Other Mammals Table of Contents

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D-1 Armadillos Donald W. Hawthorne D-5 Bats Arthur M. Greenhall and Stephen C. Frantz D-25 Deer Scott R. Craven and Scott E. Hygnstrom D-41 Elk David S. deCalesta and Gary W. Witmer D-51 Moles F. Robert Henderson D-59 Opossums Jeffrey J. Jackson D-65 Pigs, Wild Reginald H. Barrett D-71 Pronghorn Antelope Sanford D. Schemnitz D-75 Rabbits, Cottontail Scott R. Craven D-81 Jackrabbits James E. Knight D-87 Shrews Robert H. Schmidt Donald W. Hawthorne Associate Deputy Administrator USDA-APHIS- ARMADILLOS Animal Damage Control Washington, DC 20090-6464

Fig. 1. Armadillo, Dasypus novemcinctus

Identification Damage Prevention and Fumigants The armadillo (Dasypus novemcinctus) is Control Methods None are registered. a rather interesting and unusual animal Exclusion Trapping that has a protective armor of “horny” material on its head, body, and tail. Fences or barriers are generally not Live traps (box traps). This bony armor has nine movable practical, but a possible option. Leghold traps (size No. 1 or 2). rings between the shoulder and hip Cultural Methods shield. The head is small with a long, Conibear® 220. narrow, piglike snout. Canine and inci- Clear brush and other cover to reduce Shooting sor teeth are absent. The peglike cheek habitat. One of the most commonly used teeth range in number from seven to Repellents methods. nine on each side of the upper and lower jaw. The long tapering tail is en- None are registered. Other Methods cased in 12 bony rings. The track usu- Toxicants Soil insecticides that remove food ally appears to be three-toed and shows sharp claw marks. The arma- None are registered. sources will discourage armadillos from feeding in an area. dillo is about the size of an opossum, weighing from 8 to 17 pounds (3.5 to 8 kg).

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 D-1 Great Plains Agricultural Council Wildlife Committee Range General Biology, There is evidence that armadillos may Reproduction, and be responsible for the loss of domestic The armadillo ranges from south Texas poultry eggs. This loss can be pre- to the southeastern tip of New Mexico, Behavior vented through proper housing or through Oklahoma, the southeastern fencing of nesting birds. corner of Kansas and the southwestern The armadillo is active primarily from corner of Missouri, most of Arkansas, twilight through early morning hours Disease is a factor associated with this and southwestern Mississippi. The in the summer. In winter it may be species. Armadillos can be infected by range also includes southern Alabama, active only during the day. The arma- the bacterium Mycobacterium leprae, the Georgia, and most of Florida (Fig. 2). dillo usually digs a burrow 7 or 8 causative agent of leprosy. The role inches (18 or 20 cm) in diameter and up that armadillos have in human infec- to 15 feet (4.5 m) in length for shelter tion, however, has not yet been deter- and raising young. Burrows are located mined. They may pose a potential risk in rock piles, around stumps, brush for humans, particularly in the Gulf piles, or terraces around brush or dense Coast region. woodlands. Armadillos often have several dens in an area to use for escape. Legal Status The young are born in a nest within the Armadillos are unprotected in most burrow. The female produces only one states. litter each year in March or April after a 150-day gestation period. The litter always consists of quadruplets of the Damage Prevention and same sex. The young are identical since Control Methods they are derived from a single egg. Exclusion The armadillo has poor eyesight, but a keen sense of smell. In spite of its cum- Armadillos have the ability to climb Fig. 2. Range of the armadillo in North bersome appearance, the agile arma- and burrow. Fencing or barriers, how- America. dillo can run well when in danger. It is ever, may exclude armadillos under Habitat a good swimmer and is also able to certain conditions. A fence slanted out- walk across the bottom of small ward at a 40o angle, with a portion bur- The armadillo prefers dense, shady streams. ied, can be effective. The cost of cover such as brush, woodlands, for- exclusion should be compared to other ests, and areas adjacent to creeks and Damage and Damage forms of control and the value of the re- rivers. Soil texture is also a factor in the Identification sources being protected. animal’s habitat selection. It prefers Cultural Methods sandy or loam soils that are loose and Most armadillo damage occurs as a porous. The armadillo will also inhabit Armadillos prefer to have their bur- result of their rooting in lawns, golf areas having cracks, crevices, and rocks rows in areas that have cover, so the re- courses, vegetable gardens, and flower that are suitable for burrows. moval of brush or other such cover will beds. Characteristic signs of armadillo discourage them from becoming estab- activity are shallow holes, 1 to 3 inches lished. Food Habits (2.5 to 7.6 cm) deep and 3 to 5 inches (7.6 to 12.7 cm) wide, which are dug in Repellents More than 90% of the armadillo’s diet search of food. They also uproot flow- is made up of insects and their larvae. None are currently registered or ers and other ornamental plants. Some Armadillos also feed on earthworms, known to be effective. damage has been caused by their bur- scorpions, spiders, and other inverte- rowing under foundations, driveways, Toxicants brates. There is evidence that the spe- and other structures. Some people cies will eat some fruit and vegetable None are currently registered. complain that armadillos keep them matter such as berries and tender roots awake at night by rubbing their shells Fumigants in leaf mold, as well as maggots and against their houses or other structures. pupae in carrion. Vertebrates are eaten None are currently registered; how- to a lesser extent, including skinks, liz- ever, there are some that are effective. ards, small frogs, and snakes, as well as Since state pesticide registrations vary, the eggs of these animals. check with your local extension office

D-2 or state wildlife agency for information on pesticides that are legal in your area. Trapping Armadillos can be captured in 10 x 12 x 32-inch (25 x 30.5 x 81-cm) live or box traps, such as Havahart, Tomahawk, or homemade types. The best locations to set traps are along pathways to armadillo burrows and along fences or other barriers where the animals may travel. The best trap is the type that can be opened at both ends. Its effectiveness can be enhanced by using “wings” of 1 x 4-inch (2.5 x 10-cm) or 1 x 6-inch (2.5 x 15-cm) boards about 6 feet (1.8 m) long to funnel the target animal into the trap (Fig. 3). This set does not need Fig. 3. Cage traps for armadillos are more effec- baiting. If bait is desired, use overripe tive when “wings” are added to direct the armadillo into the trap. or spoiled fruit. Other suggested baits are fetid meats or mealworms. Other traps that may be used are leghold (No. 1 or 2) or size 220 Conibear® traps. These types should Other Methods For Additional be placed at the entrance of a burrow to Since most of the damage armadillos Information improve selectivity. Care should be cause is a result of their rooting for in- taken when placing leghold traps to sects and other invertebrates in the soil, Burt, W. H., and R. P. Grossenheider. 1976. A avoid areas used by nontarget animals. soil insecticides may be used to remove field guide to the mammals, 3d ed. Houghton Mifflin Co., Boston. 289 pp. Shooting this food source and make areas less attractive to armadillos. Chamberlain, P. A. 1980. Armadillos: problems Shooting is an effective and selective and control. Proc. Vertebr. Pest Conf. 9:163- method. The best time to shoot is dur- Economics of Damage 169. ing twilight hours or at night by spot- Galbreath, G. J. 1982. Armadillo. Pages 71-79 in light when armadillos are active. A and Control J. A. Chapman and G. A. Feldhamer, eds. Wild mammals of North America: biology, shotgun (No. 4 to BB-size shot) or rifle There are few studies available on the (.22 or other small caliber) can be used. management and economics. The Johns damage caused by armadillos. The Hopkins Univ. Press, Baltimore. Good judgment must be used in deter- damage they do is localized and is usu- mining where it is safe to shoot. Check Humphrey, S. R. 1974. Zoogeography of the ally more of a nuisance than an eco- nine-banded armadillo (Dasypus local laws and ordinances before using nomic loss. novemcinctus) in the United States. BioSc. shooting as a control method. 24:457-462. Acknowledgments McBee, K., and R. J. Baker. 1982. Dasypus novemcinctus. Mammal. Sp. 162:1-9. Figure 1 from Schwartz and Schwartz (1981), adapted by Emily Oseas Routman. Figure 2 adapted from Burt and Grossenheider Editors (1976) by Jill Sack Johnson. Scott E. Hygnstrom Robert M. Timm Figure 3 by Jill Sack Johnson. Gary E. Larson

D-3 D-4 Arthur M. Greenhall Research Associate Department of Mammalogy BATS American Museum of Natural History New York, New York 10024

Stephen C. Frantz Vertebrate Vector Specialist Wadsworth Center for Laboratories and Research New York State Department of Health Albany, New York 12201-0509

Fig. 1. Little brown bat, Myotis lucifugus

Damage Prevention and Air drafts/ventilation. Removal of Occasional Bat Intruders Control Methods Ultrasonic devices: not effective. When no bite or contact has occurred, Sticky deterrents: limited efficacy. Exclusion help the bat escape (otherwise Toxicants submit it for rabies testing). Polypropylene netting checkvalves simplify getting bats out. None are registered. Conservation and Public Education Quality bat-proofing permanently Trapping Information itself functions as a management technique. excludes bats. Available, but unnecessarily Initiate control before young are born complicated compared to exclusion or after they are able to fly. and bat-proofing. Repellents Other Methods Naphthalene: limited efficacy. Sanitation and cleanup. Illumination. Artificial roosts.

Conservation and Public Education Despite their ecological value, bats are relentlessly and unjustifiably perse- cuted. Bats are often killed because they live near people who needlessly fear them. These actions emphasize the need to educate the public on the rea- sons for bat conservation and why it is important to use safe, nondestructive methods to alleviate conflicts between people and bats. General sources of information on bats include states’ Cooperative Extension Services, uni- versities, government environmental conservation and health departments, and Bat Conservation International (Austin, Texas). Except where control is necessary, bats should be appreci- ated from a distance — and not disturbed. Identification and Range

Bats, the only mammals that truly fly, belong to the order Chiroptera. Their ability to fly, their secretiveness, and their nocturnal habits have contributed Fig. 2. Little brown bat, Myotis lucifugus to bat folklore, superstition, and fear. They are worldwide in distribution and include about 900 species, second in number only to Rodentia (the rodents) among the mammals. Among the 40 species of bats found north of Mexico, only a few cause problems for humans (note that vampire bats are not found in the United States and Canada). Bats congregating in groups are called colonial bats; those that live a lone existence are known as solitary bats. The colonial species most often encountered in and around human buildings in the United States are the little brown bat, (Myotis lucifugus, Fig. 2), the big brown bat (Eptesicus fuscus, Fig. 3), the Mexican free-tailed bat (Tadarida brasiliensis, Fig. 4), the pallid bat (Antrozous pallidus), the Yuma myotis (Myotis yumanensis), and the evening bat (Nycticeius humeralis). Fig. 3. Big brown bat, Eptesicus fuscus Solitary bats typically roost in tree foliage or under bark, but occasionally are found associated with buildings, some only as transients during migration.

D-6 Fig. 4. Mexican free-tailed bat, Tadarida brasiliensis

These include Keen’s bat (Myotis keenii), the red bat (Lasiurus borealis), the silver-haired bat (Lasionycteris noctivagans), and the hoary bat (Lasiurus cinereus). Excellent illustra- tions of all bats discussed herein can be found in Barbour and Davis (1979), Wrist Knee Tuttle (1988), Geluso et al. (1987), and Ear Harvey (1986). Tail membrane Several species of bats have been included here, with significant inter- specific differences that need to be clarified if well-planned, comprehen- Tragus sive management strategies are to be Upper arm developed. Any problems caused by Calcar bats are limited to species distribution; Forearm Foot thus animal damage control personnel Thumb need not be concerned with every spe- Wing membrane cies. Colonial and solitary bats have obvious differences that serve to separate Fifth finger Second finger the species into groups (refer to Fig. 5). Fourth finger Much of the descriptive material that Third follows is adapted from Barbour and finger Davis (1979).

Fig. 5. Anatomy of a typical bat

D-7 Colonial Bats ant of high temperatures; M. keenii E. fuscus frequently shares roosts may also share the same site. Sepa- with M. lucifugus in the East, and Little brown bat (Myotis lucifugus) rate groups of males tend to be with M. yumanensis, Taderida, and Recognition smaller and choose cooler roosts Antrozous in the West. Males typi- within attics, behind shutters, under cally roost in smaller groups or forearm — 1.34 to 1.61 inches (3.4 to tree bark, in rock crevices, and alone during the summer. 4.1 cm) within caves. wingspan — 9.02 to 10.59 inches (22.9 The big brown bat is one of the most to 26.9 cm) In the winter, little brown bats in the widely distributed of bats in the ears — 0.55 to 0.63 inches (1.4 to 1.6 eastern part of their range abandon United States and is probably famil- cm) buildings to hibernate in caves and iar to more people than any other foot — approximately 0.39 inches (1.0 mines. Such hibernacula may be species. This is partially due to its cm); long hairs on toes extend be- near summer roosts or up to a few large, easy-to-observe size, but also yond claws. hundred miles (km) away. Little is to its ability to overwinter in build- known of the winter habits of M. ings (attics, wall spaces, and base- Distribution (Fig. 6a) lucifugus in the western United ments). Its close proximity to Color States. humans, coupled with its tendency to move about when temperature The life span of little brown bats has Pale tan through reddish brown to shifts occur, often brings this bat been established to be as great as 31 dark brown, depending on geo- into human living quarters and years. The average life expectancy, graphic location. The species is a basements in summer and winter. however, is probably limited to only rich dark brown in the eastern Big browns also hibernate in caves, a few years. United States and most of the west mines, storm sewers, burial vaults, coast. Fur is glossy and sleek. Big brown bat (Eptesicus fuscus) and other underground harborage. Confusion may occur with a few other While E. fuscus will apparently “house” bat species. In the East, it Recognition travel as far as 150 miles (241 km) to hibernacula, the winter quarters of may be confused with Keen’s bat forearm — 1.65 to 2.01 inches (4.2 to the bulk of this species are largely (M. keenii), which has longer ears 5.1 cm) unknown. [0.69 to 0.75 inches (1.7 to 1.9 cm)] wingspan — 12.80 to 13.78 inches (32.5 and a longer, more pointed tragus to 35.0 cm) Big brown bats may live as long as 18 (the appendage at the base of the ears — with rounded tragus years. ear). In the West, it resembles the Distribution (Fig. 6b) Yuma myotis (M. yumanensis), Mexican free-tailed bat (Tadarida which has dull fur and is usually Color brasiliensis) smaller. However, the Yuma myotis and little brown may be indistin- From reddish brown, copper colored, Recognition to a dark brown depending on geo- guishable in some parts of the forearm — 1.42 to 1.81 inches (3.6 to graphic location. This is a large bat northwestern United States where 4.6 cm) without distinctive markings. they may hybridize. wingspan — 11.42 to 12.80 inches (29.0 Habits Confusion may occur with the evening to 32.5 cm); long narrow wings bat (Nycticeius humeralis) though the tail (interfemoral) membrane — does This is one of the most common bats latter is much smaller. not enclose the lower one-third to found in and near buildings, often one-half of the tail, hence the name Habits located near a body of water where free-tailed they forage for insect prey. Summer This hardy, rather sedentary species foot — long, stiff hairs as long as the colonies are very gregarious, com- appears to favor buildings for roost- foot protrude from the toes. monly roosting in dark, hot attics ing. Summer maternity colonies Distribution (Fig. 6c) and associated roof spaces where may include a dozen or so and up maternity colonies may include to a few hundred individuals, roost- Color hundreds to a few thousand indi- ing behind chimneys, in enclosed Dark brown or dark gray. Fur of some viduals. Colonies may also form eaves, in hollow walls, attics, barns, individuals may have been beneath shingles and siding, in tree and behind shutters and unused bleached to a pale brown due to hollows, beneath bridges, and in sliding doors. They also form colo- ammonia fumes from urine and de- caves. Litter size is 1 in the North- nies in rock crevices, beneath composing guano. east; twins occasionally occur in bridges, in hollow trees, and under some other areas. The roost is often loose bark. Litter size is 2 in the East Confusion is not likely to occur with shared with the big brown bat (E. to the Great Plains; from the other species that commonly inhabit fuscus) though the latter is less toler- Rockies westward 1 young is born. human buildings.

D-8 Habits Habits M. yumanensis is more closely associated with water than is any other T. brasiliensis forms the largest colonies Maternity colony size ranges from North American bat species. Nearly of any warm-blooded animal, estab- about 12 to 100 individuals. Roost all roosts have open water nearby. lishing sizable colonies in buildings, sites include buildings, bridges, and This species is not as tolerant as M. particularly on the West Coast and rock crevices; less frequently, tree lucifugus of high roost temperatures in the Gulf states from Texas east. cavities, caves, and mines. Litter and will move to cooler niches Hundreds to thousands may be size is most commonly 2. The roost within a building when tempera- found in buildings or under is frequently shared with T. tures rise much above 100o F bridges. It is primarily a cave bat in brasiliensis and E. fuscus in the West. (37.8o C). Arizona, New Mexico, Oklahoma, While groups of males tend to seg- and Texas; buildings are used as regate during the nursery period M. yumanensis abandons maternity temporary roosts during migra- (sometimes in the same building), colonies in the fall, but its winter tions. Litter size is 1. other males are found within the habitat is not known. maternity colony. Taderida often share roosts with other Evening bat (Nycticeius humeralis) species. In the West, for example, An interesting feature of pallid bats is they may be found in buildings that they fly close to the ground, Recognition with A. pallidus, M. yumanensis, and may hover, and take most prey on forearm — 1.30 to 1.54 inches (3.3 to E. fuscus. Some males are always the ground, not in flight. Prey 3.9 cm) present in the large maternity colo- includes crickets, grasshoppers, wingspan — 10.24 to 11.02 inches (26.0 nies, but they tend to segregate in beetles, and scorpions. They will to 28.0 cm) separate caves. also forage among tree foliage. ears — with short, curved, and A few Taderida may overwinter in Pallid bats are not known to make long rounded tragus buildings as far north as South migrations, though little is known Confusion may occur with the big Carolina in the East and Oregon in of their winter habits. brown bat (E. fuscus), which can be the West. Most of this species readily distinguished by its larger migrate hundreds of miles to Yuma myotis (Myotis yumanensis) size. It bears some resemblance to warmer climes (largely to Mexico) Recognition the somewhat smaller little brown for the winter. forearm — 1.26 to 1.50 inches (3.2 to bat (M. lucifugus) but can be identified by its characteristic blunt Pallid bat (Antrozous pallidus) 3.8 cm) wingspan — about 9.25 inches (23.5 tragus. Recognition cm) Distribution (Fig. 6f) forearm — 1.89 to 2.36 inches (4.8 to ears — 0.55 to 0.59 inches (1.4 to 1.5 cm) Color 6.0 cm) foot — 0.39 inches (1.0 cm) wingspan — 14.17 to 15.35 inches (36.0 Distribution (Fig. 6e) Medium brown with some variation to to 39.0 cm) yellow-brown in subtropical ears — large; widely separated and Color Florida. No distinctive markings. more than half as broad as long. Light tan to dark brown; underside is Habits The ears are nearly half as long as whitish to buffy. the combined length of the bat’s Summer maternity colonies in build- head and body. Confusion may occur in the West with ings may consist of hundreds of eyes — large M. lucifugus, though the latter tends individuals. Litter size is usually 2. to have longer, glossier fur, and is Colonies also form in tree cavities Distribution (Fig. 6d) larger. In the Northwest, hybridiza- and under loose tree bark. In the Color tion occurs with M. lucifugus, mak- Southeast, T. brasiliensis commonly ing the species indistinguishable. inhabits the same building with N. pale, upper parts are light yellow, the humeralis. This is one of the most hairs tipped with brown or gray. Habits common bats in towns throughout Underparts are pale creamy, almost Maternity colonies, up to several the southern coastal states. Very white. This large, light-colored bat thousand individuals, form in the little is known about this species, is relatively easy to recognize. summer in attics, belfries, under and virtually nothing is known of Confusion with other species that com- bridges, and in caves and mines. its winter habitat except that it monly inhabit human buildings is Litter size is 1. Males typically almost never enters caves. not likely to occur. segregate during the nursery period and roost as solitary individuals in buildings and other suitable harborage.

