogs in mid- to late summer to avoid disrupting reproduction and hibernation cycles. After waiting until the appropriate time of year, they can harass and exclude groundhogs from their burrows. Using scent disrupts groundhog living environments without endangering the animals.
First, a homeowner should test for activity by loosely plugging all burrow entrances with grass clippings, newspaper or other light materials. If the material is undisturbed after three to five days of mild summer weather, it's safe to assume the burrow is unoccupied and close burrows with 3-inch squares of heavy-gauge, welded fencing wire.
If the burrow system is occupied, the best method is to harass groundhogs until they relocate. Pest control begins with partially digging the entrance to the burrow out and clearing vegetation away from entrances. After placing a harmless but strong-smelling substance just inside the entrance, the homeowner can loosely seal the entrance so the smell stays inside the burrow, but the groundhogs are not trapped.
After monitoring the burrow for a few days to make sure it is unoccupied, the homeowner can permanently seal the burrow. She should respond immediately to any attempts to reopen closed burrows or dig new ones.
Breeding female woodchucks care for dependent young in burrows from late winter until spring or early summer, and it is inhumane to remove them during this time. However, removing groundhogs too late in the year can impede winter survival. In most areas, late July to early September is the best time to remove groundhogs.