Cage and box traps are effective in capturing woodchucks (also known as groundhogs or "whistlepigs"). The best time to trap woodchucks is early spring when food sources are limited. Place cage traps covered with dark canvas and baited with apples or carrots near the burrow entrance. Wire the trap door open for several days to allow the animals to take the bait regularly. Once this has happened, set the trap.
Be sure to check the trap at least twice per day (in the morning before the day gets hot, and in the early evening so an animal trapped in the day doesn't stay in the trap all night as well) so that the captured animal can be dealt with (removed or euthanized) in a humane manner and in accordance with state laws. Remember, for the animal, being in the trap is a stressful experience. Set the trap in the shade, or cover it with burlap or cardboard so the sun doesn't shine directly on the animal.
Additional trapping and control suggestions can be found in the links below.
Online Resources:
Woodchuck Control