D-9 Solitary Bats Habits may roost in and on buildings. The litter size is 2. The sexes segregate Keen’s bat (Myotis keenii) Red bats live solitary lives, coming together only to mate and migrate. through much of the summer range. Recognition Few people are familiar with this spe- L. noctivagans hibernates in tree crevices, forearm — 1.26 to 1.54 inches (3.2 to cies. They typically spend summer under loose bark, in buildings 3.9 cm) days hidden in the foliage of decidu- (including churches, sky scrapers, and wingspan — 8.98 to 10.16 inches (22.8 ous trees. The number of young ranges wharf houses), hulls of ships, rock to 25.8 cm) from 1 to 4, averaging 2.3. crevices, silica mines, and non- ears — 0.67 to 0.75 inches (1.7 to 1.9 cm); These bats often chase insects that are limestone caves. It also may migrate, with a long, narrow, pointed tragus attracted to lights, such as street during which time it is encountered in buildings (they favor open sheds, Distribution (Fig. 6g) lamps. It is this behavior that most likely brings them in close proxim- garages, and outbuildings rather than Color ity to people. enclosed attics), in lumber piles, and on ships at sea. Brown, but not glossy; somewhat paler L. borealis is well-adapted for surviving Hoary bat (Lasiurus cinereus) in the East. drastic temperature fluctuations; it Confusion may occur with M. does not hibernate in caves, but Recognition lucifugus, which has glossy fur, apparently in trees. Some migrate shorter ears, and does not have the long distances. During migration, forearm — 1.81 to 2.28 inches (4.6 to 5.8 cm) long, pointed tragus. red bats have been known to land wingspan — 14.96 to 16.14 inches (38.0 on high-rise buildings and on Habits to 41.0 cm) ships at sea. ears — relatively short, rounded, Excluding small maternity colonies (up Silver-haired bat (Lasionycteris edged with black, and with fur to 30 individuals are on record), M. noctivagans) tail membrane — completely furred on keenii are generally found singly in the upper surface East. Roosting sites include: behind Recognition Distribution (Fig. 6j) shutters, under wooden shingles, shel- forearm — 1.46 to 1.73 inches (3.7 to tered entryways of buildings, in roof 4.4 cm) Color spaces, in barns, and beneath tree wingspan — 10.63 to 12.20 inches (27.0 Dark, but many hairs are tipped in bark. In the West, this bat is known as to 31.0 cm) white, giving it a frosted appear- a solitary species, roosting in tree cavi- ears — short, rounded, hairless ance. This bat also has a yellowish ties and cliff crevices. Litter size is tail membrane — upper surface is or orangish throat “collar.” probably 1. The roost is sometimes sparsely furred on the anterior one- shared with M. lucifugus. The sexes half. Confusion may sometimes occur with probably segregate during the nurs- the much smaller silver-haired bat Distribution (Fig. 6i) ery period. In winter, these bats hiber- (Lasionycteris noctivagans), which nate in caves and mines. Color lacks the fur patches and markings on the ears, markings on the throat, Red Bat (Lasiurus borealis) Usually black with silver-tipped fur; and has a tail membrane that is only some individuals with dark brown, Recognition lightly furred on the upper surface. yellowish-tipped fur. forearm — 1.38 to 1.77 inches (3.5 to Habits 4.5 cm) Confusion sometimes occurs with the wingspan — 11.42 to 13.07 inches (29.0 larger hoary bat (Lasiurus cinereus), Hoary bats generally spend summer to 33.2 cm); long, pointed wings which has patches of hair on the ears days concealed in tree foliage (often ears — short rounded and wings, heavy fur on the entire in evergreens), rarely enter houses, tail membrane — heavily furred on upper surface of the tail membrane, and are not commonly encountered upper surface, with a distinctive and has a distinctive throat “collar.” by people. L. cinereus at their day long tail. Habits roosts are usually solitary except Distribution (Fig. 6h) when with young. The litter size is The silver-haired bat roosts in a wide 2. The sexes segregate through most Color variety of harborages. A typical of the summer range. roost might be behind loose tree Bright orange to yellow-brown; usu- bark; other sites include tree hol- This is one of the largest bats in North ally with a distinctive white mark lows and bird nests. This species is America, a powerful flier, and an on the shoulders. solitary except when with young. accomplished migrant. Records Confusion may occur with the hoary Additionally, there are unconfirmed indicate that some L. cinereus may bat (L. cinereus), which is frosted- reports that it is sometimes colonial hibernate in northern parts of their gray in appearance and larger. (Dalquest and Walton 1970) and range.

D-10 abc

def

g hi

Figure 6. Distributions of selected bat species in North America: (a) little brown bat, (b) big brown bat, (c) Mexican free-tailed bat, (d) pallid bat, (e) Yuma myotis, (f) evening bat, (g) Keen’s bat, (h) red bat, (i) silver-haired bat, (j) hoary bat.

D-11 Food Habits migrate relatively short distances, Modification and destruction of roost whereas certain populations of the sites has also decreased bat numbers. Bats in North America are virtually all Mexican free-tailed bat may migrate Sealing and flooding of mineshafts and insectivorous, feeding on a variety of up to 1,000 miles (1,600 km). Bats in caves and general quarrying opera- flying insects (exceptions among house the northern United States and Canada tions may inadvertently ruin bat har- bats were noted previously). Many of may hibernate from September borages. Forestry practices have the insects are harmful to humans. through May. Hibernation for the reduced the number of hollow trees While there must be some limitations same species in the southern part of available. Some of the elimination of based on such factors as bats’ body their range may be shorter or even natural bat habitat may contribute to size, flight capabilities, and jaw open- sporadic. Some may fly during warm bats roosting in buildings. ing, insectivorous bats apparently con- winter spells (as big brown bats may in sume a wide range of prey (Barbour the northeastern part of the United Damage and Damage and Davis 1979). The little brown bat’s States). Bats often live more than 10 Identification diet includes mayflies, midges, mos- years. quitoes, caddis flies, moths, and In response to a variety of human Bat Presence beetles. It can consume insects equal to activities, direct and indirect, several Bats often fly about swimming pools, one-third of its body weight in 1/2 bat species in the United States have from which they drink or catch insects. hour of foraging. The big brown bat declined in number during the past White light (with an ultraviolet com- may fill its stomach in about 1 hour few decades. Chemical pesticides (par- ponent), commonly used for porch (roughly 0.1 ounce per hour [2.7 g/hr]) ticularly the use of persistent and lights, building illumination, street and with prey including beetles, moths, fly- bioaccumulating organic pesticides) parking-lot lights, may attract flying ing ants, true bugs, mayflies, caddis have decreased the insect supply, and insects, which in turn attract bats. flies, and other insects. The nightly contaminated insects ingested by bats Unfortunately, the mere presence of a consumption of insects by a colony of have reduced bat populations. Many bat outdoors is sometimes beyond the bats can be extremely large. bats die when people disturb summer tolerance of some uninformed people. maternity roosts and winter hiber- Information is a good remedy for such nacula. Vandals and other irrespon- situations. General Biology, sible individuals may deliberately kill Reproduction, and bats in caves and other roosts. Even Bats commonly enter buildings through openings associated with the Behavior the activities of speleologists or biologists may unintentionally disturb roof edge and valleys, eaves, apex of hibernating bats, which depletes fat the gable, chimney, attic or roof vent, Most North American bats emit high reserves needed for hibernation. dormers, and siding (see Fig. 7). Other frequency sounds (ultrasound) inau- dible to humans and similar to sonar, in order to avoid obstacles, locate and capture insect prey, and to communi- cate. Bats also emit audible sounds Under roofing Ridge cap Chimney flue that may be used for communication Fascia boards Under siding between them. Between house & chimney Drip edge Bats generally mate in the fall and win- Flashing ter, but the female retains the sperm in Rafters the uterus until spring, when ovulation Vent Soffits Hollow walls and fertilization take place. Pregnant Under females may congregate in maternity porch colonies in buildings, behind chim- roof neys, beneath bridges, in tree hollows, caves, mines, or other dark retreats. No nests are built. Births typically occur from May through July. Young bats grow rapidly and are able to fly within 3 weeks. Weaning occurs in July and August, after which the nursery colonies disperse. Bats prepare for winter around the time of the first frost. Some species Fig. 7. Common points of entry and roosting sites of house bats.

D-12 openings may be found under loose- semi-enclosed (loading docks, entrance be segmented, elongated, and friable. fitting doors, around windows, gaps foyers), partially sheltered (porches, When crushed, they become powdery around various conduits (wiring, carports, pavilions, highway under- and reveal shiny bits of undigested plumbing, air conditioning) that pass passes, bridges), and open structural insect remains. In contrast, mice and through walls, and through utility areas (window shutters, signs). Once rat droppings tend to taper, are vents. there, active bats in and on buildings unsegmented, are harder and more can have several economic and aes- fibrous, and do not become powdery Bats are able to squeeze through nar- thetic effects, often intertwined with when crushed (unless extremely aged). row slits and cracks. For purposes of public health issues (Frantz, 1988). bat management, one should pay The droppings of some birds and liz- Unusual roosting areas include wells, attention to any gap of approximately ards may occasionally be found along sewers, and graveyard crypts. Before 1/4 x 1 1/2 inches (0.6 x 3.8 cm) or a with those of bats. However, bat drop- considering control measures, verify hole 5/8 x 7/8 inch (1.6 x 2.2 cm). Such pings never contain the white chalky that bats are actually the cause of the openings must be considered potential material characteristic of the feces of problem. entries for at least the smaller species, these other animals. such as the little brown bat. The Rub Marks Bat excrement produces an unpleasant smaller species require an opening no odor as it decomposes in attics, wall Surface areas on walls, under loose wider than 3/8 inch (0.95 cm), that is, a spaces, and other voids. The pungent, woodwork, between bricks and hole the diameter of a US 10-cent coin musty, acrid odor can often be around other bat entryways often have (Greenhall 1982). Openings of these detected from outside a building con- a smooth, polished appearance. The dimensions are not uncommon in taining a large or long-term colony. stained area is slightly sticky, may con- older wood frame structures where Similar odor problems occur when ani- tain a few bat hairs, and is yellow- boards have shrunk, warped, or other- mals die in inaccessible locations. The brown to blackish brown in color. The wise become loosened. odor also attracts arthropods which smooth gloss of these rub marks is due may later invade other areas of a The discovery of one or two bats in a to oils from fur and other bodily secre- building. house is a frequent problem. In the tions mixed with dust, deposited there Northeast, big brown bats probably as many animals pass repeatedly for a Bat guano may provide a growth account for most sudden appearances long period over the same surface. medium for microorganisms, some of (see Figs. 3 and 8). Common in urban Openings marked in this way have which are pathogenic (histoplasmosis, areas, they often enter homes through been used heavily by bats. for example) to humans. Guano accu- open windows or unscreened fire- mulations may fill spaces between places. If unused chimneys are selected Noise walls, floors, and ceilings. It may cre- for summer roosts, bats may fall or ate a safety hazard on floors, steps, Disturbing sounds may be heard from crawl through the open damper into and ladders, and may even collapse vocalizations and grooming, scratch- the house. Sometimes bats may appear ceilings. Accumulations also result in ing, crawling, or climbing in attics, in a room, then disappear by crawling the staining of ceilings, soffits, and sid- under eaves, behind walls, and under a door to another room, hall- ing, producing unsightly and between floors. Bats become particu- way, or closet. They may also disap- unsanitary conditions. pear behind curtains, wall hangings, larly noisy on hot days in attics, before bookcases, under beds, into waste bas- leaving the roost at dusk, and upon Bats also urinate and defecate in flight, kets, and so forth. Locating and returning at dawn. Note that rustling causing multiple spotting and staining removing individual bats from living sounds in chimneys may be caused by on sides of buildings, windows, patio quarters can be laborious but is birds or raccoons and scratching and furniture, automobiles, and other important. If all else fails, wait until thumping sounds in attics and behind objects at and near entry/exit holes or dusk when the bat may appear once walls may indicate rats, mice, or beneath roosts. Bat excrement may again as it attempts to find an exit. squirrels. also contaminate stored food, commer- Since big brown bats may hibernate in cial products, and work surfaces. Guano and Urine the cooler recesses of heated buildings, Bat urine readily crystallizes at room they may suddenly appear (flying Fecal pellets indicate the presence of temperature. In warm conditions un- indoors or outdoors) in midwinter animals and are found on attic floors, der roofs exposed to sun and on chim- during a warm spell or a cold snap as in wall recesses, and outside the house ney walls, the urine evaporates so they move about to adjust to the tem- at its base. Fecal pellets along and quickly that it crystallizes in great perature shift. inside walls may indicate the presence accumulations. Boards and beams of mice, rats, or even roaches. Since saturated with urine acquire a whitish Roosting Sites most house bats north of Mexico are powderlike coating. With large num- Bats use roosting niches that are insectivorous, their droppings are bers of bats, thick and hard stalactites indoors (human dwellings, outbuild- easily distinguished from those of and stalagmites of crystallized bat ings, livestock quarters, warehouses), small rodents. Bat droppings tend to urine are occasionally formed.

D-13 Although the fresh urine of a single bat priate surfaces (affected attic beams, result of accidental or careless han- is relatively odorless, that of any mod- soffits) with boric acid powder or dia- dling of grounded bats. Even less fre- erate-sized colony is obvious, and the tomaceous earth; carefully read all quently, bats in this stage of illness odor increases during damp weather. product labels before using any pesti- may be involved in unprovoked Over a long period of time urine may cide. Note that neither rabies nor attacks on people or pets (Brass, pers. cause mild wood deterioration (Frantz Lyme disease is transmitted by any commun.; Trimarchi et al. 1979). It is and Trimarchi 1984). As the urine satu- arthropods associated with bats. during this stage that the rabid bat is rates the surfaces of dry wood beams capable of transmitting the disease by and crystallizes, the wood fibers Public Health Issues biting another mammal. As the disease expand and separate. These fibers then Rabies—General Epidemiology. progresses the bat becomes increas- are torn loose by the bats crawling Bats are distinct from most vertebrate ingly paralyzed and dies as a result of over such surfaces, resulting in wood pests that inhabit human dwellings be- the infection. The virus in the carcass is fibers being mixed with guano accu- cause of the potential for transmitting reported to remain infectious until mulations underneath. rabies — a viral infection of mammals decomposition is well advanced. The close proximity of bat roosts to that is usually transmitted via the bite Significance. Rabies is the most human living quarters can result in of an infected animal. Rabies does not important public health hazard associ- excreta, animal dander, fragments of respond to antibiotic therapy and is ated with bats. Infection with rabies arthropods, and various microorgan- nearly always fatal once symptoms has been confirmed in all 40 North isms entering air ducts as well as fall- occur. However, because of the long American species of bats that have ing onto the unfortunate residents incubation period (from 2 weeks to been adequately sampled in all of the below. Such contaminants can result in many months), prompt vaccination contiguous United States and in most airborne particles of public health sig- following exposure can prevent the provinces of Canada. Figure 8 shows nificance (Frantz 1988). disease in humans. Dogs, cats, and the frequency of bat species submitted livestock also can be protected by for rabies testing in New York State Ectoparasites and other periodic vaccinations. over the last 12 years. While not a Arthropods Bats are not asymptomatic carriers of nationwide measure of human Several arthropods (fungivores, detri- rabies. After an incubation period of 2 encounters with bats, Figure 8 illus- tivores, predators, and bat ectopara- weeks to 6 months, they become ill trates that bat species are not encoun- sites) are often associated with colonies with the disease for as long as 10 days. tered equally. Note that bats submitted of bats in buildings. Their diversity de- During this latter period, a rabid bat’s for testing are often ill and/or easily pends on the number of bats, age and behavior is generally not normal—it captured. The numbers and species quantity of excreta deposits, and sea- may be found active during the day- encountered will vary with the region son. Arthropods such as dermestid time or on the ground incapable of fly- of the country; data are generally beetles (Attagenus megatoma) contribute ing. Most human exposures are the available from local and state health to the decomposition of guano and in- authorities. sect remnants, but may also become a pest of stored goods and/or a nuisance within the living quarters. Cock- roaches (for example, Blatta orientalis) Big Brown (R = 6.0%) attracted to guano may invade other parts of a building. Bat bugs (Cimex Little Brown (R = 1.0%) spp.) are sometimes found crawling on the surface of beams or around holes Keen’s (R = 1.8%) leading to secluded recesses used by bats. Bat ectoparasites (ticks, mites, Red (R = 5.7%) fleas, and bugs) rarely attack humans or pets and quickly die in the absence Hoary (R = 16.3%) of bats. Ectoparasites may become a nuisance, however, following exclu- Silver-haired (R = 8.9%) sion of large numbers of bats from a well-established roost site. Area fumi- Other and Unknown (R = 2.5%) gation with a total release pyrethrum- based aerosol may be an appropriate solution for arthropod knockdown 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 within an enclosed space, but only af- Number of Bats ter bats have departed. For long-term arthropod control, lightly dust appro- Fig. 8. Profile of bat species submitted to the New York State Rabies Laboratory, 1981-1992.

