The woodchuck (Marmota monax), a member of the squirrel family, is also known as the “ground hog” or “whistle pig.” It is closely related to other species of North American marmots. It is usually grizzled brownish gray, but white (albino) and black (melanistic) individuals can occasionally be found. The woodchuck’s compact, chunky body is supported by short strong legs. Its forefeet have long, curved claws that are well adapted for digging burrows. Its tail is short, well furred, and dark brown.  Exclusion:  Buried welded or woven wire fences. Single-strand electric fences. Frightening Devices:  Scarecrows and other effigies. Repellents:  None are registered. Toxicants:  None are registered. Fumigants: Gas cartridges. Aluminum phosphide. Trapping: Live traps. No. 2 leghold traps. Conibear® traps. Shooting:  Effective where legal and safe

Bollengier,  Rene  M., Jr.

English

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln The Handbook: Prevention and Control of Wildlife Damage Wildlife Damage Management, Internet Center for July 1994 Woodchucks Rene M. Bollengier Jr. USDA-APHIS-Animal Damage Control, Concord, NH Follow this and additional works at: https://digitalcommons.unl.edu/icwdmhandbook  Part of the Environmental Sciences Commons Bollengier, Rene M. Jr., "Woodchucks" (1994). The Handbook: Prevention and Control of Wildlife Damage. 18. https://digitalcommons.unl.edu/icwdmhandbook/18 This Article is brought to you for free and open access by the Wildlife Damage Management, Internet Center for at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in The Handbook: Prevention and Control of Wildlife Damage by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. B-183WOODCHUCKSRene M. Bollengier, Jr.Assistant Regional Director (retired)USDA-APHIS-Animal Damage ControlConcord, New Hampshire 03302-2398Fig. 1. Woodchuck, Marmota monaxDamage Prevention andControl MethodsExclusionBuried welded or woven wire fences.Single-strand electric fences.Frightening DevicesScarecrows and other effigies.RepellentsNone are registered.ToxicantsNone are registered.FumigantsGas cartridges.Aluminum phosphide.TrappingLive traps.No. 2 leghold traps.Conibear® traps.ShootingEffective where legal and safe.IdentificationThe woodchuck (Marmota monax,  Fig.1), a member of the squirrel family, isalso known as the “ground hog” or“whistle pig.” It is closely related toother species of North American mar-mots. It is usually grizzled brownishgray, but white (albino) and black(melanistic) individuals can occasion-ally be found. The woodchuck’s com-pact, chunky body is supported byshort strong legs. Its forefeet havelong, curved claws that are welladapted for digging burrows. Its tail isshort, well furred, and dark brown.PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994Cooperative Extension DivisionInstitute of Agriculture and Natural ResourcesUniversity of Nebraska - LincolnUnited States Department of AgricultureAnimal and Plant Health Inspection ServiceAnimal Damage ControlGreat Plains Agricultural CouncilWildlife CommitteeB-184Both sexes are similar in appearance,but the male is slightly larger, weigh-ing an average of 5 to 10 pounds (2.2 to4.5 kg). The total length of the headand body averages 16 to 20 inches (40to 51 cm). The tail is usually 4 to 7inches (10 to 18 cm) long. Like otherrodents, woodchucks have white oryellowish-white, chisel-like incisorteeth. Their eyes, ears, and nose arelocated toward the top of the head,which allows them to remain con-cealed in their burrows while theycheck for danger over the rim or edge.Although they are slow runners,woodchucks are alert and scurryquickly to their dens when they sensedanger.RangeWoodchucks occur throughout easternand central Alaska, British Columbia,and most of southern Canada. Theirrange in the United States extendsthroughout the East, northern Idaho,northeastern North Dakota, southeast-ern Nebraska, eastern Kansas, andnortheastern Oklahoma, as well assouth to Virginia and northern Ala-bama (Fig. 2).HabitatIn general, woodchucks prefer openfarmland and the surroundingwooded or brushy areas adjacent toopen land. Burrows commonly arelocated in fields and pastures, alongfence rows, stone walls, roadsides, andnear building foundations or the basesof trees. Burrows are almost alwaysfound in or near open, grassy mead-ows or fields. Woodchuck burrows aredistinguished by a large mound ofexcavated earth at the main entrance.The main opening is approximately 10to 12 inches (25 to 30 cm) in diameter.There are two or more entrances toeach burrow system. Some secondaryentrances are dug from below theground and do not have mounds ofearth beside them. They are usuallywell hidden and sometimes difficult tolocate (Fig. 3). During spring, activeburrows can be located by the freshlyexcavated earth at the main entrance.The burrow system serves as home tothe woodchuck for