Sanford D. Schemnitz Professor of Wildlife Science New Mexico State University PORCUPINES Las Cruces, New Mexico 88003 Fig. 1. Porcupine, Erethizon dorsatum Damage Prevention and Fumigants Identification Control Methods None are registered. Porcupines (Erethizon dorsatum), some- Exclusion Trapping times called “porkies” or “quill pigs,” (Fig. 1) are heavy-bodied, short- Fences (small areas). Steel leghold trap (No. 2 or 3). legged, slow, and awkward rodents, Tree trunk guards. Body-gripping (Conibear®) trap with a waddling gait. Adults are typi- (No. 220 or 330). cally 25 to 30 inches (64 to 76 cm) long Cultural Methods and weigh 10 to 30 pounds (4.5 to 13.5 Box trap. Encourage closed-canopy forest kg). They rely on their sharp, barbed stands. Shooting quills (up to 30,000 per individual) for defense. Repellents Day shooting and spotlighting are effective where legal. None are registered. Other Methods Some wood preservatives may incidentally repel porcupines. Encourage natural predators. Toxicants None are registered. 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 B-81 Great Plains Agricultural Council Wildlife Committee Range and Habitat not unusual. How the quills are maneuvered through the coyote’s The porcupine is a common resident of gastrointestinal tract is a mystery. the coniferous forests of western and northern North America (Fig. 2). It Porcupines are active year-round and wanders widely and is found from are primarily nocturnal, often resting cottonwood stands along prairie river in trees during the day. They favor bottoms and deserts to alpine tundra. caves, rock slides, and thick timber downfalls for shelter. Damage and Damage Identification Clipped twigs on fresh snow, tracks, and gnawings on trees are useful means of damage identification (Fig. 3). Trees are often deformed from par- tial girdling. Porcupines clip twigs and ab branches that fall to the ground or onto snow and often provide food for deer and other mammals. The consid- Fig. 3. Porcupine sign: a) tracks showing drag erable secondary effects of their feed- marks of tail; b) toothmarks on tree limbs. ing come from exposing the tree sapwood to attack by disease, insects, 18-inch-high (46-cm) poultry wire. A Fig. 2. Range of the porcupine in North America. and birds. This exposure is important 4- to 6-inch (10- to 15-cm) electric fence to many species of wildlife because can be enhanced by painting molasses diseased or hollow trees provide shel- on the wire. Porcupines will climb Food Habits ter and nest sites. fences, but an overhanging wire strip around the top of the fence at a 65o Porcupines occasionally will cause Porcupines eat herbaceous plants, angle to the upright wire will discour- considerable losses by damaging inner tree bark, twigs, and leaves, with age them. fruits, sweet corn, alfalfa, and small an apparent preference for ponderosa grains. They chew on hand tools and Completely enclose small trees with pine, aspen, willow, and cottonwood. other wood objects while seeking salt. wire baskets or encircle the trunks of Trees with thin, smooth bark are pre- They destroy siding on cabins when fruit and ornamental trees with 30-inch ferred over those with thick, rough seeking plywood resins. (70-cm) bands of aluminum flashing to bark. Porcupine feeding is frequently reduce damage. evident and has considerable impact Porcupines offer a considerable threat on the cottonwood stands of western to dogs, which never seem to learn to Cultural Methods river bottoms. avoid them. Domestic stock occasion- Thinned forest stands are vulnerable ally will nuzzle a porcupine and may to porcupine damage because lower be fatally injured if quills are not General Biology, vegetation can thrive. Porcupine popu- removed promptly. Reproduction, and lations are usually lower in closed Behavior canopy stands where understory veg- Legal Status etation is scant. Porcupines breed in autumn, and after Repellents a 7-month gestation period usually Porcupines are considered nongame produce 1 offspring in spring. animals and are not protected. Thiram is registered as a squirrel and Although the young are capable of rabbit repellent and may incidentally eating vegetation within a week after Damage Prevention and repel porcupines. This material is birth, they generally stay with the sprayed or painted on the plants sub- female through the summer. Juvenile Control Methods ject to damage. It must be renewed survival rates are high. Exclusion occasionally to remain effective. Com- mon wood preservatives may repel Predators of porcupines include Fencing small tree plantings, orchards, porcupines when applied to exterior coyotes, bobcats, mountain lions, black and gardens is effective in reducing plywoods. Avoid using wood preser- bears, fishers, martens, great horned porcupine damage. Electric fences are vatives