D-14 Random sampling of bats (healthy and Numerous wild and domestic animals lesions on routine radiographs. Other ill) indicates an overall infection rate of are susceptible to histoplasmosis, but individuals may have chronic or pro- less than 1%. Finding a rabid bat in a bats (and perhaps the armadillo) are gressive lung disease requiring treat- colony does not imply that the remain- the only important animal vectors. ment. Less severe forms of these ing animals are rabid. In fact, the prob- Unlike bats, birds do not appear to infections may be accompanied by ability of immediately finding more become infected with the fungus. Both fever, cough, and generalized symp- than one additional infected bat in that the presence of guano and particular toms similar to a prolonged influenza. colony is small. environmental conditions are neces- Resolution of the disease confers a sary for H. capsulatum to proliferate. In degree of immunity to reinfection. In Bats rank third (behind raccoons and avian habitats, the organism appar- addition, resolution confers varying skunks) in incidence of wildlife rabies ently grows best where the guano is in degrees of hypersensitivity to H. in the United States (Krebs et al. 1992). large deposits, rotting and mixed with capsulatum; as a consequence, massive In the last 20 years, however, there soil rather than in nests or in fresh reinfection in highly sensitized lungs have been more human rabies cases of deposits. Specific requirements regard- may result in a fatal acute allergic bat origin in the United States than of ing bats have not been described, reaction. any other wildlife group. Furthermore, though bat roosts with long-term the disease in bats is more widely dis- In a small percentage of chronic infestation are often mentioned in the tributed (in all 48 contiguous states in histoplasmosis cases, the fungus dis- literature. 1989) than in any other species. In seminates to involve multiple organ Canada, bats also rank third (behind While histoplasmosis in the United systems and may be fatal. This form is foxes and skunks) in the incidence of States is particularly endemic to the usually seen in young children (1 year wildlife rabies. Therefore, every bat Ohio-Mississippi Valley region (which or older) and in immunocompromised bite or contact must be considered a is also an area with the greatest star- adults. In recent years, systemic infec- potential exposure to rabies. While ling concentration) and areas along the tions have been increasing in fre- aerosol transmission of the rabies virus Appalachian Mountains, it is also quency globally as an opportunistic from bats in caves to humans and found in the lake and river valleys of infection of AIDS patients. some other mammals has been other states. Outside areas with reported, this is not a likely route of “appropriate” environmental condi- Legal Status infection for humans entering bat tions, there also occur scattered foci roosts in buildings in temperate North with high infection rates usually The lethal control of bats, even when America. Note that vampire bats are associated with caves inhabited by there is a proven potential danger to not a threat north of Mexico. bats or birds. humans, often is subjected to careful scrutiny and interagency coordination. Significance. When soil or guano Histoplasmosis—General Epidemi- A survey of federal legislative actions, containing H. capsulatum is physically ology. Histoplasmosis is a very com- court decisions, and agency interpreta- disturbed, the spores become airborne. mon lung disease of worldwide tions concerning bats can be found in Persons at particular risk of histoplas- distribution caused by a microscopic Bat Management in the United States mosis of bat origin include spelunkers, fungus, Histoplasma capsulatum. (Lera and Fortune 1979). bat biologists, pest control technicians, Histoplasma exists in nature as a sapro- people who clean out or work in areas phytic mold that grows in soil with Some states have laws that specifically where bats have habitually roosted, high nitrogen content, generally associ- mention bats, either providing or and people in contact with guano- ated with the guano and debris of denying protection. Others have legis- enriched soil — such as around the birds (particularly starlings, Sturnus lation that applies to bats only by foundation of a building where guano vulgaris, and chickens) and bats. Wind interpretation, since bats may be con- has sifted down through the walls. is probably the main agent of dis- sidered nongame wildlife or indig- enous state mammals. Some bats have persal, but the fungus can survive and Infection occurs upon inhalation of protection as either federal or state- be transmitted from one site to another spores and can result in a variety of listed endangered species, but the in the intestinal contents of bats, and clinical manifestations; severity par- same state may not protect other spe- also in the dermal appendages of both tially depends on the quantity of cies of bats. Enforcement and public bats and birds. The disease can be spores inhaled. The infection may education must accompany legislation acquired by the casual inhalation of remain localized in the lungs where it to accomplish the intended goal of windblown spores, but infections are may resolve uneventfully; this is the protecting the public and saving more likely to result from visits to case for about 95% of the 500,000 infec- endangered bats. Familiarity with the point sources of growth of the fungus. tions occurring annually in the United appropriate federal and state laws Relative to bats, such sources include States. Such infections are identified should precede any nuisance manage- bat roosts in caves, barns, attics, and only by the presence of a positive ment activities. belfries, and soil enriched with bat histoplasmin skin test and/or calcified guano.

D-15 Damage Prevention and Locating the Roost(s). It is not America. Treatments might otherwise Control Methods always possible or convenient to con- result in the unnecessary death of ani- duct a bat watch. Thus, a detailed in- mals (especially young unable to fly) spection inside the building for bats or trapped inside, offensive odors, and Premanagement Considerations bat sign may be necessary to find attraction of arthropod scavengers. Bat Watch for Infestation Confir- specific roosts. Daytime is best, espe- Disease Considerations mation. To confirm that bats are actu- cially during the warmer part of the ally roosting in or on a building, look day. Bats roost in the most varied Rabies — Preventive Measures. It for bats flying in and out of a site and/ kinds of buildings and in every part should be noted that newspapers, tele- or for signs of infestation. A bat watch from cellar to attic. Some types of vision, and other mass media some- can be conducted by two people (more buildings appear preferable (older times misrepresent the role of rabid may be necessary to observe large or houses, churches, barns, proximity to bats as a risk to humans. However, the complex sites) posted at opposite cor- water) as do certain roost locations unfortunate recent (1983 to 1993) ners of a structure. An evening watch therein, especially areas with little dis- deaths of a 22-year-old man in Texas, a begins about 30 minutes before dark turbance, low illumination, little air cir- 30-year-old bat scientist in Finland, a and a morning watch begins about 1 culation, and high temperatures. Often university student in British Columbia, hour before dawn. Observations it is easy to locate bats, especially in a 5-year-old girl in Michigan, a man in should continue for approximately 1 warm weather in attics or lofts, where Arkansas, an 11-year-old girl in New hour. they may hang in clusters or side-by- York, and a woman in Georgia amply side from the sloping roof lath, beams, underscore the need to pay prompt Such observations can indicate exit/ and so forth. However, bats have the attention to bat bites and other entry points and the number of bats. ability to find crevices and cavities, exposures. With practice, distinguishing some bat and if disturbed may rapidly disap- species may also be possible. For Many rabies exposures could be pear into the angles between converg- example, compared to the big brown avoided if people simply refrained ing beams, behind such beams or bat, the little brown bat is noticeably from handling bats. Adults and chil- wallboards, into mortise holes on the smaller in size, and its flight has more dren should be strongly cautioned underside of beams, and into the mul- rapid wing beats, and more rapid never to touch bats with bare hands. tilayered wall and roof fabrications. If turning and darting. All necessary measures should be bats cannot be openly observed, usu- taken to ensure that bats cannot enter It may be necessary to watch for more ally there are various interior and exte- living quarters in houses and apart- than one night to compensate for rior signs of their presence. Often there ments. Pet cats and dogs should be weather conditions, bats’ sensitivity to are multiple roost sites within or on a kept up-to-date in rabies vaccinations. observers, noisy or inexperienced ob- single building. This is also true for pets confined servers, and improper use of light. Ob- Problem Assessment. Once it has indoors, because contact with bats fre- servations can be enhanced with a been confirmed that bats are present, quently occurs indoors. Valuable live- standard flashlight, but be certain to one must determine if there is damage, stock also should be vaccinated if kept keep the bright part of the beam as far if there is a health risk, and if some in buildings harboring bats or if in a as possible away from the exit hole be- intervention is warranted. There are rabies outbreak area (NASPHV 1993). ing observed. Bright light will increase circumstances in which “no action” is While transmission of rabies from bats bats’ reluctance to exit and may result the correct action because of the bene- to terrestrial mammals apparently is in an incomplete exit of the colony. A ficial role of bats. In cases where there not common, such incidents have been valuable observation aid is a powerful, is risk of contact, damage from excreta reported (Reid-Sanden et al. 1990, rechargeable flashlight equipped with accumulations, stains, and so on, inter- Trimarchi 1987). Dogs, cats, and live- a plastic, red pop-off filter (similar to vention may be necessary. stock that have been exposed to a the Kodak Wratten 89B). Also, an elec- rabid or suspected-rabid animal, but tric headlamp, supplied with recharge- Timing. With the exception of disease are not currently vaccinated, must be able batteries and fitted to a climbing treatment and removal of the occa- either quarantined or destroyed. or spelunking helmet, allows hands-off sional bat intruder, timing becomes an illumination outdoors as well as in- important planning consideration. Lastly, pest control technicians, nui- doors when exploring roost locations. Management procedures must not sance wildlife control personnel, wild- Bats are sensitive to light intensity and complicate an already existing prob- life biologists, and other individuals at can visually discriminate shapes and lem and should emphasize bat conser- particular risk of contact with rabid patterns in extremely low light situa- vation. Therefore, all interventions bats (or other wildlife) should receive a tions. They can only see in black and should be initiated before the young rabies pre-exposure vaccination. This white; hence, the low-contrast illumi- are born or after they are weaned and effective prophylaxis involves only nation and soft shadows produced by able to fly. Thus, the annual opportu- three injections of rabies vaccine, red light has little effect on bats. nity extends from about mid-August which are administered in the arm to mid-May for much of North during a month’s time.

D-16 Rabies — Treatment for Expo- nated, wear protective clothing and Removal of Occasional Bat sure. If a person is bitten or scratched gloves that can be removed at the site Intruders by a bat, or there is any suspicion that and placed in a plastic bag for later de- A bat that has blundered into the liv- bat saliva or nervous tissue has con- contamination via formalin and washing quarters of a house will usually taminated an open wound or mucous ing. Also, clean footwear before find its way out by detecting air move- membrane, wash the affected area leaving the site to prevent spore dis- ment. When no bite or contact with thoroughly with soap and water, cap- semination in cars, the office, at home, people or pets has occurred, the sim- ture the bat without damaging the and elsewhere. plest solution for “removing” the bat is head, and seek immediate medical Guano deposits and guano-enriched to try to confine it to one room, then attention. The incident should be soils should not be unnecessarily dis- open windows and doors leading out- reported promptly to local health turbed. Dampening with water or doors and allow it to escape. If the bat authorities in order to arrange rabies scheduling outdoor work at a time is present at night, the lights should be testing of the bat. when the ground is relatively wet will dimmed to allow the animal to find If the bat is captured and immediate minimize airborne dust. Chemically open doors and windows; some light transportation to the testing laboratory decontaminate known infective foci is necessary if an observer is to insure is possible, and if immediate testing with a spray of 3% formalin (see CDC that the bat finds its way out. If bright can be arranged, postexposure treat- 1977). To protect the environment, lights are kept on, the bat may become ment may be delayed several hours decontamination must be conducted confused and may seek refuge behind until the test results are known. in accordance with state and local shelving, curtains, hanging pictures, or Postexposure prophylaxis must be regulations. Chemical decontamina- under furniture. administered immediately, however, if tion of an “active” bat roost should be Healthy bats normally will not attack the bat cannot be captured, if prompt conducted only after the bats have people even when chased. Chasing a transportation to the laboratory is not been excluded or after bats have flying bat with a folded newspaper, possible, if the specimen is not suitable departed for hibernation. tennis racket, or stick will cause the bat for reliable diagnosis, or if the test Histoplasmosis — Treatment. to take evasive action, and a bat’s results prove positive for rabies. Most infections in normally healthy flight reversal to avoid a wall is often The prophylaxis has little resemblance individuals are benign and self-limit- misinterpreted as an attack. These to that of many years ago. Today, it ing and do not require specific therapy flailings, often futile, will cause a bat to consists of one dose of rabies immune (George and Penn 1986; Rippon 1988). seek safety wherever possible, making globulin (human origin) and one dose Treatment with an antifungal agent escape more difficult for the bat and of rabies vaccine (human diploid cell) may be prescribed in more severe more frustrating for the human. administered preferably on the day of cases; amphotericin B and/or oral If the bat has difficulty escaping, it can exposure, followed by additional imidazole ketoconazole are typically be captured in a hand net (for exam- single doses of rabies vaccine on days recommended depending on the spe- ple, an insect net [Fig. 9]). Otherwise, 3, 7, 14, and 28 following the initial cific nature of the infection. injection. This treatment is normally safe, relatively painless, and very effective. Histoplasmosis — Preventive Measures. Histoplasmosis can most easily be prevented by avoiding areas that harbor H. capsulatum. Since this is not practical for individuals who must work in and around active/inactive bat roosting sites, other measures can be recommended to reduce the risk of infection during cleaning, field study, demolition, construction, and other activities. Persons working in areas known or suspected to be contaminated with H. capsulatum should always wear protective masks capable of filtering out particles as small as 2 microns in diameter or use a self-contained breathing appa- ratus. In areas known to be contami- Fig. 9. Using an insect net to remove a bat from a building.

D-17 wait for it to come to rest, quickly sue or plastic will wave and flutter cover it with a coffee can or similar from air movements (Fig. 10). Indoor container, and slide a piece of card- air leaks can be found easily by the use board or magazine under the can to of an air flow indicator (Fig. 11). Small- trap the bat inside (NYSDH 1990). volume smoke generators can be used Take the captured bat outdoors and to locate openings in the floor, ceiling, release it away from populated areas, attic, and basement. Obscure openings preferably after dark. Note that also may be located from outside the reasonably thick work gloves should house by activating smoke candles or be worn at all times when trying to smoke bombs (as within an attic), capture a bat. Also, if a bite or physical which will produce easily observed contact occurs, capture the bat without dense smoke. Be careful of any fire damaging its head and immediately hazards. contact a physician (see previous The easiest time to seal bats out of section regarding rabies treatment). buildings in northern latitudes is dur- Management of problems involving ing the cooler part of the year when bat colonies require more complicated colonies are not resident. During this procedures and a greater time commit- period, many homeowners need to be ment. reminded that bats, and bat problems, Exclusion return each summer. Basic carpentry, masonry, and tinsmith skills are valu- Fig. 10. Using a clothes hanger/plastic film com- Preventive Aspects. The most satis- able in bat exclusion and other bination to detect air leaks. factory and permanent method of pestproofing interventions. managing nuisance bats is to exclude Devices and Methods. Exclusion The traditional way to exclude bats them from buildings. Locate bats and becomes “denial of reentry” once the from an occupied roost involves five their points of exit/entry through bat bats have returned to establish mater- basic steps: (1) identify and close all in- watches or other inspection methods. nity colonies (and before the young are door openings through which bats This is a tedious process to locate all born), usually from April through might gain access to human living openings in use, and bats may switch mid-May in the Northeast. Denial of quarters; (2) close most confirmed and to alternate ones when normal routes reentry is also appropriate anytime all unused potential exterior exits, become unavailable. Thus, consider after mid-August when young are leaving only a few major openings (it’s “potential” as well as “active” points capable of flying, as long as bats con- best to complete this within 1 to 2 of access. tinue to utilize the roost. days); (3) at night shortly after the bats Often it is apparent where bats might gain entrance even when such openings are not directly observable. By standing in various locations of a dark- ened attic during daylight hours, one often can find leaks of light at the extreme parts of eaves, in layers of subroofing, and below chimney flashings. Seal all gaps of 1/4 x 1 1/2 inches (0.6 x 3.8 cm) and openings 5/8 x 7/8 inch (1.6 x 2.2 cm) or greater. Bats will also use some of the same obscure holes in buildings through which heat (or cooled air) is lost; thus, bat-proofing often conserves energy. Simple, homemade devices can be used to locate air leaks. Bathroom tissue or very thin plastic film bags can be taped to a clothes hanger. When placed in front of an area with an air leak (for example, around window frames and sashes where caulking or weatherstripping are needed), the tis- Fig. 11. Smoke from the Sensidyne Air Indicator makes it possible to visually determine the direc- tional pattern of air currents.