mating, weaningyoung, hibernating in winter, and pro-tection when threatened.Food HabitsWoodchucks prefer to feed in the earlymorning and evening hours. They arestrict herbivores and feed on a varietyof vegetables, grasses, and legumes.Preferred foods include soybeans,beans, peas, carrot tops, alfalfa, clover,and grasses.General Biology,Reproduction, andBehaviorWoodchucks are primarily activeduring daylight hours. When not feed-ing, they sometimes bask in the sunduring the warmest periods of theday. They have been observed dozingon fence posts, stone walls, large rocks,and fallen logs close to the burrowentrance. Woodchucks are goodclimbers and sometimes are seen inlower tree branches.Woodchucks are among the few mam-mals that enter into true hibernation.Hibernation generally starts in late fall,near the end of October or earlyNovember, but varies with latitude. Itcontinues until late February andMarch. In northern latitudes, torporcan start earlier and end later. Malesusually come out of hibernation beforefemales and subadults.Males may travel long distances, andoccasionally at night, in search of amate. Woodchucks breed in Marchand April. A single litter of 2 to 6 (usu-ally 4) young is produced each seasonafter a gestation period of about 32days. The young are born blind andhairless. They are weaned by late Juneor early July, and soon after strike outon their own. They frequently occupyabandoned dens or burrows. Thenumerous new burrows that appearduring late summer are generally dugFig. 3. Burrow system of the woodchuck.Side entranceNestchamberMainentranceFig. 2. Range of the woodchuck in North America.B-185by older woodchucks. The life span ofa woodchuck is about 3 to 6 years.Woodchucks usually range only 50 to150 feet (15 to 30 m) from their denduring the daytime. This distance mayvary, however, during the mating sea-son or based on the availability offood. Woodchucks maintain sanitaryden sites and burrow systems, replac-ing nest materials frequently. A bur-row and den system is often used forseveral seasons. The tunnel system isirregular and may be extensive in size.Burrows may be as deep as 5 feet (1.5m) and range from 8 to 66 feet (2.4 to19.8 m) in total length (Fig. 3). Old bur-rows not in use by woodchucks pro-vide cover for rabbits, weasels, andother wildlife.When startled, a woodchuck may emita shrill whistle or alarm, preceded by alow, abrupt “phew.” This is followedby a low, rapid warble that soundslike “tchuck, tchuck.” The call is usu-ally made when the animal is startledat the entrance of the burrow. The pri-mary predators of woodchucksinclude hawks, owls, foxes, coyotes,bobcats, weasels, dogs, and humans.Many woodchucks are killed on roadsby automobiles.DamageOn occasion, the woodchuck’s feedingand burrowing habits conflict withhuman interests. Damage often occurson farms, in home gardens, orchards,nurseries, around buildings, andsometimes around dikes. Damage tocrops such as alfalfa, soybeans, beans,squash, and peas can be costly andextensive. Fruit trees and ornamentalshrubs are damaged by woodchucksas they gnaw or claw woody vegeta-tion. Gnawing on underground powercables has caused electrical outages.Damage to rubber hoses in vehicles,such as those used for vacuum andfuel lines, has also been documented.Mounds of earth from the excavatedburrow systems and holes formed atburrow entrances present a hazard tofarm equipment, horses, and riders.On occasion, burrowing can weakendikes and foundations.Legal StatusIn most states, woodchucks are consid-ered game animals. There is usually nobag limit or closed season. In damagesituations, woodchucks are usually notprotected. The status may vary fromstate to state, depending on the controltechnique to be employed. Consultwith your state wildlife department,USDA-APHIS-Animal Damage Con-trol representative, or extension agentbefore shooting and/or trapping prob-lem individuals.Damage Prevention andControl MethodsExclusionFencing can help reduce woodchuckdamage. Woodchucks, however, aregood climbers and can easily scalewire fences if precautions are nottaken. Fences should be at least 3 feet(1 m) high and made of heavy poultrywire or 2-inch (5-cm) mesh wovenwire. To prevent burrowing under thefence, bury the lower edge 10 to 12inches (25 to 30 cm) in the ground orbend the lower edge at an L-shapedangle leading outward and bury it inthe ground 1 to 2 inches (2.5 to 5 cm).Fences should extend 3 to 4 feet (0.9 to1.2 m) above the ground. Place an elec-tric wire 4 to 5 inches (10 to 13 cm) offthe ground and the same distance out-side the fence. When connected to aUL-approved fence charger, the elec-tric wire will prevent climbing andburrowing. Bending the top 15 inches(38 cm) of wire fence outward at a 45oangle will also prevent climbing overthe fence. Fencing is most useful inprotecting home gardens and has theadded advantage of keeping rabbits,dogs, cats, and