Woodchucks in Massachusetts
Woodchucks are common and abundant in Massachusetts. They are found throughout the state except on Nantucket and Martha’s Vineyard. Often called “groundhogs” or “whistle-pigs,” they are not in the pig family at all. Woodchucks are burrowing members of the squirrel family, which includes tree squirrels, flying squirrels, and chipmunks. In the western U.S., there are five related species called “marmots.”
Woodchucks are medium-sized, chunky, ground-dwelling squirrels. Males are larger than females, but otherwise the sexes look similar. Adults measure 17–32 inches in length, with the tail averaging 4–10 inches. Adult weight will vary widely through the year, ranging from 5 pounds in the early spring to 14 pounds in the fall. This is because they are deep hibernators and their weight will differ substantially between den entry and emergence. The woodchuck has coarse, reddish-brown fur grizzled with guard hairs that are gray with yellow tips; brown or black tail, legs, and feet; and a black face. Melanistic (black) animals occur but are uncommon. Woodchucks have short powerful legs and short ears. Their incisor teeth grow continually and must be worn down when feeding or the tooth will grow to a length that injures or impairs the animal.
Woodchucks mate in March and April shortly after emergence from hibernation. They can first breed as yearlings (i.e., in their second summer), however, only 20–40% of female yearlings do breed. The tiny, feeble young are born in the burrows after a gestation period of 30–32 days. The litter size averages 3–5 pups, which emerge from the den at about 33 days and are weaned at about 42 days. Woodchucks are typically daytime animals. During most of the year, their activity peaks in mid-morning and again in the late afternoon, but declines at midday. Early and late in the season they may be active only in the afternoon. They enter hibernation in late fall and emerge in early spring. Their home range is determined by food availability, but is typically between .75–2.25 acres. Home ranges of adult males may overlap those of females, but usually not those of other males. Woodchucks disperse from their birth area when less than 1 year old; females traveling about .25 of a mile and males slightly less than a mile. Woodchucks are quite wary and remain on the alert around their burrow entrance and while feeding.
Food, habits, and habitat
Woodchucks are generalist plant feeders, consuming a wide variety of herbaceous vegetation, including clover, wild lettuce, grasses, chickweed, and dandelion. They also eat hay grasses, alfalfa, corn, and a variety of common garden or commercial crops. Woodchucks readily climb trees and may feed on leaves of certain species, such as mulberry. They also gnaw woody stems or trees, primarily in spring.Woodchucks are an “edge” species, living in hedgerows or brush clumps along old fields, pastures, or croplands intermixed with small woodlands. Burrows are dug in well-drained soil along woodland edges and brushy hedgerows, often on rather steep slopes. The animal will also burrow under sheds, porches, decks, or walkways. Burrows are a critical feature of their lifestyle, and typically include multiple entrances. The main shaft may be up to 50 feet in length, with many side passages. Woodchucks usually pile up a mound of dirt and rocks at the burrow entrance, but the entry may otherwise be well-concealed.
Tips for residents
Woodchuck damage to vegetable or flower gardens is difficult to control. When populations are high and food sources are abundant, new woodchucks will quickly replace those that have been eliminated. To avoid or reduce damage and make your property less attractive to woodchucks, consider the following options.
Fencing can help alleviate woodchuck damage, but woodchucks are good climbers, so fences should be at least 3 feet high, constructed of heavy chicken wire or 2-inch mesh welded wire. Bury the lower edge 10–12 inches deep to prevent them from burrowing under it. An electric wire 4–5 inches off the ground and 4–5 inches from the fence, powered by an approved fence charger, will discourage woodchucks from climbing. Electrified netting is also effective. As an alternative, bend the top 15 inches of the fence outward at a 45° angle.
Close off structures
Woodchucks may burrow under sheds, porches, walkways, or other structures. Be proactive and securely block up all possible crevices, cracks, and holes prior to any use by woodchucks. Boards, fencing, or stones may have to extend 12 inches or more into the ground to prevent tunneling. Be careful not to block such places when woodchucks may be trapped inside.
Commercial animal repellents have been used to deter woodchucks from gardens, generally with minimal success. It is illegal to use poisons to eliminate wildlife, even if the animals are in a building. Woodchucks may only be sickened by poisons, and dead, poisoned woodchucks may cause secondary poisoning of raptors, domestic pets, and other scavengers.
Woodchucks may be killed in their burrows with commercial gas cartridges that produce carbon monoxide and other gases. Find the main burrow entrance and all secondary holes. Block all holes except the main one with a chunk of sod. Ignite the cartridge, throw it down the hole, and block up the hole. Watch for smoke emissions, which indicate a poor seal. Follow all directions on the cartridge.
Trapping and shooting
Woodchucks can be captured in wire cage traps placed at the main burrow entrance or in travel ways. Apple slices, carrots, or cantaloupe are good baits. If food is abundant, woodchucks may be reluctant to enter traps. Any trapped animal must either be relocated on the premises or destroyed humanely; it is illegal to transport and release wildlife to another location. Shooting is quick, simple, and effective in areas where firearm discharge is safe and legal. A .22 caliber rifle or a shotgun with #4–6 shot is suitable. This method may be most effective when targeting a few persistent animals. New woodchucks may replace those that have been removed.
If you are experiencing problems with woodchucks or have questions, contact your nearest Masswildlife office.