D-18 have departed to feed, temporarily close the few remaining, major exits; (4) check the roost for presence of bats and, if any remain, unplug the temporarily closed exits early the next evening to allow the bats to escape, then temporarily replug the exits (it may be necessary to repeat this step more than once); and (5) when the bats are all out, permanently seal the holes (Frantz and Trimarchi 1984, Greenhall 1982). Patience and timing are very important in this process. Much of this work can be done during daylight hours except steps 3 and 4, which require climbing on ladders and roofs at night, Fig. 12. Bat on birdnetting showing size relationships. sometimes with bats flying nearby. The danger of such work is obvious To overcome difficulties with exclus- exit point — a single hole, a series of and discouraging. ion devices, Frantz’ checkvalve was holes, or a long slitlike opening (Fig. developed using netting made of Some of these difficulties have been 13). Designs must be open enough not durable black polypropylene resin overcome by use of the Constantine to impede the exiting bats. The top can (Frantz 1984, 1986). Quality of product one-way valvelike device which is be much larger than the bottom. It is is important since the netting should installed in the last exit(s) during the probably best to restrict the bottom not fray or become misshapen under day, and permits bats to leave after opening to no larger than about 1.6 x hot summer conditions. Use only dark but prevents their reentry (Con- 1.6 feet (0.5 x 0.5 m). The length of a structural grade material that has stantine 1982). Eventually the valve checkvalve, that is, the distance from openings no larger than 1/2 x 1/2 inch should be removed and the hole(s) the lowest enclosed point of egress to (1.3 x 1.3 cm), weighs about 1.3 ounces sealed. Another device, the EX-100 the bottom of the netting, should be per square yard (44 g/m2) and is flex- Hanks Bat Excluder, consists of a piece about 3.3 feet (1 m). ible yet stiff enough to maintain the of nylon window screening, a wooden The above specifications usually are shape of the checkvalve fabricated plate with a hole in the middle to sufficient to abort bats’ reentry at- (Fig. 12). Waterproof duct tape, com- which is attached a one-way plastic tempts. If netting is applied while mon staples, and/or wooden lath flappervalve, and a rigid plastic mesh young are still in the roost, the strips are used to attach the netting to cone (Anon. 1983). The screening, to “evicted” mothers may be motivated metal, slate, brick, wood, asphalt which the wooden plate is attached, is to chew holes in the netting to reenter shingle, or other surfaces. Note that used to cover an opening that bats use the roost. Applied at the correct time duct tape may stain or discolor to exit a building. Both devices are of year, however, netting will allow all painted/enameled surfaces if kept in designed to be used on the last few bats to exit at dusk and thereafter deny contact for long periods of time. exit points. Installation instructions are them reentry. available, and properly applied they Application of checkvalves follows the Checkvalves should be kept in place will undoubtedly exclude bats from same two initial steps as traditional bat for 3 to 5 days. It is best to verify (con- relatively small, discrete openings. exclusion. Close interior openings, duct a bat watch) that bats no longer then close exterior openings except a The devices of Constantine and Hanks exit at dusk before the checkvalves are few major exits. These latter openings involve a one-way, self-closing valve dismantled and the holes are sealed will have been confirmed as important feature and can be readily installed permanently. As in any exclusion via bat watches, and it is here that during daylight hours. Such devices intervention, the excluded animals will checkvalves will be fitted during the are not readily adaptable to situations go elsewhere. This shift may be to an daylight. with large, diffuse and/or widely dis- alternative roost already in use such as tributed entryways. Also, bats can be The basic design is to attach the netting a night roost, or one used in previous inadvertently trapped inside if an around an exit hole except at the bot- years. important exit hole is mistakenly iden- tom where the bats will escape (see tified as a minor one and is sealed in Frantz 1986, for details). The width Supplemental Materials and an attempt to limit the number of holes and shape of checkvalves is highly Methods. While specifications for requiring an exclusion device. variable so as to embrace the necessary Frantz’ checkvalve have been

D-19 expanding polyurethane foam applied from pressurized containers can be used for openings larger than 3 inches (>7.5 cm). It must be applied with Open-bottomed box designs for bat-proofing caution so as to not lift clapboards, roof apex, roof corner, and soffit/wall interface. shingles, and other surfaces. Exposed surfaces should be sealed with epoxy paint to prevent insect infestation and ultraviolet degradation. Conventional draft sweeps (metal, rubber) and other weatherstripping supplies (felt, vinyl, metal) will seal the space between a door bottom and the threshold or around windows (Fig. 14). Remember to treat attic and basement doors whenever the gap exceeds 1/4 inch (0.6 cm). Flashing may be used to close gaps wherever joints Sleeve design for bat-proofing fascia board/clapboard inter- occur; for example, where the roof face (without roof overhang). meets a chimney. Materials commonly used include galvanized metal, copper, aluminum, and stainless steel. Self- adhesive stainless steel “tape” is also available. Insulation will provide some degree of barrier to bat movements. It is available in a number of forms and types including fiberglass, rock wool, Skirt design for bat- urethane, vermiculite, polystyrene, proofing ridge cap of tin or tile roof. and extruded polystyrene foam. Inor- ganic materials are fire and moisture resistant; the safest appear to be fiberglass and rock wool. The mesh size of screening must be small enough to prevent access of bats and other species, where desired. Hardware cloth with 1/4-inch (0.6-cm) mesh will exclude bats and mice; screening with 16 meshes per inch (2.5 Fig. 13. Sample configurations for Frantz’ checkvalve (Key: = birdnetting; ...... = attaching to cm) will exclude most insects. Soffits structure; • = exit/entry holes of bats). (underside of overhanging eaves) usually have ventilators of various shapes and sizes. Regardless of type, the slots provided, additional caulking, crevices that develop in a house as it should not exceed 1/4 x 1 inch (0.6 cm flashing, screening, and insulation ages, and are best applied during dry x 2.5 cm) and should be covered inside materials often are needed. The periods when wood cracks are widest. with insect mesh. To prevent bats from combination of materials used will Caulks that may be applied with a entering chimney flues, completely depend on the location, size, and caulking gun (in gaps up to about 0.4 enclose the flue discharge area with number of openings, and the need for inch [1 cm] wide) include latex, butyl, rust-resistant spark arresters or pest ventilation. Greenhall (1982) provides and acrylic, which last about 5 years. screens, secured to the top of the many details of bat-proofing methods Elastomeric caulks, such as silicone chimney. These should not be perma- and materials and is a practical guide. rubber, will last indefinitely, expand nently attached (for example, with Weatherstripping, knitted wire mesh and contract, do not dry or crack, and screws) in case they must be rapidly (Guard-All®, Stuf-fit®), waterproof tolerate temperature extremes. Oakum removed in the event of a chimney duct tape, stainless steel wool, and packs easily and firmly into small fire. Review fire codes before installing wood lath may be used to block long, cracks. Other fillers include sponge flue covers. Dampers should be kept narrow openings. Caulk-ing rubber, glass fiber, knitted wire mesh, closed except in the heating season. compounds will seal cracks and and quick-setting putty. Self-

D-20 Roof Problems. Rolled vinyl Adhesive-backed foam rubber Bats, particularly the Mexican free-tailed bat, often roost under Spanish or concrete tile roofing by entering the open ends at the lower- most row or where the tiles overlap (Fig. 15). Tight-fitting plugs are difficult to make due to the variation in opening sizes and thermal expansion and contraction. A solution was found Outside Inside Ouside Inside by Constantine (1979) in which a layer of coarse fiberglass batting was laid Window sash Window sash under the tiles so that bats entering holes would contact the fiberglass and Windowsill Windowsill be repelled. A layer of knitted wire mesh would undoubtedly work well for this purpose (and would not hold moisture). Bats also may be excluded Inside Inside from the tiles if rain gutters are Doorjamb Doorjamb installed directly under the open ends. Door Door Gaps under corrugated and galvanized roofing may be closed with knitted wire mesh, self-expanding foam (avoid causing roofing to lift), or with Outside Outside fiberglass batting (may retain moisture). Door sweep Rubber or fitted to bottom plastic gasket Wall Problems. Fiberglass or rock of door fitted to wool insulation blown into wall spaces bottom of door that are used by bats may be a deter- Inside rent, especially when it forms a physi- Outside cal barrier to passage. Such work must be done when bats are absent to avoid Rubber or plastic Interlocking their entrapment. gasket fitted to metal doorsill Temporary Roosts. Bats will some- metal doorsill and door shoe times temporarily roost on porches and patios, in garages, and behind Inside Inside shutters, shingles, and roof gutters. Roosting behind shutters may also be long-term in duration. Actual control measures may not be necessary unless Fig. 14. Weatherstripping and door sweeps are very useful bat-proofing measures. bat droppings become a problem or the risk of human contact is significant. Coarse fiberglass batting tacked to the surfaces where bats prefer to hang sometimes discourages them. A poten- tially useful intervention for the wall- ceiling interface is the application of a wide 45o molding strip to eliminate the 90o angle corner and force the bats to roost in a more exposed area.

Repellents While many chemical aromatics and irritants have been proposed and tested for bat repellency, efficacy has been very limited thus far.

Fig. 15. Open ends of tile roofs may allow bat entry and provide roosting sites.

D-21 Naphthalene crystals and flakes are they fly toward an entrance hole Section 24(c) of the Federal Insecticide, the only repellents registered by the (Frantz, unpublished data). The results Fungicide, and Rodenticide Act D-18 US Environmental Protection Agency have not been promising. Numerous (FIFRA). Lipha Tech, Inc. (the manu- (EPA) for indoor bat control and are to ultrasonic devices have been removed facturer of RoZol ) has voluntarily can- be applied in attics or between walls. from clients’ homes because the bats celled its registration for “RoZol Sometimes the chemical may be placed remained in the roost after the devices Tracking Powder for Control of Nui- in loose-mesh cloth bags and sus- were activated. Hurley and Fenton sance Bats” — effective December 16, pended from the rafters. About 2.5 (1980) exposed little brown bats to ul- 1991 (Fed. Reg., 1991). pounds per 1,000 cubic feet (1.2 kg/30 trasound in seminatural roosts with m3) is recommended to chronically re- virtually no effect. Largely because of Trapping pel bats as the chemical vaporizes. this lack of known scientific efficacy Kunz and Kurta (1988) reviewed an Dosages of 5 pounds per 1,000 cubic for ultrasonic devices, the New York extensive variety of efficient methods feet (2.4 kg/30 m3) may dislodge bats State Consumer Protection Board has for trapping bats from buildings and in broad daylight. Bats will return, cautioned against the use of such other roosting sites or foraging areas. however, when the odor dissipates. devices (NYSCPB 1988). Part of the For purposes of wildlife damage The prolonged inhalation of naphtha- concern is that such devices will pro- control, however, exclusion is less lene vapors may be hazardous to vide consumers with a false sense of complicated to carry out, less time- human health. security and, thus, may prevent them consuming, more effective, and from taking effective preventive Illumination has been reported to be requires no handling of bats. actions. an effective repellent. Floodlights strung through an attic to illuminate Distress cries of bats recorded on tape Other Methods all roosting sites may cause bats to and rebroadcast can be used to attract Sanitation and Cleanup. Once bats leave. Large attics may require many other bats to nets or traps, but they do have been excluded, repelled, or have 100-watt bulbs or 150-watt spotlights not serve as an effective repellent. departed at the end of the summer, to be effective. Fluorescent bulbs may Little brown and big brown bats measures must be completed to make also be used. In some situations such respond to their own distress cries but reinfestation less likely, and to lighting is difficult, costly, and may not to the cries of other species. eliminate odor and problematic result in an electrical hazard. Where Contact repellents, such as sticky-type bioaerosols. As a prelude to such possible, the addition of windows to bird repellents and rodent glues, have work, it is sometimes useful to apply a brighten an attic will help to reduce been used successfully in situations pyrethrum-based, total-release aerosol the desirability of the roost site and is where roost surfaces and bat accesses insecticide to eliminate unwanted not likely to introduce additional may be coated. Apply masking tape to arthropods. problems. the surface first if you desire to remove The safe handling and removal of bat Air drafts have successfully repelled the repellent after treatment is fin- guano has been discussed previously bats in areas where it is possible to ished. Replenish contact repellents (see the histoplasmosis section in this open doors, windows, or create strong occasionally, since dust accumulation chapter). In addition to the more bulky breezes by use of electric fans. Addi- causes them to lose their tackiness. accumulations of excreta, there are tion of wall and roof vents will Also, caution must be exercised so as often diffuse deposits of guano under/ enhance this effort, as well as lower to apply coatings that will be sticky, among insulation materials, caked roost temperature. These measures but will not entrap the bats. urine and guano on roof beams, and will increase the thermoregulatory splattered urine on windows. Such Toxicants (not recommended) burden on the bats, thus making the clean-up work during hot summer roost less desirable. In a similar fash- No toxicants are registered for control- weather may be the least desirable ion, colonies located in soffits, behind ling bats. In 1987 the Centers for activity of a management program, but cornices, and other closed-in areas can Disease Control, United States Depart- it is necessary. be discouraged by opening these areas ment of Health and Human Services, All caked, crystallized bat urine and to eliminate dark recesses. Discourage voluntarily withdrew the last registra- droppings should be scraped and bats from roosting behind shutters by tion for DDT use against bats in the wire-brushed, as necessary, from all removing the shutters completely or United States. Thus, DDT is no longer roof and attic beams. For this proce- by adding small blocks at the corners registered for any use in this country. to space them a few inches away from dure, workers should take the same the wall. Although federally registered for precautions as outlined for histoplas- rodents, chlorophacinone (RoZol ) mosis-related work. Accumulated Ultrasonic devices have been tested tracking powder, an anticoagulant, is excreta and contaminated insulation under natural conditions, both indoors not registered for bats. Furthermore, it should be sealed in plastic bags and and outdoors, to repel little brown and can no longer be registered by indi- removed for disposal. Remove all big brown bats either in the roost or as vidual states for restricted use under remaining droppings and debris with

D-22 No figures are available to determine the extent of damage caused by nuisance bats or the cost for their control. The problem is widespread in this and other countries. Costs for remedial services are highly variable, depending on the nature of the problem and who will do the work. For example, to fabricate a few Frantz’ checkvalves on the “average” two-story house would probably require two workers about one-half day, mostly on stepladders, and less than $50 in materials. Much more time would be required to seal up all the other active and potential bat exit/ entry holes. In addition, if a deterio- rated roof, eaves, or other woodwork Fig. 16. One of five bat houses constructed to provide an alternative roost for bats excluded from must be replaced, the costs can nearby structures. increase rapidly. a vacuum cleaner, preferably one that Development of an efficient method to It is often difficult or expensive for the has a water filter to reduce the amount relocate bats into alternative roosts public to obtain the services of reliable, of dust that escapes from the cleaner’s after they have been excluded from licensed pest control operators (PCOs). exhaust. buildings could be an important inter- Many PCOs have limited knowledge vention in comprehensive bat manage- of basic bat biology and are apprehen- Where possible, wash with soap and ment. Frantz (1989) found it helpful to sive to work with bats. They may want water all surfaces contaminated with “seed” newly constructed bat houses to avoid any liabilities should bat- urine and guano. Allow the surfaces to with several bats, a procedure that human contact occur. Select a qualified dry, then disinfect them by misting or later resulted in full-scale colonization professional service that concentrates swabbing on a solution of 1 part without further human interventions. on the exclusion of live bats from a household bleach and 20 parts tap Alternative roosts should be located structure rather than on use of lethal water. Ventilate the roost site to allow away from human high-use areas. chemicals. odors and moisture to escape. Installa- Thus, people can enjoy the benefits of tion of tight-fitting window screens, bats without sharing their dwellings Acknowledgments roof and/or wall ventilators in attics with them and with little risk of direct will enhance this process. Remember, contact with them. The authors wish to thank the many people who sanitation and cleanup accompanies have allowed them and other bat researchers to bat-proofing and exclusion measures, work in and about their homes, and have, thus, it does not replace them. contributed to this effort. We give special thanks Economics of Damage to Roger W. Barbour and Wayne H. Davis for and Control permission to reproduce figures from their Artificial Roosts. For more than 60 excellent book, Bats of America (University Press years, artificial bat roosts have been of Kentucky). Charles V. Trimarchi is Virtually all bats are of some economic used in Europe. Only recently have acknowledged for carefully reviewing this importance; those north of Mexico are chapter and providing many useful comments. they gained some popularity in the beneficial because of their insectivo- We thank Debra VonZwehl and Christine United States. Though the results are rous diet which eliminates many insect Borecki for processing the manuscript. variable, it appears that artificial pests of humans. The accumulated bat Figures 2 through 4 from Barbour and Davis roosts, if properly constructed and droppings, called guano, is rich in (1979). located, can attract bats that are dis- nitrogen and is a good organic fertil- Figure 5 adapted from Harvey (1986). placed or excluded from a structure. izer. At one time, bat guano was com- The Missouri Department of Conser- Figure 6 adapted from Tuttle (1988), except Yuma mercially mined in the Southwest; but vation described a successful “bat ref- myotis and Keen’s bat (from Barbour and Davis its importance has declined due to 1979). uge” that was quickly occupied by a reduced bat populations and the displaced colony of little brown bats Figure 7 adapted from Trimarchi and Frantz (1985). development of inorganic fertilizers. (LaVal and LaVal 1980). Bat houses of Figure 8 by R. Suss. Bat guano is still considered a valuable a similar design have been successfully fertilizer resource in some parts of the Figures 12, 15, and 16 by S. C. Frantz. used in Minnesota, New York, and world (such as Thailand and Mexico). elsewhere (see Fig. 16). Figures 9, 10, 11, and 14 from Greenhall (1982) Figure 13 by S. C. Frantz