other animals out ofthe garden area. In some instances, anelectric wire alone, placed 4 to 5 inches(10 to 13 cm) above the ground, hasdeterred woodchucks from enteringgardens. Vegetation in the vicinity ofany electric fence should be removedregularly to prevent the system fromshorting out.Frightening DevicesScarecrows and other effigies can pro-vide temporary relief from woodchuckdamage. Move them regularly andincorporate a high level of humanactivity in the susceptible area.RepellentsNone are registered.ToxicantsNone are registered for woodchuckcontrol.FumigantsGas cartridge (carbon monoxide).The most common means of wood-chuck control is the use of commercialgas cartridges. They are specially de-signed cardboard cylinders filled withslow-burning chemicals. They areignited and placed in burrow systems,and all entrances are sealed. As the gascartridges burn, they produce carbonmonoxide and other gases that arelethal to woodchucks. Gas cartridgesare a General Use Pesticide and areavailable from local farm supplystores, certain USDA-APHIS-ADCstate and district offices, and theUSDA-APHIS-ADC Pocatello SupplyDepot. Directions for their use are onthe label and should be carefully readand closely followed (see informationon gas cartridges in the Pesticides andSupplies and Materials sections).Be careful when using gas cartridges.Do not use them in burrows locatedunder wooden sheds, buildings, ornear other combustible materialsbecause of the potential fire hazard.Gas cartridges are ignited by lighting afuse. They will not explode if properlyprepared and used. Caution should betaken to avoid prolonged breathing offumes.Each burrow system should be treatedin the following manner:1. Locate the main burrow opening(identified by a mound of excavatedsoil) and all other secondaryentrances associated with that bur-row system.B-1862. With a spade, cut a clump of sodslightly larger than each opening.Place a piece of sod over eachentrance except the main entrance.Leave a precut sod clump next tothe main entrance for later use.3. Prepare the gas cartridge for igni-tion and placement following thewritten instructions on the label.4. Kneel at the main burrow opening,light the fuse, and immediatelyplace (do not throw) the cartridgeas far down the hole as possible.5. Immediately after positioning theignited cartridge in the burrow,close the main opening or all open-ings, if necessary, by placing thepieces of precut sod, grass sidedown, over the opening. Placing thesod with the grass side down pre-vents smothering the lit cartridge.Make a tight seal by packing loosesoil over the piece of sod. Lookcarefully for smoke leaking from theburrow system and cover or resealany openings that leak.6. Continue to observe the site for 4 to5 minutes and watch nearby holes.Continue to reseal those from whichsmoke is escaping.7. Repeat these steps until all burrowsystems have been treated in prob-lem areas.Burrows can be treated with gas car-tridges at any time. This method is mosteffective in the spring before the youngemerge. On occasion, treated burrowswill be reopened by another animalreoccupying the burrow system. If thisoccurs, retreatment may be necessary.Aluminum Phosphide. Aluminumphosphide is a Restricted Use Pesticideand can be applied only by a certifiedpesticide applicator. Treatment of bur-row systems is relatively easy. Placetwo to four tablets deep into the mainburrow. Plug the burrow openingswith crumpled newspapers and thenpack the openings with loose soil. Allburrows must be sealed tightly butavoid covering the tablets with soil.The treatment site should be inspected24 to 48 hours later and opened bur-rows should be retreated.Aluminum phosphide in the presenceof moisture in the burrow produceshydrogen phosphide (phosphine) gas.Therefore, soil moisture and a tightlysealed burrow system are important.The tablets are presently approved foroutdoor use on noncropland andorchards for burrowing rodents. Tab-lets should not be used within 15 feet(5 m) of any occupied building orstructure or where gases could escapeinto areas occupied by other animalsor humans. Storage of unused tabletsis critical — they must be kept in theiroriginal container, in a cool, dry,locked, and ventilated room. Theymust be protected from moisture,open flames, and heat.The legal application and use of alumi-num phosphide for woodchuck con-trol may vary from state to state.Check with your state pesticide regis-tration board, USDA-APHIS-ADCrepresentative, or extension agentwhen considering use of this material.Aluminum phosphide should alwaysbe applied as directed on the label.TrappingSteel leghold and live traps. Trapsmay also be used to reduce wood-chuck damage, especially in or nearbuildings. Both steel leghold and livetraps are effective. Trapping should beused in areas where gas cartridges oraluminum phosphide may create a firehazard or where fumes