that are metal-salt solutions. owls, and others. Coyote scats (feces) effective when the smooth electric wire These will attract porcupines. containing large numbers of quills are is placed 1 1/2 inches (3.8 cm) above B-82 Toxicants porcupines are active and can be Acknowledgments tracked in the snow and shot with a No toxicants can be legally used to .22-caliber rifle or pistol. Porcupines Some of the information for this chapter was control porcupines. taken from a chapter by Major L. Boddicker in often congregate around good denning the 1980 edition of Prevention and Control of Wild- Trapping sites and extensively girdle trees in the life Damage. area. In such places large numbers Steel leghold traps of size No. 2 or 3 Figure 1 by Emily Oseas Routman. may be taken by shooting. can be used to catch porcupines where Figure 2 adapted from Burt and Grossenheider legal. Cubby sets with salt baits, trail Other Considerations (1976) by Jill Sack Johnson. sets in front of dens, and coyote urine Porcupines are mobile and continually Figure 3 adapted from Murie (1954) by Renee scent post sets near dens and damage reinvade control areas. Complete con- Lanik, University of Nebraska-Lincoln. activity are effective. Scent post and trol is not desirable since it would re- trail sets must be checked daily to For Additional quire complete removal of porcupines. release nontarget animals that might Information Try to limit lethal porcupine control to be caught. Leghold traps should be individual animals causing damage by Burt, W. H., and R. P. Grossenheider. 1976. A bedded, firmly placed and leveled, fencing and management of the plant field guide to the mammals, 3d ed. and offset slightly to the side of the species. In areas of high porcupine Houghton Mifflin Co., Boston. 289 pp. trail. The trapped porcupine can be populations, plant ornamentals that Clark, J. P. 1986. Vertebrate pest control shot or killed by a sharp blow to the are not preferred foods. Intensive handbook. California Dep. Food and Agric. head. Sacramento. 615 pp. predator control may encourage por- The No. 220 or 330 Conibear® body- cupine population increases. Dodge, W. E. 1982. Porcupine. Pages 355-366 in gripping trap can be baited with a salt- J. A. Chapman and G. A. Feldhamer, eds. Wild mammals of North America: biology, soaked material or placed in den Economics of Damage management, and economics. The Johns entrances to catch and kill porcupines. and Control Hopkins Univ. Press. Baltimore. Care must be taken to avoid taking Marsh, R. E., and W. E. Howard. 1977. Verte- nontarget animals, since salt attracts Economic losses can be considerable brate control manual. Pest Control 45:28-31. many animals. The Conibear® trap from porcupines feeding on forest Murie, O. J. 1954. A field guide to animal tracks. does not allow the release of accidental plantings, ornamentals, and orchards Houghton Mifflin Co., Boston. 375 pp. catches. Some states do not allow the as well as on leather and other human Roze, V. 1989. The North American porcupine. use of No. 330 Conibear® traps for implements. Porcupines generally are Smithsonian Press, Washington, DC. 261 pp. ground sets. tolerated except when commercial tim- Spencer, D. A. 1948. An electric fence for use Porcupines are rather easy to livetrap ber, high-value ornamental plantings, in checking porcupine and other mammalian with large commercial cage traps (32 x orchards, or nursery plants are dam- crop depredations. J. Wildl. Manage. 10 x 12 inches [81 x 25 x 30.5 cm]) or aged by girdling, basal gnawing, or 12:110-111. homemade box traps. Place the live branch clipping. On occasion, porcu- Woods, C. A. 1978. Erethizon dorsatum. Mammal. trap in the vicinity of damage and bait pines thin dense, crowded forest Sp. 29:1-6. with a salt-soaked cloth, sponge, or stands. Often tree diameter growth is piece of wood. Live traps also can be reduced. Their preference for mistletoe set at den entrances. Move the porcu- as a food is an asset. pine 25 miles (40 km) or more to Editors The porcupine is acclaimed as a beau- Scott E. Hygnstrom ensure that it does not return. Since tiful creature of nature. It is an interest- Robert M. Timm most areas of suitable habitat carry ing animal that has an important place Gary E. Larson large porcupine populations, reloca- in the environment. It is edible and has tion of the porcupine often is neither been used by humans as an emergency helpful nor humane since the intro- food. The quills are used for decora- duced animal may have a poor chance tions, especially by Native Americans. of survival. The hair, currently used for fly-fishing Shooting lures, commands many dollars per ounce. Porcupines are not wary and Persistent hunting and shooting of can be readily observed and photo- porcupines can be effective in reducing graphed by nature lovers.