D-23 For Additional Geluso, K. N., J. Scott Altenbach, and R. C. NYSDH. 1990. Bat rabies in New York State. Kerbo. 1987. Bats of Carlsbad Caverns Publ. No. 3003, New York State Dep. Health, Information National Park. Carlsbad Caverns Natural Albany. 12 pp. Hist. Assoc., Carlsbad, New Mexico. 34 pp. Reid-Sanden, F. L., J. G. Dobbins, J. S. Smith, and Anonymous. 1983. Wisconsin firm develops bat George, R. B., and R. L. Penn. 1986. D. B. Fishbein. 1990. Rabies surveillance in excluder. Pest. Control Technol. 11:74. Histoplasmosis. Pages 69-85 in G. A. Sarosi the United States during 1989. Spec. Rep., J. and S. F. Davies, eds. Fungal diseases of the Am. Vet. Med. Assoc. 197:1571-1583. Anonymous. 1986. States focus on bat lung. Grune and Stratton, Inc., New York. conservation. Bats. 3(3): 3-4. Rippon, J. W. 1988. Histoplasmosis Greenhall, A. M. 1982. House bat management. (Histoplasmosis capsulatum). Pages 381-423 in Barbour, R. W., and W. H. Davis. 1979. Bats of Resour. Publ. No. 143. US Dep. Inter., Fish J. W. Rippon, ed. Medical mycology. W. B. America. Univ. Kentucky Press, Lexington. Wildl. Serv., Washington, DC. 33 pp. Saunders Co., New York. 286 pp. Harvey, M. J. 1986. Arkansas bats: a valuable Stebbings, B., and S. Walsh. 1985. Bat boxes. Barclay, R. M. R., D. W. Thomas, and M. B. resource. Arkansas Game Fish Comm., Little Fauna and Floral Preserv. Soc., London. Fenton. 1980. Comparison of methods used Rock. 48 pp. 16 pp. for controlling bats in buildings. J. Wildl. Manage. 44: 501-506. Hill, J. E., and J. D. Smith. 1984. Bats: A natural Trimarchi, C. V. 1987. Rabies transmission from history. Univ. Texas Press, Austin. 243 pp. bats to terrestrial mammals: evidence of CDC. 1977. Histoplasmosis control. US Dep. frequency and significance. Bat Res. News. Health, Educ. and Welfare, Centers for Hurley, S., and M. B. Fenton. 1980. 28(3-4):38. Disease Control, Atlanta, Georgia. 10 pp. Ineffectiveness of fenthion, zinc phosphide, DDT and two ultrasonic rodent repellers for Trimarchi, C. V., M. K. Abelseth, and R. J. Rudd. Constantine, D. G. 1979. Bat rabies and bat control of populations of little brown bats 1979. Aggressive behavior in rabid big management. Bull. Soc. Vector Ecol. 4:1-9. (Myotis lucifugus). Bull. Environ. Contam. brown bats (Eptesicus fuscus). Pages 34-35 in Constantine, D. G. 1982. Bat-proofing of Toxicol. 25:503-507. Rabies Information Exchange, No. 1. US Dep. buildings by installation of valve-like Human Health Services, Centers for Disease Krebs, J. W., R. C. Holman, U. Hines, T. W. devices in entryways. J. Wildl. Manage. Control, Atlanta, Georgia. Strine, E. J. Mandel, and J. E. Childs. 1992. 46:507-513. Rabies surveillance in the United States Trimarchi, C. V., and S.C. Frantz. 1985. Bat Dalquest, W. W., and D. W. Walton. 1970. during 1991. Special Report, J. Am. Veterin. control. New York State Dep. Health Diurnal retreats of bats. Pages 162-187, in B. Med. Assoc. 201 (12):1836-1848. Pamphlet, Albany. 6 pp. H. Slaughter and D. W. Walton, eds. About Kunz, T. H. 1982. Roosting ecology of bats. Tuttle, M. D. 1988. America’s neighborhood bats. Southern Methodist Univ. Press, Dallas, Pages 1-55 in T. H. Kunz, ed. Ecology of bats. bats. Univ. Texas Press, Austin. 96 pp. Texas. Plenum Press, New York. Tuttle, M. D., and D. Stevenson. 1982. Growth Fed. Reg., 1991. Notices, Federal Register/ Kunz, T. H., and A. Kurta. 1988. Capture and survival of bats. Pages 105-150 in T.H. August 28, 1991. 56(167):42615, 42620, and methods and holding devices. Pages 1-29 in Kunz, ed. Ecology of bats. Plenum Press, 42621. T.H. Kunz, ed. Ecological and behavioral New York. Fenton, M. B. 1983. Just bats. Univ. Toronto methods for the study of bats. Smithsonian US EPA. 1980. Re. Bradley Exterminating Press, Toronto. 165 pp. Inst. Press, Washington, DC. Company, Richfield, MN, Dockett No. I. Frantz, S. C. 1984. Excluding housebats with Laidlaw, W. J., and M. B. Fenton. 1971. Control F&R. V-604-C, May 8, 1980. US Environ. birdnetting. Bat Res. News. 25(3/4):40-41. of nursery colony populations of bats by Protect. Agency, Kansas City, Missouri. artificial light. J. Ecol. Manage. 35:843-46. 50 pp. Frantz, S. C. 1986. Bat-proofing structures with birdnetting checkvalves. Proc. Vertebr. Pest LaVal, R. K., and M. L. LaVal. 1980. Ecological Wimsatt, W. A. 1970. Biology of bats. Vol. II. Conf. 12:260-268. studies and management of Missouri bats Academic Press, New York. 477 pp. with emphasis on cave-dwelling species. Frantz, S. C. 1987. Chlorophacinone, DDT and Missouri Dep. Conserv. Terr. Ser. 8. 53 pp. other pesticides for bat control: efforts to prohibit use in New York State. Bat Res. Lera, T. M., and S. Fortune. 1979. Bat News. 28(3-4): 34. management in the United States. Bull. Nat. Editors Speleol. Soc. 41:3-9. Frantz, S. C. 1988. Architecture and commensal Scott E. Hygnstrom vertebrate pest management. Pages 228-295 NASPHV. 1993. Compendium of animal rabies Robert M. Timm in R. B. Kundsin, ed. Architectural design control, 1993. Natl. Assoc. State Publ. Health Gary E. Larson and indoor microbial pollution. Oxford Vet., Inc. Texas Dep. Health, Austin. 4 pp. Univ. Press, New York. NPCA. 1991. Controlling bats. Technical Release Frantz, S. C. 1989. Bat houses in state parks: an ESPC 043233A, 11/13/91. Natl. Pest. experiment in New York. Bats. 7:14. Control. Assoc., Dunn Loring, Virginia. 4 pp. Frantz, S. C., and C. V. Trimarchi. 1984. Bats in NYSCPB. 1988. The quest for the pest. Consumer human dwellings: health concerns and News (July 4, 1988), pp. 29, 30. management. Proc. Eastern Wild. Damage Control Conf. 1:299-308.

D-24 Scott R. Craven Extension Wildlife Specialist Department of Wildlife Ecology DEER University of Wisconsin-Madison Madison, Wisconsin 53706

Scott E. Hygnstrom Extension Wildlife Damage Specialist Department of Forestry, Fisheries and Wildlife University of Nebraska Lincoln, NE 68583

Fig. 1. White-tailed deer, Odocoileus virginianus

Damage Prevention and Harvest crops as early as possible to a few, such as Deer-Away®, possess Control Methods reduce vulnerability. characteristics of both groups. Lure crops may divert deer away from Toxicants Exclusion areas that are susceptible to None are registered. damage. Fences provide the most consistent Live Capture control: Habitat modification generally is not 8-foot (1.4-m) woven wire fence, recommended. Deer can be live-trapped or chemically immobilized for removal by Tensar®, or wooden snow fence Frightening around small plots or haystacks. professional biologists--useful only Gas exploders, pyrotechnics, gunfire, in special cases, such as city parks. Several configurations of electric or tethered dogs provide temporary fences are available: Shooting relief. vertical five, seven, or nine-wire, Sport hunting can reduce deer Repellents slanted seven-wire, single strand, populations and should be and others. A wide variety of commercial encouraged. formulations is available: Individual tree protectors include: Some states may issue permits to shoot area repellents--applied near plants woven wire or plastic cylinders. deer outside normal sport hunting to be protected, repel by smell; Cultural Methods and Habitat seasons. Modification contact repellents--applied directly to plants to be protected, repel by Plant trees and shrubs that are taste; resistant or less susceptible to deer damage.

D-26 Range

The white-tailed deer is found in every state in the United States except perhaps Alaska and Utah. It occurs throughout the southern provinces of Canada, across the United States, and on into Central and South America (Fig. 3). Mule deer are common throughout western Canada, western United States, and into Mexico (Fig. 4). There are several subspecies of both deer.

Fig. 3. Range of the white-tailed deer in North America.

Fig. 4. Range of the mule deer (light) and black- tailed deer (dark) in North America.

D-27 Habitat General Biology, Damage and Damage Reproduction, and Identification Deer are creatures of the forest edge Behavior rather than the dense, old-growth for- Deer damage a wide variety of row est. They thrive in agricultural areas crops, forage crops, vegetables, fruit Breeding occurs from October to Janu- interspersed with woodlots and ripar- trees, nursery stock, and ornamentals, ary depending on latitude. Peak activ- ian habitat. They favor early succes- as well as stacked hay. In addition to ity is in November. Does are in heat sional stages which keep brush and the immediate loss of the crop being for 24 hours every 28 days for 2 to 3 sapling browse within reach. Dense damaged, there is often residual dam- consecutive cycles. One buck may cover is used for winter shelter and age in the form of future yield reduc- inseminate several does. No pairing protection. tion of fruit trees or forage crops such takes place. Most does breed during as alfalfa. Ornamental trees or nursery their second fall, although on good stock may be permanently disfigured Food Habits range up to 30% of the doe fawns (6 by deer browsing. Under high densi- months old) will be bred. Gestation is ties deer may severely impact native Browse (leaves, stems, and buds of about 202 days. The peak of fawn drop plant communities and impair regen- woody plants) is generally available all is in May or June. Most reproducing eration of some forest tree species. year and is a staple food for deer. An fawns give birth to a single fawn, but Besides vegetative damage, deer/ extensive review of food habits can be adult does typically bear twin fawns. vehicle collisions pose a serious risk to found in Hesselton and Hesselton Reproductive potential is very sensi- motorists, and deer have been impli- (1982) and in Mackie et al. (1982). Plant tive to nutrition. Fawns weigh 7 to 8 cated in the distribution and transmis- species vary considerably in quality pounds (3.2 to 3.6 kg) at birth and sion of Lyme disease. and regional availability, so a list is not increase in weight for 5 1/2 to 6 1/2 presented here. Forbs are eaten in years. Adult size varies with latitude. spring and summer when available. In northern states, a mature buck may Damage identification is not difficult. Fruits and nuts (especially acorns) are weigh 200 to 300 pounds (90 to 135 Because both mule deer and white- seasonally very important. Grasses are kg). A key deer buck (white-tailed tailed deer lack upper incisors, deer relatively unimportant. Agricultural deer subspecies) in Florida may weigh often leave a jagged or torn surface on crops--corn, soybeans, small grains, only 50 pounds (22.5 kg). Does average twigs or stems that they browse. Rab- alfalfa, vegetables, and fruit trees--are 25% to 40% less than bucks for all bits and rodents, however, leave a readily eaten when available. Local subspecies. clean-cut surface. In addition, deer food habits studies are available in Deer are most active in early morning tracks are very distinctive (Fig. 5). The most states--consult your local wildlife and evening. They have a home range height of damage from the ground (up agency. of several hundred acres (ha), but this to 6 feet [1.8 m]) often rules out any Nutrient requirements and the amount varies with season, sex, and habitat mammal other than deer. Deer often of food consumed vary with age of the quality. In northern areas, deer gather are observed “in the act” of causing animal, season, and the reproductive (“yard”) in dense cover for the winter. damage. cycle. Daily dry matter consumption They may move long distances from averages 2% to 4% of live body weight. summer range to a winter yard. Life Legal Status For adult bucks, daily consumption is expectancy is dependent on hunting greatest in spring and averages 4.4 to pressure and regulations. Records Deer are protected year-round in all 6.4 pounds (2.0 to 2.9 kg) of air-dry show whitetails living 20 years, states and provinces, with the excep- food per day. Consumption is about although 10 to 12 years is noteworthy tion of legal harvest during appropri- half that during winter. For does, in the wild. ate big-game hunting seasons. In cases greatest daily food consumption of severe or persistent damage, some occurs in early fall, just prior to the states may issue farmers special per- breeding season. mits to shoot deer at times other than the legal hunting seasons. Regulations 3" 2 1/2" vary on the necessary permits and on

13" to 20" hind food front foot walking Fig. 5. Deer tracks

D-28 disposal of dead animals. The popular- expensive. You should consider sev- Temporary Electric Fencing ity of deer as game animals and the eral points before constructing a fence, Temporary electric fences provide in- need to curb poaching have led to the such as: expensive protection for many crops development of severe penalties for History of the area — assemble infor- during periods without snow. They illegal possession. No lethal deer con- mation on past claims, field histo- are easy to construct, do not require trol can be initiated before consulting ries, deer numbers, and movements rigid corners, and materials are readily your local state wildlife agency. By to help you decide on an abatement available. Install fences at the first sign law, some states provide technical method. of damage to prevent deer from estab- assistance or direct compensation for lishing feeding patterns in your crops. deer damage. This is discussed under Deer pressure — this reflects both the Weekly inspection and maintenance the section on the economics of dam- number of deer and their level of are required. Different types of tempo- age and control. dependence on agricultural crops. If rary electric fences are described deer pressure in your area is high, below. Damage Prevention and you probably need fences. Peanut Butter Fence. The peanut Control Methods Crop value — crops with high market butter fence is effective for small gar- values and perennial crops where dens, nurseries, and orchards (up to 3 Exclusion damage affects future yields and to 4 acres [1.2 to 1.6 ha]) subject to growth often need the protection Where deer are abundant or crops are moderate deer pressure. Deer are fencing can provide. particularly valuable, fencing may be attracted by the peanut butter and the only way to effectively minimize Field size — in general, fencing is prac- encouraged to make nose-to-fence con- deer damage. Several fencing designs tical for areas of 40 acres (16 ha) or tact. After being shocked, deer learn to are available to meet specific needs. less. The cost per acre (ha) for fenc- avoid fenced areas. Cost, excluding Temporary electric fences are simple ing usually decreases, however, as labor, is about $0.11 per linear foot inexpensive fences useful in protecting the size of the area protected in- ($0.30/m). This fence is not widely garden and field crops during snow- creases. used. free periods. Deer are attracted to these fences by their appearance or Cost-benefit analysis — to determine To build a peanut butter fence (Fig. 6), smell, and are lured into contacting the the cost effectiveness of fencing and follow the steps below. the type of fence to install, weigh fence with their noses. The resulting (1) Install wooden corner posts. shock is a very strong stimulus and the value of the crop to be protected deer learn to avoid the fenced area. against the acreage involved, costs (2) String one strand of 17-gauge Permanent high-tensile electric fences of fence construction and mainte- (0.15-cm), smooth wire around the provide year-round protection from nance, and the life expectancy of the corners and apply light tension. fence. deer and are best suited to high-value (3) Set 4-foot (1.2-m) 3/8-inch (1-cm) specialty or orchard crops. The electric Rapidly changing fence technology — round fiberglass rods along the shocking power and unique fence if you intend to build a fence your- wire at 45-foot (14-m) intervals. designs present both psychological self, supplement the following di- (4) Attach the wire to insulators on and physical barriers to deer. Perma- rections by consulting an expert, the rods 2 1/2 (0.75 m) feet above nent woven-wire fences provide the such as a fencing contractor. ground level and apply 50 pounds ultimate deer barrier. They require Detailed fencing manuals are also (22.5 kg) of tension. little maintenance but are very expen- available from most fencing manu- sive to build. Fencing in general is facturers and sales representatives.

3" x 4" Foil Adhesive tape Peanut butter Finished flags +

3' 2 1/2' Fence charger Power Grd

50'

6' Ground rod Fig. 6. The peanut butter fence with foil flags.

D-29 +

+ Fence charger Grd

60'

Fig. 7. The polytape fence.

(5) Attach 3 x 4-inch (7 x 10-cm) foil vegetable and field crops under mod- To maintain the fence, check it weekly strips to the wire at 3-foot (1-m) erate deer pressure. Deer receive for damage by deer and grounding by intervals, using 1 x 2-inch (3 x 5- shocks through nose-to-fence contact vegetation. cm) strips of cloth adhesive tape. and they learn to avoid fenced areas. Cost, excluding labor, is about $.11 per Permanent High-Tensile Electric (6) Apply a 1:1 mixture of peanut but- linear foot ($0.30/m). Fencing ter and vegetable oil to the adhesive tape strips and fold the foil To build a polytape fence (Fig. 7), fol- High-tensile fencing can provide year- over the tape. low the steps below. round protection from deer damage. Many designs are available to meet (7) Connect the wire to the positive (1) Drive 5/8-inch (1.6-cm) round specific needs. All require strict adher- (+) post of a well-grounded fence fiberglass posts 2 feet (0.6 m) into ence to construction guidelines con- charger. the ground at the corners. cerning rigid corner assemblies and (8) For fields larger than 1 acre (0.4 (2) String two strands of polytape fence configurations. Frequent inspec- ha), it is more practical to apply (white or yellow are most visible) tion and maintenance are required. the peanut butter mixture directly around the corners and apply light High-tensile fences are expected to last to the wire. You can make a tension (one strand 2 1/2 feet (0.75 20 to 30 years. Different types of high- simple applicator by mounting a m) high can be used). tensile electric fences are described free-spinning, 4-inch (10-cm) pul- below. (3) Use square knots or half-hitches to ley on a shaft inside a plastic ice make splices or to secure the Offset or Double Fence. This fence cream pail. Fill the pail with a pea- polytape to corner posts. is mostly for gardens, truck farms, or nut butter-vegetable oil mixture nurseries up to about 40 acres (0.16 ha) that has the consistency of very (4) Set 4-foot (1.2-cm) 3/8-inch (1-cm) that experience moderate deer pres- thick paint. Coat the entire wire round fiberglass rods along the sure. Deer are repelled by the shock with peanut butter by drawing the wires at 45-foot (14-m) intervals. and the three-dimensional nature of pulley along the wire. Apply pea- (5) Attach the two strands of polytape the fence. You can add wires if deer nut butter once a month. Attach to insulators on the rods at 1 and 3 pressure increases. Cost, excluding foil flags to the fence near runways feet (0.3 and 0.9 m) above ground labor, is about $.35 per linear foot or areas of high deer pressure to level and apply 50 pounds (22.5 ($1/m). make the fence more attractive. kg) of tension. To build an offset or double fence (Fig. Check the fence weekly for damage by (6) Connect the polytape to the posi- 8), follow the steps below. deer and grounding by vegetation. tive (+) post of a well-grounded For the outside fence: fence charger. Polytape Fence. Various forms of (1) Install swing corner assemblies (7) Use the applicator described polytape or polywire, such as Visible where necessary (see the section under Peanut Butter Fence (8) to Grazing Systems® (VGS), Baygard®, on fence construction—rigid apply 2-foot (0.6-m) swatches of and Turbo-tape® are very strong and brace assemblies [Fig. 14]). peanut butter to the polytape portable. You can use these fences to every 6 feet (2 m) where deer (2) String a 12 1/2-gauge (0.26-cm) protect up to 40 acres (16 ha) of presence is expected to be high. high-tensile wire around the

D-30 Tension spring + + 43" 30" Tensioners 38" + 15" 50' 52" Deer side

Fig. 8. The offset or double fence.

outside of the swing corner assem- (8) Attach the wire to insulators on space than three-dimensional fences, blies and apply light tension. the line posts at 30 inches (76 cm) but are probably less effective at inhib- above ground level. iting deer from jumping over fences. (3) Set 5-foot (1.5-m) line posts along There is a wide variety of fence materi- the wire at 40- to 60-foot (12- to 18- (9) Attach all wires to the positive (+) als, wire spacings, and specific designs m) intervals. post of a well-grounded, low- you can use. We recommend that you impedence fence charger. (4) Attach the wire to insulators on employ a local fence contractor. Costs, the line posts, 15 inches (38 cm) (10) Clear and maintain a 6- to 12-foot excluding labor, range from $0.75 to above ground level and apply 150 (1.8- to 3.6-m) open area outside $1.50 per linear foot ($2 to $4/m). to 250 pounds (68 to 113 kg) of the fence so deer can see it. To build a 7-wire vertical deer fence tension. Maintenance includes weekly fence (Fig. 9), follow the steps below. (5) String a second wire at 43 inches and voltage checks. (1) Install rigid corner assemblies (109 cm) and apply 150 to 250 Vertical Deer Fence. Vertical fences where necessary (see the section pounds (68 to 113 kg) of tension. are effective at protecting large truck on fence construction—rigid brace For the inside fence: gardens, orchards, and other fields assemblies [Fig. 14]). from moderate to high deer pressures. (6) String a wire around the inside of (2) String a 12 1/2-gauge (0.26-cm) Because of the prescribed wire spac- the swing corner assemblies and high-tensile wire around the ing, deer either attempt to go through apply light tension. corner assemblies and apply light the fence and are effectively shocked tension. (7) Set 5-foot (1.5-m) line posts along or they are physically impeded by the the wire at 40- to 60-foot (12- to 18- barrier. Vertical fences use less ground (3) Set 8-foot (2.4-m) line posts along m) intervals.