may enterareas to be protected. Woodchucks arestrong animals and a No. 2 steel trapis needed to hold them. Before usingsteel traps, consult your state wildlifedepartment or USDA-APHIS-ADCrepresentative for trapping regula-tions. Steel traps should not beemployed in areas where there is apossibility of capturing pets orlivestock.Live trapping can sometimes be diffi-cult, but is effective. Live traps can bebuilt at home, purchased from com-mercial sources (see Supplies andMaterials), or borrowed. Bait trapswith apple slices or vegetables such ascarrots and lettuce, and change baitsdaily. Locate traps at main entrancesor major travel lanes. Place guide logson either side of the path between theburrow opening and the trap to helpfunnel the animal into the trap. Checkall traps twice daily, morning andevening, so that captured animals maybe quickly removed. A captured ani-mal can be relocated to an area withsuitable habitat where no additionaldamage can be caused. The animal canalso be euthanized by lethal injection(by a veterinarian or under veterinar-ian supervision), by shooting, or bycarbon dioxide gas.Conibear® traps. Conibear® traps areeffective in some situations. A set in atravelway, such as between a woodpile and barn, can be very effective.Sets can also be made at the mainentrance of the burrow system. Logs,sticks, stones, and boards should beused to block travelways around theset and/or to lead the animal into theset. No bait is necessary for Conibear®sets. Conibear® 110s, 160s, and 220sare best suited for woodchuck control.Conibears® are well suited for use nearor under structures in which fumi-gants and shooting present a hazard.Conibear® 110s will handle young,small animals, while 160s and 220s willalso handle larger adults.Conibear® traps kill the animal quicklyand care should be taken to avoidtrapping domestic animals such as catsand dogs. Some state or local laws pro-hibit the use of Conibear® traps exceptin water. Consult your state wildlifedepartment or USDA-APHIS-ADCoffice for regulations.ShootingIn many states, woodchucks are con-sidered game animals. Therefore, ifshooting is permitted, a valid statehunting license may be required. Insome states there is no closed season,nor is there usually any limit on thenumber of woodchucks that can betaken by hunters. If shooting can beaccomplished safely, landownersand/or hunters can reduce or maintaina low population of woodchuckswhere necessary. Landowners andhunters should agree on huntingarrangements prior to initiating anyshooting activities. Another alternativeB-187would be to have a professionalUSDA-APHIS-ADC representative dothe job. He or she will be familiar withlegalities and techniques. Contractingwith a Animal Damage Control pro-fessional would be especially valuablewhen and where large numbers ofwoodchucks are causing serious eco-nomic losses. Shooting can be used asa follow-up to other, more substantialcontrol activities.Rifles with telescopic sights are com-monly used in the sport shooting ofwoodchucks. A variety of calibers canbe used, but .22-caliber centerfire riflesare most popular. Occasionally, shot-guns are used to eliminate wood-chucks that are causing damage. Theobjective is to remove the animal ashumanely as possible without wound-ing it. Shotgun gauge, range, and shotsize should be considered when usingthis method. Use a 12-gauge with No.4 to No. 6 shot. The range should bewithin 25 yards (23 m).Carefully assess the area behind andaround the target for safety. Pellets canricochet, causing injury or seriousdamage in background areas. Use of arifle or shotgun should be conductedonly if good shooting conditions exist.AcknowledgmentsI thank the state directors of USDA-APHIS-ADC, whose comments and editing improvedthis publication.Figures 1 through 3 from Schwartz andSchwartz (1981), adapted by Jill Sack Johnson.For AdditionalInformationBurt, W. H., and R. P. Grossenheider. 1976. Afield guide to the mammals. 3d ed.Houghton Mifflin Co., Boston. 289 pp.Lee, D. S., and J. B. Funderburg. 1982. Marmots.Pages 176-191 in J. A. Chapman and G. A.Feldhamer, eds. Wild mammals of NorthAmerica: biology, management, andeconomics. The Johns Hopkins Univ. Press,Baltimore, Maryland.Marsh, R. E., and W. E. Howard. 1990.Vertebrate pests. Pages 791-861 in A. Mallis,ed. Handbook of pest control, 7th ed.Franzak and Foster Co., Cleveland, Ohio.Schwartz, C. W., and E. R. Schwartz. 1981. Thewild mammals of Missouri. Rev. ed. Univ.Missouri Press, Columbia. 356 pp.Whitaker, J. O. Jr. 1980. Audubon Society fieldguide to North American mammals. 6th ed.Alfred A. Knopf, Inc. New York.EditorsScott E. HygnstromRobert M. TimmGary E. Larson

Woodchucks

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
The Handbook: Prevention and Control of 
Wildlife Damage 
Wildlife Damage Management, Internet Center 
for 
July 1994 
Woodchucks 
Rene M. Bollengier Jr. 