10' Wood post 8' Line post 10' Wood post — 12" + 12" — 12" + 10" + 33' 10" — 8" 33' + 8"

33'

Fig. 9. The seven-wire vertical deer fence.

D-31 Battens + — 12" + — 12" + 12" — 30' + 12"

12" 30' Crop side 12" 10" 30'

Corner post Corner post

12" 5'

7" 10" 10"

8' Corner post (Side view) (Top view) Fig. 10. The slanted seven-wire deer fence.

the wire at 33-foot (10-m) inter- Slanted Seven-Wire Deer Fence. (5) Attach the remaining wires at 12- vals. This fence is used where high deer inch (30-cm) intervals and apply pressures threaten moderate-to-large 150 pounds (68 kg) of tension. (4) Attach a wire to insulators at 8 sized orchards, nurseries and other inches (20 cm) above ground level (6) Place fence battens at 30-foot (9-m) high-value crops. It presents a physical and apply 150 to 250 pounds (68 to intervals. and psychological barrier to deer 113 kg) of tension. because of its electric shock and three- (7) Connect the top, third, fifth, and (5) Attach the remaining wires to in- dimensional nature. Cost, excluding bottom wires to the positive (+) sulators at the spacing indicated in labor, is about $0.75 to $2 per linear post of a well-grounded, low- figure 9 and apply 150 to 250 foot ($2 to $5.50/m). impedence fence charger. pounds (68 to 113 kg) of tension. To build a slanted seven-wire deer (8) Connect the second, fourth, and (6) Connect the second, fourth, fifth, fence (Fig. 10), follow the steps below. sixth wires from the top directly to and seventh wires from the top, to ground. (1) Set rigid, swing corner assemblies the positive (+) post of a well- where necessary, (see the section (9) Clear and maintain a 6- to 12-foot grounded, low-impedence fence on fence construction—rigid brace (1.8- to 3.6-m) area outside the charger. assemblies [Fig. 14]). fence so deer can see it. (7) Connect the top, third, and sixth (2) String 12 1/2-gauge (0.26-cm) Maintenance includes weekly inspec- wires directly to ground. The top high-tensile wire around the cor- tion and voltage checks. wire should be negative for light- ner assemblies and apply light ning protection. tension. Permanent Woven-Wire Fencing (8) Clear and maintain a 6- to 12-foot (3) Set angle braces along the wire at Woven-wire fences are used for year- (1.8- to 3.6-m) open area outside 90-foot (27-m) intervals. round protection of high-value crops the fence so deer can see the fence. subject to high deer pressures. These (4) Attach a wire at the 10-inch (25- Maintenance includes weekly fence fences are expensive and difficult to cm) position and apply 150 inspection and voltage checks. construct, but easy to maintain. Before pounds (68 kg) of tension.

D-32 high-tensile electric fencing, woven- (7) Attach two strands of high-tensile Association (CSA). We highly rec- wire fences were used most often to smooth wire to the top of the fence ommend 110-volt chargers. Six- protect orchards or nurseries where to raise the height of the entire and 12-volt chargers require bat- the high crop value, perennial nature fence to 9 to 10 feet (2.7 to 3 m). tery recharging every 2 to 4 weeks. of damage, acreage, and 20-year life Use solar panels in remote areas to Minimal maintenance is required. span of the fences justified the initial charge batteries continuously. For Inspect for locations where deer can costs. Cost, excluding labor, is about high-tensile fences, use high-volt- crawl under the fence. $2 to $4 per linear foot ($5.50 to age, low-impedence chargers only $11/m). The high cost has resulted in Fencing Tips (3,000 to 5,000 volts and current reduced use of woven-wire fences. pulse duration of at most 1/1,000 Materials. Do not buy cheap materi- second). To build a deer-proof woven-wire als to reduce costs. This will only re- fence (Fig. 11), follow the steps below. duce the effectiveness and life span of (6) Gates. There is no universal gate design because of the many differ- (1) Set rigid corner assemblies where the fence. We recommend using: ent fence types. Gates should be necessary (see the section on Fence (1) Round fiberglass or treated wood electrified, well-insulated, and Construction—Rigid brace assem- posts. practical for the type of farming blies [Fig. 14]). (2) High-quality galvanized wire and operation. Gates range from single (2) String a light wire between two steel components. For high-tensile strands of electrified wire with corners and apply light tension. fences, use 11- to 14-gauge (0.31- gate handles to electrified panel or tubular gates (Fig. 12). (3) Set 16-foot (4.9-m) posts along the to 0.21-cm) wire (minimum tensile wire at 40-foot (12-m) intervals, to strength of 200,000 pounds [90,000 Fence Construction. Fences must be a depth of 4 to 6 feet (1.2 to 1.8 m). kg] and a minimum breaking properly constructed--do not deviate strength of 1,800 pounds [810 kg]), from fence construction guidelines. (4) Roll out an 8-foot (2.4-m) roll of tension springs, and in-line high-tensile woven wire along the tensioners. (1) Prepare fencelines before construc- line posts. Attach one end at tion. It is easier and less expensive ground level to a corner post with (3) Compression sleeves for splicing to install and maintain fences on steel staples. wires and making electrical con- clear, level runs. Minimize corners nections. to increase strength and reduce (5) Apply 100 pounds (45 kg) of ten- costs. sion to the wire with a vehicle or (4) Lightning arresters and diverters fence strainers and attach the wire to protect chargers. (2) Ensure that the electrical system is to line and corner posts with steel (5) High-quality fence chargers. well grounded at the fence charger staples. Chargers must be approved by and every 1/2 mile (880 m) of fenceline. To ground high-tensile (6) Repeat steps 4 and 5 as necessary Underwriters Laboratories (UL) fences, drive four to six ground around the perimeter of the fence. or the Canadian Standards

HTHT smooth smooth wire wire TensionersTensioner andTension tension spring spring

10'10'

40'

Fig. 11. The deer-proof, woven-wire fence.

D-33 — + + + — +

+ +

Fig. 12. Fence with electrified gate.

rods 5 to 6 feet (1.5 to 1.8 m) deep parts of the fence when you are Fence flexibility is necessary to and 6 feet (1.8 m) apart. Connect not working on the fence to gain endure frequent temperature the ground post of the fence early protection. changes, deer hits, and obstruc- charger and the negative (-) wires tions. (5) Rigid brace assemblies—corners, of the fence to the grounding sys- ends, and gates—make up the (7) Identify an electric fence with tem (Fig. 13). backbone of all high-tensile fence warning signs (Fig. 15) that are (3) The wiring system in figure 13 systems (Fig. 14). They must be en- affixed at 300-foot (90-m) intervals illustrates a positive-negative tirely rigid, constructed of the best or less. fence. Such a design is especially materials, and strictly conform to Maintenance. Regular inspection and useful with dry or frozen ground. design guidelines. The single-span maintenance are necessary to ensure A fence with all positive (hot) brace assembly is the basis of all the effective operation and longevity wires may be advantageous under high-tensile strainer assemblies, of most fences. general crop and soil moisture regardless of location in the fence conditions. Consult with a fencing or fence design. This basic design (1) Control vegetation near fences by contractor or expert for the best is then modified to create double- mowing or applying herbicides to choice for your needs. ”H” braces, swing corners, and avoid excessive fence grounding gate ends. by weeds. (4) Install the grounding systems and fence charger before fence con- (6) Allow wires to slide freely (2) On slopes or highly erodible soils, struction. Energize completed through insulators on fence posts. maintain a good sod cover

—

— Fence charger +

Power Ground

6' Ground rods

Fig. 13. Electrical and grounding system for high tensile fences. 6'

D-34 Direction of pull 8' X 4" Horizontal 9" Brace pin brace post WARNING

1" Lean ELECTRIC FENCE

6' Two wraps Twitch stick of HT wire

Fig. 15. Remember to attach warning signs to your electric fences.

4' 10' X 5" Post drive 4' beneath fences to avoid fenceline erosion. Single span brace assembly (3) Always keep the fence charger on. Check the fence voltage weekly with a voltmeter. Maintain at least 3,000 volts at the furthest distance from the fence charger. Disconnect the lower wires if they are covered by snow. (4) In late fall and early summer, adjust the fence tension (150 to 250 pounds [68 to 113 kg]) for high- tensile fences.

Tree Protectors Use Vexar®, Tubex®, plastic tree wrap, Swing corner or woven-wire cylinders to protect (vertical fence) young trees from deer and rabbits. Four-foot (1.2-m) woven-wire cylinders can keep deer from rubbing tree trunks with their antlers.

Haystack Protection Wooden panels have traditionally been used to exclude deer and elk from haystacks. Stockyards have also been protected by welded wire panels and woven wire. More recently haystacks have been protected by wrapping them with plastic Tensar® snow fence. The material comes in 8-foot (2.4-m) rolls and is relatively light and easy to use. Double H brace assembly (corner) Cultural Methods and Habitat Modification Damage to ornamental plants can be Fig. 14. Rigid brace assemblies. minimized by selecting landscape and garden plants that are less preferred by deer. In many cases, original landscape objectives can be met by planting species that have some resistance to

D-35 Table 1. Ornamental plants, listed by susceptibility to deer damage.1

Plants Rarely Damaged: Plants Occasionally Severely Damaged (cont.): Botanical name Common name Botanical name Comomn name Berberis spp. Barberry Ilex crenata Japanese Holly Berberis vulgaris Common Barberry Ilex (x) meserveae China Girl/Boy Holly Betula papyrifera Paper Birch Juniperus virginiana Eastern Red Cedar Buxus sempervirens Common Boxwood Larix decidua European Larch Elaeagnus angustifolia Russian Olive Lonicera (x) heckrottii Goldflame Honeysuckle Ligustrum spp. Ilex opaca American Holly Privet Magnolia (x) soulangiana Saucer Magnolia Leucothoe fontanesiana Drooping Leucothoe Metasequoia glyptostroboides Dawn Redwood Picea pungens Colorado Blue Spruce Parthenocissus quinquifolia Virginia Creeper Pieris japonica Japanese Pieris Philadelphus coronarius Sweet Mock Orange Plants Seldom Severely Damaged: Pinus strobus Eastern White Pine Potentilla fruticosa Bush Cinquefoil Botanical name Common name Prunus avium Sweet Cherry Betula pendula European White Birch Pseudotsuga menziesii Douglas Fir Calastrus scandens American Bittersweet Pyracantha coccinea Firethorn Cornus sericea Red Osier Dogwood Pyrus calleryana ‘Bradford’ Bradford Callery Pear Cornus florida Flowering Dogwood Pyrus communis Common Pear Cornus kousa Kousa Dogwood Quercus alba White Oak Crataegus laevigata English Hawthorn Quercus prinus Chestnut Oak Enkianthus campanulatus Redvein Enkianthus Quercus rubra Northern Red Oak Fagus sylvatica European Beech Rhododendron spp. Deciduous Azaleas Rhododendron carolinianum Carolina Rhododendron Forsythia spp. Forsythia Rhododendron maximum Rosebay Rhododendron Gleditsia triacanthos Honey Locust Rhus typhina Staghorn Sumac Ilex cornuta Chinese Holly Rosa multiflora Multiflora Rose Ilex glabra Inkberry Rosa rugosa Rugosa Rose Juniperus chinensis Chinese Junipers (green) Salix spp. Willows Juniperus chinensis Chinese Junipers (blue) Spiraea (x) bumalda Anthony Waterer Spiraea Kalmia latifolia Mountain Laurel Spiraea prunifolia Bridalwreath Spiraea Kolkwitzia amabilis Beautybush Syringa (x) persica Persian Lilac Picea abies Norway Spruce Syringa reticulata Japanese Tree Lilac Picea glauca White Spruce Syringa villosa Late Lilac Pinus nigra Austrian Pine Tilia cordata ‘Greenspire’ Greenspire Littleleaf Linden Pinus rigida Pitch Pine Tilia americana Basswood Pinus mugo Mugo Pine Tsuga canadensis Eatsern Hemlock Pinus resinosa Red Pine Tsuga caroliniana Carolina Hemlock Pinus sylvestris Scots Pine Viburnum (x) juddii Judd Viburnum Viburnum rhytidophyllum Leatherleaf Viburnum Prunus serrulata Japanese Flowering Cherry Viburnum plicatum tomemtosum Doublefile Viburnum Salix matsudana tortuosa Corkscrew Willow Viburnum carlesii Koreanspice Viburnum Sassafras albidum Common Sassafras Weigela florida Oldfashion Weigela Syringa vulgaris Common Lilac Wisteria floribunda Japanese Wisteria Plants Frequently Severely Damaged: Plants Occasionally Severely Damaged: Botanical name Common name Abies balsamea Balsam Fir Botanical name Common name Abies fraseri Fraser Fir Abies concolor White Fir Acer platanoides Norway Maple Acer griseum Paperbark Maple Cercis canadensis Eastern Redbud Acer rubrum Red Maple Chamaecyparis thyoides Atlantic White Cedar Acer saccharinum Silver Maple Clematis spp. Clematis Acer saccharum Sugar Maple Cornus mas Cornelian Dogwood Aesculus hippocastanum Common Horsechestnut Euonymus alatus Winged Euonymus Amelanchier arborea Downy Serviceberry Euonymus fortunei Wintercreeper Amelanchier laevis Allegheny Serviceberry Hedera helix English Ivy Campsis radicans Trumpet Creeper Malus spp. Apples Chaenomeles speciosa Japanese Flowering Quince Prunus spp. Cherries Cornus racemosa Panicled Dogwood Prunus spp. Plums Rhododendron spp. Rhododendrons Cotinus coggygria Smokebush Rhododendron spp. Evergreen Azaleas Cotoneaster spp. Cotoneaster Rhododendron catawbiense Catawba Rhododendron Cotoneaster apiculatus Cranberry Cotoneaster Rhododendron periclymenoides Pinxterbloom Azalea Cotoneaster horizontalis Rockspray Cotoneaster Rosa (x) hybrid Hybrid Tea Rose Cryptomeria japonica Japanese Cedar Sorbus aucuparia European Mountain Ash Forsythia (x) intermedia Border Forsythia Taxus spp. Yews Hamamelis virginiana Common Witchhazel Taxus baccata English Yew Hibiscus syriacus Rose of Sharon Taxus brevifolia Western Yew Hydrangea arborescens Smooth Hydrangea Taxus cuspidata Japanese Yew Hydrangea anomala petiolaris Climbing Hydrangea Taxus (x) media English/Japanese Hybrid Yew Hydrangea paniculata Panicle Hydrangea Thuja occidentalis American Arborvitae

1from M. J. Fargione, P. D. Curtis, and M. E. Richmond. 1991. Resistance of woody ornamental plants to deer damage. Cornell Coop. Ext. Fact Sheet. Ithaca, NY. 4 pp.

D-36 deer damage. Table 1 provides a list of to damage, for example, the silking to and shrubs during the dormant pe- plants, ranked by susceptibility to deer tasseling stages for field corn or the riod. New growth that appears after damage. This list, developed by blossom stage for soybeans. treatment is unprotected. Contact re- researchers at Cornell University, is pellents may reduce the palatability of Gas exploders set to detonate at regu- applicable for most eastern and north- forage crops and should not be used lar intervals are the most commonly ern states. A similar list with a western on plant parts destined for human con- used frightening devices for deer. emphasis was produced by Cummings sumption. Hinder® is an exception in They can be purchased for $200 to et al. (1980). that it can be applied directly on edible $500 from several commercial sources crops. Harvest crops as early as possible to (see Supplies and Materials). The reduce the period of vulnerability to devices are sometimes available on Area repellents are applied near the deer. Plant susceptible crops as far loan from wildlife refuges or agencies plants to be protected and repel deer from wooded cover as possible to as they are frequently used to control by odor alone. They are usually less reduce the potential for severe dam- waterfowl damage. To maximize the effective than contact repellents but age. Habitat modification is not recom- effectiveness of exploders, move them can be used in perimeter applications mended. Destruction of wooded or every few days and stagger the firing and some situations where contact brushy cover in hopes of reducing sequence. Otherwise, the deer quickly repellents cannot. deer use would destroy valuable habi- become accustomed to the regular pat- During the winter or dormant season, tat for other wildlife. Also, since deer tern. The noise level can be increased apply contact repellents on a dry day forage over a large area it is unlikely by raising exploders off the ground. when temperatures are above freezing. that all available deer cover would be Motion-activated firing mechanisms Treat young trees completely. It will be on a farmer’s or rancher’s land. are now being explored to increase the more economical to treat only the ter- effectiveness of exploders. Success Lure crops have been planted to attract minal growth of older trees. Be sure to depends on many factors and can deer away from highways and crop treat to a height of 6 feet (1.8 m) above range from good to poor. A dog on a fields where deer traditionally caused expected maximum snow depth. Dur- long run or restricted by an electronic damage. Their effectiveness has been ing the growing season, apply contact invisible fence system can keep deer variable and concern has been raised repellents at about half the concentra- out of a limited area, but care and that an artificial food source may even- tion recommended for winter use. feeding of the dog can be time- tually increase deer densities and consuming. Free-running dogs are not The effectiveness of repellents will resultant problems. Specific recom- advisable and may be illegal. depend on several factors. Rainfall will mendations are not yet available dissipate some repellents, so reappli- regarding plant selection, timing, and Shell crackers, fireworks, and gunfire cation may be necessary after a rain. proximity of lure crops. can provide quick but temporary relief Some repellents do not weather well from deer damage. Equip mobile units even in the absence of rainfall. Deer’s Contraception with pyrotechnics, spotlights, and two- hunger and the availability of other way radios. Patrol farm perimeters Promising research on the use of more palatable food will have a great and field roads at dusk and through- chemosterilants and immunocontra- effect on success. In times of food out the night during times of the year ception to reduce or eliminate repro- stress, deer are likely to ignore either when crops are most susceptible to duction is underway. Specificity, taste or odor repellents. When using a damage. Such tactics cannot be relied efficacy, and delivery of contraceptive commercial preparation, follow the on for an entire growing season. agents, however, continue to be prob- manufacturer’s instructions. Don’t lems. The use of contraception for herd Repellents overlook new preparations or imagina- control will be best suited to urban tive ways to use old ones. The follow- parks, refuges, and other discrete Repellents are best suited for use in or- ing discussion of common repellents is areas. It is unlikely that contraception chards, gardens, and on ornamental incomplete and provided only as a can or will be applied in rural/agricul- plants. High cost, limitations on use, survey of the wide range of repellent tural landscapes. and variable effectiveness make most formulations available. The repellents repellents impractical on row crops, are grouped by active ingredient. Frightening pastures, or other large areas. Success Trade names and sample labels for One of the keys to success with fright- with repellents is measured in the some products are provided in the ening devices and repellents is to take reduction, not total elimination, of Supplies and Materials section. action at the first sign of a problem. It damage. Deer-Away® Big Game Repellent is difficult to break the movements or Repellents are described by mode of behavioral patterns of deer once they actions as “contact” or “area.” Contact (37% putrescent whole egg solids). This have been established. Also, use fright- repellents, which are applied directly contact (odor/taste) repellent has been ening devices and repellents at those to the plants, repel by taste. They are used extensively in western conifer times when crops are most susceptible most effective when applied to trees plantations and reported in field