USDA-APHIS-Animal Damage Control, Concord, NH 
Follow this and additional works at: https://digitalcommons.unl.edu/icwdmhandbook 
 Part of the Environmental Sciences Commons 
Bollengier, Rene M. Jr., "Woodchucks" (1994). The Handbook: Prevention and Control of Wildlife Damage. 
18. 
https://digitalcommons.unl.edu/icwdmhandbook/18 
This Article is brought to you for free and open access by the Wildlife Damage Management, Internet Center for at 
DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in The Handbook: Prevention 
and Control of Wildlife Damage by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 
B-183
WOODCHUCKSRene M. Bollengier, Jr.Assistant Regional Director (retired)
USDA-APHIS-
Animal Damage Control
Concord, New Hampshire 03302-2398
Fig. 1. Woodchuck, Marmota monax
Damage Prevention and
Control Methods
Exclusion
Buried welded or woven wire fences.
Single-strand electric fences.
Frightening Devices
Scarecrows and other effigies.
Repellents
None are registered.
Toxicants
None are registered.
Fumigants
Gas cartridges.
Aluminum phosphide.
Trapping
Live traps.
No. 2 leghold traps.
Conibear® traps.
Shooting
Effective where legal and safe.
Identification
The woodchuck (Marmota monax,  Fig.
1), a member of the squirrel family, is
also known as the “ground hog” or
“whistle pig.” It is closely related to
other species of North American mar-
mots. It is usually grizzled brownish
gray, but white (albino) and black
(melanistic) individuals can occasion-
ally be found. The woodchuck’s com-
pact, chunky body is supported by
short strong legs. Its forefeet have
long, curved claws that are well
adapted for digging burrows. Its tail is
short, well furred, and dark brown.
PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994
Cooperative Extension Division
Institute of Agriculture and Natural Resources
University of Nebraska - Lincoln
United States Department of Agriculture
Animal and Plant Health Inspection Service
Animal Damage Control
Great Plains Agricultural Council
Wildlife Committee
B-184
Both sexes are similar in appearance,
but the male is slightly larger, weigh-
ing an average of 5 to 10 pounds (2.2 to
4.5 kg). The total length of the head
and body averages 16 to 20 inches (40
to 51 cm). The tail is usually 4 to 7
inches (10 to 18 cm) long. Like other
rodents, woodchucks have white or
yellowish-white, chisel-like incisor
teeth. Their eyes, ears, and nose are
located toward the top of the head,
which allows them to remain con-
cealed in their burrows while they
check for danger over the rim or edge.
Although they are slow runners,
woodchucks are alert and scurry
quickly to their dens when they sense
danger.
Range
Woodchucks occur throughout eastern
and central Alaska, British Columbia,
and most of southern Canada. Their
range in the United States extends
throughout the East, northern Idaho,
northeastern North Dakota, southeast-
ern Nebraska, eastern Kansas, and
northeastern Oklahoma, as well as
south to Virginia and northern Ala-
bama (Fig. 2).
Habitat
In general, woodchucks prefer open
farmland and the surrounding
wooded or brushy areas adjacent to
open land. Burrows commonly are
located in fields and pastures, along
fence rows, stone walls, roadsides, and
near building foundations or the bases
of trees. Burrows are almost always
found in or near open, grassy mead-
ows or fields. Woodchuck burrows are
distinguished by a large mound of
excavated earth at the main entrance.
The main opening is approximately 10
to 12 inches (25 to 30 cm) in diameter.
There are two or more entrances to
each burrow system. Some secondary
entrances are dug from below the
ground and do not have mounds of
earth beside them. They are usually
well hidden and sometimes difficult to
locate (Fig. 3). During spring, active
burrows can be located by the freshly
excavated earth at the main entrance.
The burrow system serves as home to
the woodchuck for mating, weaning
young, hibernating in winter, and pro-
tection when threatened.
Food Habits
Woodchucks prefer to feed in the early
morning and evening hours. They are
strict herbivores and feed on a variety
of vegetables, grasses, and legumes.
Preferred foods include soybeans,
beans, peas, carrot tops, alfalfa, clover,
and grasses.
General Biology,
Reproduction, and
Behavior
Woodchucks are primarily active
during daylight hours. When not feed-
ing, they sometimes bask in the sun
during the warmest periods of the
day. They have been observed dozing
on fence posts, stone walls, large rocks,
and fallen logs close to the burrow
entrance. Woodchucks are good
climbers and sometimes are seen in
lower tree branches.
Woodchucks are among the few mam-
mals that enter into true hibernation.
Hibernation generally starts in late fall,
near the end of October or early
November, but varies with latitude. It
continues until late February and
March. In northern latitudes, torpor
can start earlier and end later. Males
usually come out of hibernation before
females and subadults.
Males may travel long distances, and
occasionally at night, in search of a
mate. Woodchucks breed in March
and April. A single litter of 2 to 6 (usu-
ally 4) young is produced each season
after a gestation period of about 32
days. The young are born blind and
hairless. They are weaned by late June
or early July, and soon after strike out
on their own. They frequently occupy
abandoned dens or burrows. The
numerous new burrows that appear
during late summer are generally dug
Fig. 3. Burrow system of the woodchuck.
Side entrance
Nest
chamber
Main
entrance
Fig. 2. Range of the woodchuck in North America.
B-185
by older woodchucks. The life span of
a woodchuck is about 3 to 6 years.
Woodchucks usually range only 50 to
150 feet (15 to 30 m) from their den
during the daytime. This distance may
vary, however, during the mating sea-
son or based on the availability of
food. Woodchucks maintain sanitary
den sites and burrow systems, replac-
ing nest materials frequently. A bur-
row and den system is often used for
several seasons. The tunnel system is
irregular and may be extensive in size.
Burrows may be as deep as 5 feet (1.5
m) and range from 8 to 66 feet (2.4 to
19.8 m) in total length (Fig. 3). Old bur-
rows not in use by woodchucks pro-
vide cover for rabbits, weasels, and
other wildlife.
When startled, a woodchuck may emit
a shrill whistle or alarm, preceded by a
low, abrupt “phew.” This is followed
by a low, rapid warble that sounds
like “tchuck, tchuck.” The call is usu-
ally made when the animal is startled
at the entrance of the burrow. The pri-
mary predators of woodchucks
include hawks, owls, foxes, coyotes,
bobcats, weasels, dogs, and humans.
Many woodchucks are killed on roads
by automobiles.
Damage
On occasion, the woodchuck’s feeding
and burrowing habits conflict with
human interests. Damage often occurs
on farms, in home gardens, orchards,
nurseries, around buildings, and
sometimes around dikes. Damage to
crops such as alfalfa, soybeans, beans,
squash, and peas can be costly and
extensive. Fruit trees and ornamental
shrubs are damaged by woodchucks
as they gnaw or claw woody vegeta-
tion. Gnawing on underground power
cables has caused electrical outages.
Damage to rubber hoses in vehicles,
such as those used for vacuum and
fuel lines, has also been documented.
Mounds of earth from the excavated
burrow systems and holes formed at
burrow entrances present a hazard to
farm equipment, horses, and riders.
On occasion, burrowing can weaken
dikes and foundations.
Legal Status
In most states, woodchucks are consid-
ered game animals. There is usually no
bag limit or closed season. In damage
situations, woodchucks are usually not
protected. The status may vary from
state to state, depending on the control
technique to be employed. Consult
with your state wildlife department,
USDA-APHIS-Animal Damage Con-
trol representative, or extension agent
before shooting and/or trapping prob-
lem individuals.
Damage Prevention and
Control Methods
Exclusion
Fencing can help reduce woodchuck
damage. Woodchucks, however, are
good climbers and can easily scale
wire fences if precautions are not
taken. Fences should be at least 3 feet
(1 m) high and made of heavy poultry
wire or 2-inch (5-cm) mesh woven
wire. To prevent burrowing under the
fence, bury the lower edge 10 to 12
inches (25 to 30 cm) in the ground or
bend the lower edge at an L-shaped
angle leading outward and bury it in
the ground 1 to 2 inches (2.5 to 5 cm).
Fences should extend 3 to 4 feet (0.9 to
1.2 m) above the ground. Place an elec-
tric wire 4 to 5 inches (10 to 13 cm) off
the ground and the same distance out-
side the fence. When connected to a
UL-approved fence charger, the elec-
tric wire will prevent climbing and
burrowing. Bending the top 15 inches
(38 cm) of wire fence outward at a 45o
angle will also prevent climbing over
the fence. Fencing is most useful in
protecting home gardens and has the
added advantage of keeping rabbits,
dogs, cats, and other animals out of
the garden area. In some instances, an
electric wire alone, placed 4 to 5 inches
(10 to 13 cm) above the ground, has
deterred woodchucks from entering
gardens. Vegetation in the vicinity of
any electric fence should be removed
regularly to prevent the system from
shorting out.