D-37 studiesto be 85% to 100% effective. It is and fruit trees. Apply the repellent Hair Bags (human hair). Human hair registered for use on fruit trees prior to with a backpack or trigger sprayer to is an odor (area) repellent that costs flowering, as well as ornamental and all susceptible new growth, such as very little but has not consistently Christmas trees. Apply it to all suscep- leaders and young leaves. Do not ap- repelled deer. Place two handfuls of tible new growth and leaders. Applica- ply to fruit-bearing plants after fruit hair in fine-mesh bags (onion bags, tions weather well and are effective for set. Vegetable crops also can be pro- nylon stockings). Where severe dam- 2 to 6 months. One gallon (3.8 l) of tected if sprayed prior to the develop- age occurs, hang hair bags on the outer liquid or 1 pound (0.45 kg) of powder ment of edible parts. Weatherability branches of individual trees with no costs about $32 and covers 400, 3-inch can be improved by adding an anti- more than 3 feet (0.9 m) between (7.6-cm) saplings or 75, 4-foot (1.2-m) transpirant such as Wilt-Pruf® or individual bags. For larger areas, hang evergreens. Vapor Gard®. Hot Sauce and Vapor several bags, 3 feet (0.9 m) apart, from Gard® cost about $80 and $30 per gal- a fence or cord around the perimeter Hinder® (15% ammonium soaps of lon (3.8 l) respectively. Eight ounces of the area to be protected. Attach the higher fatty acids). This area repellent is (240 ml) of Hot Sauce and two quarts bags early in spring and replace them one of the few registered for use on (1.9 l) of anti-transpirant mixed with monthly through the growing season. edible crops. You can apply it directly 100 gallons (380 l) of water will cover You can get hair at local barber shops to vegetable and field crops, forages, 1 acre (0.4 ha). or salons. ornamentals, and fruit trees. Its effectiveness is usually limited to 2 to 4 Tankage (putrefied meat scraps). Bar Soap. Recent studies and weeks but varies because of weather Tankage is a slaughterhouse by- numerous testimonials have shown and application technique. Reappli- product traditionally used as a deer that ordinary bars of soap applied in the same manner as hair bags can cation may be necessary after heavy repellent in orchards. It repels deer by reduce deer damage. Drill a hole in rains. For small fields and orchards, smell, as will be readily apparent. To each bar and suspend it with a twist you can treat the entire area. For larger prepare containers for tankage, remove the tops from aluminum tie or soft cord. Each bar appears to areas, apply an 8- to 15-foot (2.4- to protect a radius of about 1 yard (1 beverage cans, puncture the sides in 4.6-m) band around the perimeter of m). Any inexpensive brand of bar the middle of the cans to allow for the field. Apply at temperatures above soap will work. Ready-to-use bars o drainage and attach the cans to the 32°F (0 C). Four gallons (15.2 l) of cost about $0.20 each. liquid cost about $80, and when mixed ends of 4-foot (1.2 m) stakes. Drive the with 100 gallons (380 l) of water will stakes into the ground, 1 foot (0.3 m) Toxicants cover 1 acre (0.4 ha). Hinder is com- from every tree you want to protect or patible for use with most pesticides. at 6-foot (1.8-m) intervals around the No toxicants are registered for deer perimeter of a block. Place 1 cup (225 control. Poisoning of deer with any Thiram (7% to 42% tetramethylthiuram g) of tankage in each can. You can use product for any reason is illegal and disulfide). Thiram, a fungicide that acts mesh or cloth bags instead of cans. unlikely to be tolerated by the public. as a contact (taste) deer repellent, is You may have to replace the contain- sold under several trade names-- ers periodically because fox or other Herd Reduction Bonide Rabbit-Deer Repellent®, Nott’s animals pull them down occasionally. Overall reduction in a state’s deer Chew-Not, and Gustafson 42-S®, Tankage is available by bulk ($335 per population might reduce deer damage, among others. It is most often used on ton [$302/mt]) or bag ($20 per 50 but public opinion generally does not dormant trees and shrubs. A liquid pounds [22.5 kg]). When prepared for favor this approach. Damage may re- formulation is sprayed or painted on hanging on stakes, it costs about $0.20 sult from a few problem deer or at lo- individual trees. Although Thiram per 1 ounce (28 g) bag and 300 bags cations close to a winter deer yard or itself does not weather well, adhesives will cover 2 acres (0.8 ha). other exceptional habitat. Thus, a local such as Vapor Gard® can be added to reduction in deer population may be Ro-pel® (benzyldiethyl [(2,6 increase its resistance to weathering. appropriate. Thiram-based repellents also protect xylylcarbamoyl) methyl] ammonium saccharide (0.065%), thymol (0.035%). trees against rabbit and mouse dam- Live Capture age. Two gallons (7.6 l) of 42% Thiram Ro-pel® is reported to repel deer with cost about $50 and when mixed with its extremely bitter taste. Apply In special cases, such as city parks, ref- 100 gallons (380 l) of water will cover 1 Ro-pel® once each year to new growth. uges, or suburban neighborhoods, it acre (0.4 ha). Cost varies with the con- It is not recommended for use on may be necessary or desirable to centration of Thiram in the product. edible crops. Spray at full strength on capture deer alive and move them to nursery and Christmas trees, orna- other areas. Deer can be captured Miller’s Hot Sauce® Animal mentals, and flowers. One gallon (3.8 l) safely with rocket nets, drop-door box Repellent (2.5% capsaicin). This con- costs $50 and covers about 1 acre (0.4 traps, or tranquilizer guns, but these tact (taste) repellent is registered for ha) of 8- to 10-foot (2.4- to 3.0-m) trees. techniques are expensive, time- use on ornamentals, Christmas trees, consuming, and require the expertise

D-38 of professional wildlife biologists. Live Use of bait, spotlights, and rifles may Two additional economic aspects are capture and relocation is seldom a increase success but techniques must worth consideration. One involves practical alternative unless delicate be consistent with the specifications of farmer tolerance for deer damage. public relations problems mandate live the permits. In areas where shooting Two summaries of social science removal as the only choice. During normally is prohibited, such as parks research related to deer damage 1982, 15 deer were removed from a and densely populated areas, a skilled (Pomerantz et al. 1986, and Siemer and Milwaukee, Wisconsin nature area shooter under permit is probably pref- Decker 1991) demonstrated that a using chemical immobilization. Total erable to costly attempts at live re- majority of farmers were willing to tol- cost was about $100 per deer but other moval. erate several hundred dollars in deer more recent removal operations have damage in exchange for the various been more expensive, up to $400 per Economics of Damage benefits of having deer on their land. deer or more. In addition to high costs, and Control Thus “total damage” figures are mis- the survival of relocated deer is usu- leading because only a small percent- ally low. Live removal is seldom age of the farmers statewide or A national survey conducted by justified. nationwide are suffering sufficient USDA’s National Agricultural Statis- damage to warrant control or compen- tics Service in 1992 identified deer Shooting sation. damage as the most widespread form Effective use of the legal deer season is of wildlife damage. Forty percent of The second economic consideration probably the best way to control deer the farmers reporting had experienced involves state-funded programs of populations. By permitting hunting, deer damage. No estimate exists of subsidies for damage control materials landowners provide public access to a nationwide annual crop losses to deer, or direct compensation for crop losses. public resource while at the same time but damage estimates have been made Such programs can be very costly but reducing deer damage problems. for some states. In Wisconsin, a 1984 are probably necessary where large Because of the daily and seasonal survey of farmers suggested minimum deer herds are maintained in agricul- movements of deer, only rarely does a statewide deer damage of $36.7 million tural landscapes. As an example, the single landowner control all the land a annually. A similar study in Pennsyl- Wisconsin Wildlife Damage Program deer uses. As a result, neighboring vania estimated the annual crop loss at expended $2.25 million in 1992 for landowners should cooperate. Land- $16 to $30 million. The situation is abatement materials, claims, and owners, the state wildlife agency, and similar in most agricultural states with administration. The program is a col- local hunters should reach a consensus moderate to high deer densities. Esti- laborative effort of the Wisconsin about a desirable population level for mates by Hesselton and Hesselton Department of Natural Resources, an area before deer are removed. (1982) suggest that the cost of deer- USDA-APHIS-ADC, and Wisconsin vehicle collisions may exceed $100 mil- counties and is very effective. Indi- Mechanisms for managing deer popu- lion each year in the United States and vidual states vary greatly, however, in lation levels in a specific area already Canada. In fact, the cost of deer/ their degree of financial or technical exist in most states. Either-sex seasons, vehicle collisions was estimated at assistance. Consult your state wildlife increased bag limits, antlerless-only $100 million in Wisconsin alone in agency for information on compensa- permits, special depredation seasons, 1990. tion or cost-sharing programs. Also, and a variety of other management many states have local publications on Deer also damage nurseries, landscape techniques have been used success- deer and deer damage--Pennsylvania, plantings, and timber regeneration. fully to reduce deer numbers below Wisconsin, Minnesota, Michigan, and However, as established earlier, deer levels achieved by traditional “bucks New York, for example. Consult your are a valuable public resource. Cost only” regulations. local Extension office or state wildlife estimates for control techniques were agency. presented with the appropriate Shooting permits issued by some techniques. A cost/benefit analysis is states allow for removal of problem always advisable before initiating a deer where they are causing damage control program. during nonhunting season periods.

D-39 Acknowledgments Gallagher, B. 1992. 9th international power Selders, A. W., J. B. McAnninch, and R. J. fence manual. Gallagher Power Fence, Inc., Winchcombe. 1981. High-tensile wire San Antonio, Texas. 45 pp. fencing. Northeast Regional Agric. Eng. Serv. Figures 1 and 5 from Schwartz and Schwartz Bull. 11. Cornell Univ., Ithaca, New York. (1981). Halls, L. K. 1978. White-tailed deer. Pages 43-65 14 pp. in J. L. Schmidt and D. L. Gilbert, eds. Big Figure 2 by Charles W. Schwartz, published in game of North America: ecology and Siemer, W. F., and D. J. Decker. 1991. Human Wallmo (1978), copyrighted by the Wildlife management. Stackpole Books, Harrisburg, tolerance of wildlife damage: synthesis of Management Institute and adapted by Emily Pennsylvania. research and management implications. Oseas Routman. Human Dimensions Res. Unit, Ser. No. 91-7. Halls, L. K., Ed. 1984. White-tailed deer: ecology Dep. Nat. Resour., Cornell Univ., Ithaca, Figures 3 and 4 adapted from Burt and and management. Stackpole Books, New York. 24 pp. Grossenheider (1976) by Jill Sack Johnson. Harrisburg, Pennsylvania. 870 pp. Stapells, R. D. H. 1983. Everything you should Figures 6 through 15 are from Craven and Harris, M. T., W. L. Palmer, and J. L. George. know about electric fences and fence Hygnstrom (1993), “Controlling Deer Damage 1983. Preliminary screening of white-tailed controllers. J. C. Hallman Mfg. Co. Ltd. in Wisconsin,” University of Wisconsin deer repellents. J. Wildl. Manage. 47:516-519. Kitchaner, Ontario. 30 pp. Extension publication G3083. Hesselton, W. T., and R. A. M. Hesselton. 1982. Swihart, R. K., and M. R. Conover. 1990. White-tailed deer. Pages 878-901 in J. A. Reducing deer damage to yews and apple For Additional Chapman and G. A. Feldhamer, eds. Wild trees: testing Big Game Repellent® Ro-pel®, mammals of North America: biology, and soap as repellents. Wildl. Soc. Bull. Information management and economics. The Johns 18:156-162. Hopkins Univ. Press, Baltimore, Maryland. US Steel Corporation. 1980. How to build fences Andelt, W. F., K. P. Burnham, and J. A. Manning. Mackie, R. J., K. L. Hamlin, and D. F. Pac. 1982. with USS Max-Ten 200 high-tensile fence 1991. Relative effectiveness of repellents for Mule deer. Pages 862-877 in J. A. Chapman wire. No. T-111575 US Steel Corp. reducing mule deer damage. J. Wildl. and G. A. Feldhamer, eds. Wild mammals of Pittsburgh, Pennsylvania. 75 pp. Manage. 55:341-347. North America: biology, management and economics. The Johns Hopkins Univ. Press, Wallmo, O. C. 1978. Mule and black-tailed deer. Burt, W. H., and R. P. Grossenheider. 1976. A Baltimore, Maryland. Pages 32-42 in J. L. Schmidt and D. L. Gilbert, field guide to the mammals, 3d ed. eds. Big game of North America: ecology Houghton Mifflin Co., Boston. 289 pp. Palmer, W. L., R. G. Wingard, and J. L. George. and management. Stackpole Books, 1983. Evaluation of white-tailed deer Conover, M. R. 1984. Effectiveness of repellents Harrisburg, Pennsylvania. repellents. Wildl. Soc. Bull. 11:164-166. in reducing deer damage in nurseries. Wildl. Soc. Bull. 12:399-404. Pomerantz, G. A., C. Ng, and D. J. Decker. 1986. Summary of research on human tolerance of Cummings, M. W., M. H. Kimball, and W. M. Editors wildlife damage. Nat. Resour. Res. Ext. Ser. Longhurst. 1980. Deer-resistant plants for Scott E. Hygnstrom No. 25. Dep. Nat. Resour., Cornell Univ., ornamental use. Leaflet 2167. Div. Agric. Robert M. Timm Ithaca, New York. 42 pp. Sci., Univ. California. Oakland. 7 pp. Gary E. Larson Fargione, M. J., P. D. Curtis, and M. E. Richmond. 1991. Resistance of woody ornamental plants to deer damage. Cornell Coop. Ext. Fact Sheet. Ithaca, NY. 4 pp.

D-40 David S. deCalesta Research Wildlife Biologist Northeastern Forest Experiment ELK Station USDA Forest Service Warren, Pennsylvania 16365

Gary W. Witmer Research Wildlife Biologist Denver Wildlife Research Center USDA-APHIS-ADC Department of Natural Resource Sciences Washington State University Pullman, Washington 99164-6410

Fig. 1. Rocky Mountain elk, Cervus elaphus nelsoni

Damage Prevention and Cultural Methods Repellents Control Methods Alternative forage plants provide Moderately effective for short periods protection under limited conditions. (2 to 4 weeks). They usually require Exclusion multiple applications. Planting larger trees, especially conifers, is highly successful. Toxicants Large wooden panels around haystacks are effective but Alternating grazing by cattle and elk None are registered. expensive. Wrapping haystacks provides increased amounts of with plastic sheeting or netting is nutritious forage for both on the Trapping less expensive but effective for only same pasture. Corral-type traps are cumbersome, 1 to 2 years. Tensar snow fence Harvesting timber in large blocks (100 expensive to erect, and of limited material is inexpensive and effective to 200 acres [40 to 80 ha]) promotes effectiveness. for many years. increased forage production and Woven-wire fencing is highly effective, overwhelms elk with more forage Shooting but expensive. Electric fencing is than they can eat, increasing Special hunts designed to reduce local less expensive and almost as potential for adequate seedling elk numbers are of limited effective as woven wire. density. effectiveness.

Welded-wire cages up to 6 feet (1.8 m) Frightening Selective harvest of individual tall effectively prevent elk damage offending elk may provide relief to fruit and ornamental trees. Hazing with aircraft provides short- from localized damage. term and expensive control of Vexar® and Tubex® plastic cylinders damage to range and forage crops. and paper budcaps effectively Other Methods prevent elk damage to conifer and Propane exploders provide temporary Some western states compensate hardwood seedings. (2 to 4 weeks) relief from elk damage. landowners for damage by elk to agricultural crops.