Frightening Devices
Scarecrows and other effigies can pro-
vide temporary relief from woodchuck
damage. Move them regularly and
incorporate a high level of human
activity in the susceptible area.
Repellents
None are registered.
Toxicants
None are registered for woodchuck
control.
Fumigants
Gas cartridge (carbon monoxide).
The most common means of wood-
chuck control is the use of commercial
gas cartridges. They are specially de-
signed cardboard cylinders filled with
slow-burning chemicals. They are
ignited and placed in burrow systems,
and all entrances are sealed. As the gas
cartridges burn, they produce carbon
monoxide and other gases that are
lethal to woodchucks. Gas cartridges
are a General Use Pesticide and are
available from local farm supply
stores, certain USDA-APHIS-ADC
state and district offices, and the
USDA-APHIS-ADC Pocatello Supply
Depot. Directions for their use are on
the label and should be carefully read
and closely followed (see information
on gas cartridges in the Pesticides and
Supplies and Materials sections).
Be careful when using gas cartridges.
Do not use them in burrows located
under wooden sheds, buildings, or
near other combustible materials
because of the potential fire hazard.
Gas cartridges are ignited by lighting a
fuse. They will not explode if properly
prepared and used. Caution should be
taken to avoid prolonged breathing of
fumes.
Each burrow system should be treated
in the following manner:
1. Locate the main burrow opening
(identified by a mound of excavated
soil) and all other secondary
entrances associated with that bur-
row system.
B-186
2. With a spade, cut a clump of sod
slightly larger than each opening.
Place a piece of sod over each
entrance except the main entrance.
Leave a precut sod clump next to
the main entrance for later use.
3. Prepare the gas cartridge for igni-
tion and placement following the
written instructions on the label.
4. Kneel at the main burrow opening,
light the fuse, and immediately
place (do not throw) the cartridge
as far down the hole as possible.
5. Immediately after positioning the
ignited cartridge in the burrow,
close the main opening or all open-
ings, if necessary, by placing the
pieces of precut sod, grass side
down, over the opening. Placing the
sod with the grass side down pre-
vents smothering the lit cartridge.
Make a tight seal by packing loose
soil over the piece of sod. Look
carefully for smoke leaking from the
burrow system and cover or reseal
any openings that leak.
6. Continue to observe the site for 4 to
5 minutes and watch nearby holes.
Continue to reseal those from which
smoke is escaping.
7. Repeat these steps until all burrow
systems have been treated in prob-
lem areas.
Burrows can be treated with gas car-
tridges at any time. This method is most
effective in the spring before the young
emerge. On occasion, treated burrows
will be reopened by another animal
reoccupying the burrow system. If this
occurs, retreatment may be necessary.
Aluminum Phosphide. Aluminum
phosphide is a Restricted Use Pesticide
and can be applied only by a certified
pesticide applicator. Treatment of bur-
row systems is relatively easy. Place
two to four tablets deep into the main
burrow. Plug the burrow openings
with crumpled newspapers and then
pack the openings with loose soil. All
burrows must be sealed tightly but
avoid covering the tablets with soil.
The treatment site should be inspected
24 to 48 hours later and opened bur-
rows should be retreated.
Aluminum phosphide in the presence
of moisture in the burrow produces
hydrogen phosphide (phosphine) gas.
Therefore, soil moisture and a tightly
sealed burrow system are important.
The tablets are presently approved for
outdoor use on noncropland and
orchards for burrowing rodents. Tab-
lets should not be used within 15 feet
(5 m) of any occupied building or
structure or where gases could escape
into areas occupied by other animals
or humans. Storage of unused tablets
is critical — they must be kept in their
original container, in a cool, dry,
locked, and ventilated room. They
must be protected from moisture,
open flames, and heat.
The legal application and use of alumi-
num phosphide for woodchuck con-
trol may vary from state to state.
Check with your state pesticide regis-
tration board, USDA-APHIS-ADC
representative, or extension agent
when considering use of this material.
Aluminum phosphide should always
be applied as directed on the label.
Trapping
Steel leghold and live traps. Traps
may also be used to reduce wood-
chuck damage, especially in or near
buildings. Both steel leghold and live
traps are effective. Trapping should be
used in areas where gas cartridges or
aluminum phosphide may create a fire
hazard or where fumes may enter
areas to be protected. Woodchucks are
strong animals and a No. 2 steel trap
is needed to hold them. Before using
steel traps, consult your state wildlife
department or USDA-APHIS-ADC
representative for trapping regula-
tions. Steel traps should not be
employed in areas where there is a
possibility of capturing pets or
livestock.
Live trapping can sometimes be diffi-
cult, but is effective. Live traps can be
built at home, purchased from com-
mercial sources (see Supplies and
Materials), or borrowed. Bait traps
with apple slices or vegetables such as
carrots and lettuce, and change baits
daily. Locate traps at main entrances
or major travel lanes. Place guide logs
on either side of the path between the
burrow opening and the trap to help
funnel the animal into the trap. Check
all traps twice daily, morning and
evening, so that captured animals may
be quickly removed. A captured ani-
mal can be relocated to an area with
suitable habitat where no additional
damage can be caused. The animal can
also be euthanized by lethal injection
(by a veterinarian or under veterinar-
ian supervision), by shooting, or by
carbon dioxide gas.
Conibear® traps. Conibear® traps are
effective in some situations. A set in a
travelway, such as between a wood
pile and barn, can be very effective.
Sets can also be made at the main
entrance of the burrow system. Logs,
sticks, stones, and boards should be
used to block travelways around the
set and/or to lead the animal into the
set. No bait is necessary for Conibear®
sets. Conibear® 110s, 160s, and 220s
are best suited for woodchuck control.
Conibears® are well suited for use near
or under structures in which fumi-
gants and shooting present a hazard.
Conibear® 110s will handle young,
small animals, while 160s and 220s will
also handle larger adults.
Conibear® traps kill the animal quickly
and care should be taken to avoid
trapping domestic animals such as cats
and dogs. Some state or local laws pro-
hibit the use of Conibear® traps except
in water. Consult your state wildlife
department or USDA-APHIS-ADC
office for regulations.
Shooting
In many states, woodchucks are con-
sidered game animals. Therefore, if
shooting is permitted, a valid state
hunting license may be required. In
some states there is no closed season,
nor is there usually any limit on the
number of woodchucks that can be
taken by hunters. If shooting can be
accomplished safely, landowners
and/or hunters can reduce or maintain
a low population of woodchucks
where necessary. Landowners and
hunters should agree on hunting
arrangements prior to initiating any
shooting activities. Another alternative
B-187
would be to have a professional
USDA-APHIS-ADC representative do
the job. He or she will be familiar with
legalities and techniques. Contracting
with a Animal Damage Control pro-
fessional would be especially valuable
when and where large numbers of
woodchucks are causing serious eco-
nomic losses. Shooting can be used as
a follow-up to other, more substantial
control activities.
Rifles with telescopic sights are com-
monly used in the sport shooting of
woodchucks. A variety of calibers can
be used, but .22-caliber centerfire rifles
are most popular. Occasionally, shot-
guns are used to eliminate wood-
chucks that are causing damage. The
objective is to remove the animal as
humanely as possible without wound-
ing it. Shotgun gauge, range, and shot
size should be considered when using
this method. Use a 12-gauge with No.
4 to No. 6 shot. The range should be
within 25 yards (23 m).
Carefully assess the area behind and
around the target for safety. Pellets can
ricochet, causing injury or serious
damage in background areas. Use of a
rifle or shotgun should be conducted
only if good shooting conditions exist.
Acknowledgments
I thank the state directors of USDA-APHIS-
ADC, whose comments and editing improved
this publication.
Figures 1 through 3 from Schwartz and
Schwartz (1981), adapted by Jill Sack Johnson.
For Additional
Information
Burt, W. H., and R. P. Grossenheider. 1976. A
field guide to the mammals. 3d ed.
Houghton Mifflin Co., Boston. 289 pp.
Lee, D. S., and J. B. Funderburg. 1982. Marmots.
Pages 176-191 in J. A. Chapman and G. A.
Feldhamer, eds. Wild mammals of North
America: biology, management, and
economics. The Johns Hopkins Univ. Press,
Baltimore, Maryland.
Marsh, R. E., and W. E. Howard. 1990.
Vertebrate pests. Pages 791-861 in A. Mallis,
ed. Handbook of pest control, 7th ed.
Franzak and Foster Co., Cleveland, Ohio.
Schwartz, C. W., and E. R. Schwartz. 1981. The
wild mammals of Missouri. Rev. ed. Univ.
Missouri Press, Columbia. 356 pp.
Whitaker, J. O. Jr. 1980. Audubon Society field
guide to North American mammals. 6th ed.
Alfred A. Knopf, Inc. New York.
Editors
Scott E. Hygnstrom
Robert M. Timm
Gary E. Larson


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