Identification Roosevelt elk (C. e. roosevelti) is the in- shelter of dense stands of conifer and land coastal areas of northern Califor- deciduous trees for protection from The elk is a large, powerful animal nia, Oregon, Washington, Vancouver temperature extremes, predation, and with an adult weight averaging over Island, British Columbia, and Afognak harassment by humans. Elk usually 400 pounds (180 kg) (Fig. 1). Pelage Island, Alaska. The Tule elk (C. e. spend their summers at higher, cooler (hair coat) is light to dark reddish nannodes) is found only in California elevations. In fall, they migrate along brown on the body, a darker brown on and the Manitoban elk (C. e. manito- traditional corridors (2 to 80 miles [3 to the neck and legs, and creamy on the bensis) is found in Manitoba and 133 km]) long to lower elevations to large rump patch. Males bear large, Saskatchewan. escape weather extremes and snow impressive antlers with six or more depths that prohibit foraging in winter. tines branching from two heavy cen- Habitat Some herds are not migratory, spend- tral beams. ing the entire year within fairly well- defined and restricted areas. Although elk once roamed freely into Range lower elevation grasslands, they are now found primarily close to heavily Food Habits The Rocky Mountain elk (Cervus forested areas that are dotted with elaphus nelsoni) is found in the Rocky natural or human-made (clear-cut) Elk graze on grasses and forbs, and Mountain states and in scattered loca- openings. Typically, elk use the open- browse on shrubs, tree seedlings, and tions in the Midwest and East (Fig. 2). ings to forage for food. Elk seek the saplings. Diet is variable, depending The current distribution of the on the availability and nutritive con-

D-42 tent of forages. Elk dietary preferences Damage often overlap those of domestic and other wild ungulates. Where both Elk commonly impact agricultural grasses and shrubs are available, elk resources by competing with domestic may favor grasses. When snow livestock for pasture and damaging reaches sufficient depth to cover cereal and hay crops, ornamental grasses and shrubs, elk are forced to plants, orchards, and livestock fences. rely on conifer seedlings and saplings, Elk also damage forest resources by and bark and twigs of deciduous trees, feeding on seedlings and saplings of such as aspen. Wind-fallen branches coniferous and deciduous trees. Dur- and attached arboreal lichens are an ing winter, elk concentrate in areas important energy source in winter. where food is available, including pastures, winter wheat fields, and young General Biology, conifer plantations. A survey conduct- Reproduction, and ed in 1989 indicated that elk caused damage to crops in seven states, Behavior mostly to haystacks and pastures. Elk damage appears to be a local problem Weather and human activities influ- that usually is dealt with locally. ence elk activity. Where no hunting is Fig. 3. Elk browsing results in a ragged twig allowed, elk readily habituate to hu- Elk damage problems are increasing in edge. mans and may be observed foraging property developed in traditional elk during daylight hours. Otherwise, elk wintering ranges. This problem can be tend to forage primarily in the early avoided by zoning regulations that morning hours, in late afternoon, and prohibit development in such areas. during the night. They also forage Because the elk is a highly desired more on warmer south-facing slopes game animal, management efforts in during daylight hours in colder the last few decades have concentrated months, retiring to the thick protective on increasing the size of local elk cover of conifer/deciduous forests in herds. As elk numbers have gradually early afternoon. In summer, elk forage increased in many parts of their range, early in the day when temperatures the incidence and intensity of damage are lower and seek refuge from mid- to agriculture and forestry have also day heat and insects in cooler riparian increased. areas or forested, windswept ridge tops. Damage Identification Elk use a variety of habitats and habitat components (slope, aspect) to opti- Plants browsed by elk have a charac- mize feeding opportunities, thermal teristic appearance. Vegetation is regulation, and protection from preda- grasped between the lower incisors tion. This flexibility is closely associ- and the upper palate and ripped or Fig. 4. Rabbit browsing results in twigs and o ated with the impact elk have on torn, resulting in splintered and frag- small branches cut cleanly at a 45 angle. domestic hay, grain crops, and on pas- mented plant parts (Fig. 3). In contrast, tures shared with domestic livestock. rabbits and large rodents clip vegeta- Elk tend to roam over greater expanses o For example, spring migration coin- tion off at a sharp 45 angle (Fig. 4). Elk of habitat than deer, so the occurrence cides with the development of new damage to conifer seedlings may of damage by elk is more widespread growth of succulents, which concen- appear as a thorough stripping of bark and sporadic than damage by deer. trates feeding in pastures and grain from the upper half of the growing tip Also, because elk move in groups in- crops and leads to heightened levels of or “lateral” (Fig. 5). This damage gen- stead of singly, the nature of their de- damage. erally occurs weeks after planting, usu- struction to crops and pastures ally in early to midspring. Meadow includes trampling, much like that of The breeding season (rut) begins in mice gnaw or “girdle” rather than clip domestic livestock. late summer, when dominant males as larger rodents and rabbits do, or (bulls) herd “harems” of cows together browse as elk and deer do. The Damage by elk is often seasonal. Dam- for breeding. Cow elk may breed as appearance of damage to browsed age to hay and grain crops generally yearlings, but many breed first as plants is similar for elk, deer, and occurs in spring when these crops are 2-year-olds. A single calf is born about cattle, but their tracks and scats (drop- the first succulent vegetation to 250 days following conception. pings) are easily distinguished (Fig. 6). emerge, and native forages are in short

D-43 5" 4 1/2" 3"

Deer Elk Cattle Fig. 6. Tracks of deer, elk, and cattle

supply. If native forages are chroni- where they are sufficiently abundant. cally limited, damage to crops may Elk are completely protected in most persist through harvest. Much of the areas with small populations. damage to orchards occurs in winter and late spring when the growing tips of young (1- to 5-year-old) trees are Damage Prevention and high in protein and highly digestible. Control Methods Damage may continue through late summer at a reduced level. Conifers In some situations, only one technique are often damaged after they are for controlling elk damage is neces- planted on clear-cut sites. Elk are sary. In many situations, however, the drawn to conifers when other food greatest reduction and prevention of supplies are limited and/or of low nu- future damage will be accomplished tritive quality. Elk also are attracted by application of more than one during spring when conifers produce damage control technique. new growth that is especially palatable and highly digestible. Damage to hay- Exclusion stacks occurs during winter when Fencing has provided relief from elk there is little food available for elk on damage where plants cannot be pro- winter ranges. Elk damage to pastures tected individually, such as in hay and usually occurs during winter and dur- grain fields, large orchards, and pas- ing migration periods when elk move tures. Six-foot-high (1.8-m) woven- between summer and winter ranges. wire fences, topped with two strands Elk usually damage areas that border of smooth or barbed wire (Fig. 7) will standing timber because they have prevent access, but the cost is high learned from their association with hu- (Table 1). Some states have cost-share mans not to venture far out into large programs wherein some or all of the openings. They also prefer riparian cost of fencing materials may be borne zones and benches as opposed to steep by one or more agencies responsible slopes, and damage is usually distrib- for managing elk damage. uted accordingly. Much of the damage Recently, high-voltage (3,500- to 7,500- caused by elk is in response to low volt) electric fences have proven to be availability of forage on winter range; a relatively inexpensive and effective thus crops on winter range or along alternative to woven-wire fences. They migration routes are often damaged. feature 8 to 11 smooth strands of triple-galvanized, high-tensile steel Legal Status wire supported by conventional fence post systems (Fig. 8). Considerable expertise is required to construct these Fig. 5. Conifer seedling damaged by elk shortly Elk are protected and classified as a after planting. game animal in states and provinces fences, but when built properly, they

D-44 Barbed wire can provide nearly as much protection 15' 4" above from damage as mesh fences. woven wire Researchers in Pennsylvania 6" developed 4- to 5-strand electric fences 6" (Fig. 9) that provided 80% or more protection from deer damage. In Oregon, an 8-foot (2.5-m) electric fence consisting of 11 wires successfully kept 78" elk from entering a rhododendron nursery that previously had sustained persistent trampling damage. A key component of electric fences is the high-voltage charger or “energizer.” These are available as 110 volt or battery-operated units.

Fig. 7. Woven-wire fences can exclude elk. For a fence to be effective, it must be seen by elk. In the case of an electric fence, which a herd can easily run through, it must be seen and associated with an electric shock. Place branches along the top of livestock fences and drape light-colored sur- veyor tape from electric fences to make them more visible to elk. To help “initiate” elk to the shocking power of fences, place peanut butter on tinfoil strips and attach the strips to electric fence wires 3 feet (1 m) above ground . For more details on fencing, see the Deer chapter in this book. Haystacks have traditionally been protected by wooden panels (Fig. 10). Because panels are expensive to build and unwieldy to place in position, they are no longer recommended except in cases where nothing else is available. With the advent of the effective and less expensive electric fencing, it is now feasible to place perimeter fences around hay yards. They allow ranchers easier access to hay and greater + mobility in moving the hay within 12" - yards. Electric fences such as those 12" + illustrated are permanent installations, 12" - lacking the mobility of panel fencing, 12" + 10" - so placement is a factor in choosing 10" + panels or electric fences. 8" - 8" + 6" - Haystacks can be protected from elk 6" + for one or two seasons by wrapping plastic barriers around them. Ten-foot- Fig. 8. A high-tensile electric fence can exclude elk. wide (3-m) sheets of 6-mil black plastic (Visqueen®) or netting made of expanded polyethylene are commonly used. Attach the sheets to standing stacks of hay bales by tying baling twine around pebbles enclosed in a

D-45 Two-wire sleeves fold of plastic at the top of the sheet, and tying the loose end of the twine to Batten post + baling twine on hay bales (Fig. 11). The netting is simply stretched around hay 24" stacks. The Tensar® snow fence, which comes 20' - in 8 x 100-foot (2.6 x 30-m) rolls and has a 30-year life span, can also be 18" wrapped around haystacks. State and + federal wildlife agencies have been purchasing it and loaning it to ranch- 18" - ers to use before winter elk damage begins. 12" + For smaller orchards (fewer than 50 6" trees), protect individual trees with 8" Trip wire 6-foot (1.8-m) cylinders of welded wire (Fig. 12). 8" Ground level 5' Protectors for individual coniferous and deciduous tree seedlings are effective until the leader (growing tip) or lateral branches grow out of the protectors and are once again exposed to elk browsing. Use rigid diamond- Fig. 9. The Penn State electric fence may be of use in excluding elk as well as deer. pattern plastic or nylon tubes (Vexar®), netting, and waterproof paper cylinders (bud caps) (Fig. 13) to protect conifer seedlings. Vexar® tubes extend from ground level to above the top of the seedling. Netting and bud caps fit over the growing tips of the leader stem and lateral branches. Vexar® tubes are more expensive than netting and bud caps but have a longer life span (about 5 years). Tubex® tree shelters (Fig. 14) are trans- lucent, solid-walled cylinders 5 to 6 Fig. 10. Wooden panels have been used to protect haystacks. feet (1.5 to 1.8 m) tall, and 5 to 6 inches (12 to 15 cm) in diameter. The cylinders create a mini-greenhouse that accelerates the growth of seedlings. At $3.25 each, Tubex® protectors are expensive. Vexar® protectors, netting, and bud caps are recommended for conifer seedlings, while Tubex® is recommended for deciduous tree seedlings. Vexar® and Tubex® protectors must be held upright by lashing them to stakes driven into the ground. Both protectors are designed to biodegrade in about 5 years. If support stakes are wooden, they must be treated to prevent rot or they will break off at Fig. 11. Black plastic sheeting or netting wrapped around hay stacks provides inexpensive and ground level in 1 to 2 years. effective protection for 1 to 2 seasons. Elk can be excluded from tree regeneration sites by dense slash left after

D-46 harvest. Unfortunately, when slash is sufficiently thick to deny elk access to seedlings, it provides protective cover for rodents. Subsequent increases in rodent populations could result in severe rodent damage to seedlings. Usually there is insufficient slash to 6' provide total coverage on sites. Protec- tion is provided to a limited number of seedlings in places where the slash is sufficiently dense.

Cultural Methods Under limited circumstances, elk may be “deferred” from damaging crops by planting other forages that elk prefer. Broadcast legumes and domestic annual and perennial grasses over regeneration sites before planting coni- Fig. 12. A cylinder of welded wire can protect an individual fer seedlings. Grasses and legumes tree from elk damage. that are not sufficiently cropped by elk, however, will provide excellent vole habitat, and damage by these rodents to seedlings may become a problem. Graze sheep in summer on such sites to remove excess forage until elk begin to graze in fall and winter.

Fig. 14. Tubex® tree shelters are a new individual Fig. 13. Vexar® tubes (left), or netting (middle) can protect seed- seedling protector designed for deciduous tree lings. Bud caps (right) have also been used successfully. seedlings.

D-47 Food plots and salt blocks have been a 10-year period, all timber harvests Frightening (Hazing) used on public lands adjacent to agri- are conducted within 1 to 2 years and Propane exploders (Fig. 15) can pre- cultural fields and pastures to reduce the area is not cut again for 10 years. vent elk from using sites for several damage by resident and migratory elk. This system may work in other areas weeks, after which the elk lose interest Food plots are maintained in an early where elk are causing significant dam- and go elsewhere. Generally, one successional state (grasses and forbs) age to seedlings. Placing the cuts in exploder will protect 5 to 10 acres (2 to by one or more techniques: seeding, adjoining blocks (“progressive” clear- 4 ha). Several may be required for mowing, fertilizing, burning, and/or cutting) rather than scattering them larger areas. Exploders are most effec- spraying with herbicides. Effectiveness will also reduce the amount of forest tive when their locations are changed of this approach is still undergoing fragmentation, which is an emerging every few days so that elk do not ha- evaluation. The expense of establishing concern in forest management. bituate to the sound pattern. Exploders and maintaining substantial acreages Where elk and livestock compete for may be an unacceptable nuisance to of high-quality food plots limits their the same forage, a long-term solution nearby neighbors. use. is a system of successional cropping. If Elk may be temporarily hazed or Planting taller seedlings can reduce elk cattle placed on the pasture from late frightened out of crop fields, orchards, damage. Most seedlings are about 18 spring through late summer do not and pastures by the use of fixed-wing inches (46 cm) tall. Seedlings 36 inches remove all the forage, it will recover, aircraft or helicopters, but both are (90 cm) or taller will provide more mature in early fall, and provide quan- expensive. Elk will return, however, browse than elk can crop, and with tities of high quality forage for elk in especially if pastures are on their tradi- their greater potential for rapid growth winter. The elk, in turn, will crop and tional winter range. these seedlings can grow out of the stimulate the forage, providing good reach of elk faster. forage for cattle returning to the pas- Repellents ture in spring. Such a system has The early release of seedlings may also increased the availability of forage and Repellents may reduce elk damage in be achieved by eliminating other numbers of both livestock and elk. orchards, vineyards, and conifer plan- vegetation. Studies in western Oregon Careful planning is required to ensure tations. Where frequent washing rains demonstrated that using herbicides to that proper numbers of livestock and occur, some repellents must be applied eliminate competing vegetation elk use the pasture. Special hunts may more than once. Damage can be pre- allowed conifer seedlings to grow suf- be required to ensure that excessive vented without treating the entire area ficiently fast that they outgrew the numbers of elk do not occur. by applying odor repellents to plants browsing of deer and elk. Elk, like deer, are attracted to the edge habitat between openings and forested areas. Their use of openings begins to decline 200 feet (60 m) into openings; by 400 to 600 feet (120 to 180 m), use drops below 50%. Creating larger openings by clear-cutting larger acreages (100 to 200 acres [40 to 80 ha]) as opposed to the 40 to 50 acres (16 to 20 ha) currently practiced on public lands will decrease elk damage in the interior portions of such clear-cuts. Protecting seedlings on the perimeters of larger clear-cuts with repellents or seedling protectors will provide an integrated protection system. Recent studies with deer in the East suggest that concentrating projected timber harvest into a shortened period of time will overwhelm deer with a surplus of food, reducing the level of damage to seedlings. Instead of spreading out projected harvests over Fig. 15. Propane exploders may be useful in scaring elk away from particular areas.

D-48 within a 25-foot-wide (10-m) strip Elk-reduction hunts are sensitive man- Compensation around field edges where most of the agement issues. The general hunting Four states pay ranchers directly for damage occurs. public has had difficulty understand- crop damage caused by elk. Funding ing why there is a need to remove The US Forest Service has a “20 to 80 for claims (which have a low upper individual elk, or to reduce popula- percent” rule for determining whether limit, usually under $5,000) is taken tions when only a limited number of repellents will be successful: If elk from license fees and tags that hunters licenses is available to hunt for bulls. damage to conifers is less than 20%, pay to hunt elk and other game. Com- Effective public relations programs are application of the repellent will not pensation may be temporarily satisfac- essential for acceptance of and support pay for itself. If the damage is over tory to ranchers and farmers, but it for population reduction. 80%, the elk have become too habitu- does nothing to alter the circumstances ated to feeding in the area and will Special hunts may provide temporary favoring damage, so the damage will not be deterred by the application of relief from damage, but the conditions continue and may even increase. Com- repellents. conducive to damage remain. Once the pensation should be considered as a population rebuilds, damage is likely temporary, stop-gap response requir- Little success is reported with repel- to resume, especially in orchards, crop ing a better, permanent solution. lents such as human hair, tankage, fields, and pastures. Protection of coni- blood meal, or thiram. Successful Compensation is not a particularly fer seedlings by hunting to reduce repellents include formulations of fer- efficient use of funds for reimbursing local elk densities is an exception. mented eggs (Big Game Repellent® or individuals with damage. In Colo- Seedlings can attain a height sufficient Deer-Away®) and hot sauce contain- rado’s $1.5 million program, only to avoid elk damage within 3 to 5 ing capsaicin. For additional informa- $300,000 was spent in actual reim- years, which is well within the period tion on repellents, see the Pesticides bursement to persons with losses. of protection afforded by a series of and Supplies and Materials sections Approximately $350,000 went to successful special hunts. in this book. administration expenses, and $800,000 Another form of population reduction to provide damage prevention Population Reduction is the translocation of problem ani- materials. Permits are issued (usually for mals. Capturing and translocating elk antlerless elk) to reduce local elk popu- was a common procedure in several states as long as there were areas Economics of Damage lations to levels of damage that are ac- and Control ceptable. These reductions generally understocked with elk. Small numbers are of two kinds: local herd reduction, of elk (1 to 10) were captured in large, Before any control program is begun, and problem-animal elimination. In baited corral traps. Free-ranging indi- determine whether the cost of control the former, the herd is usually too vidual elk were immobilized by drugs will exceed the costs of damage. The large for local resources and a general injected by projectiles fired from rifles. costs of control methods vary greatly reduction in population density is These programs are being phased out (Table 1). required. Special elk damage hunts are because states with sufficient elk to cause damage problems no longer established to reduce the size of herds Cost-effectiveness of damage control have areas of too few elk. Costs of on public lands, and, in some cases, on efforts may be approximated by divid- trapping and transporting elk are pro- private property. Such hunts are con- ing the value of elk damage by the cost hibitive and are not recommended ducted as extra seasons for which of control. The result is usually re- unless outside financial assistance can hunters enter drawings. Hunters must ferred to as the benefit-cost ratio. If the be obtained. have good access to areas for these ratio is less than 1.0, control is costing hunts to be effective for herd reduction A final potential population reduction more than damage and is not justifi- and/or problem-animal elimination. technique is the use of reproductive able. More sophisticated benefit-cost models that will allow projection of The second kind of reduction is for inhibitors. Effective reproductive benefits and costs into the future have individual landowners who experience inhibitors exist for elk. Unfortunately, yet to be developed for elk. unacceptable losses of crops to one or there is no effective, selective delivery a few elk. Permits are issued to the in- system available to implant or inject dividual landowner to eliminate these the inhibitors into the bodies of free- problem animals; hunters usually are ranging elk. not used to harvest the elk.

D-49 Table 1. Costs of methods for controlling elk damage. Duration of Method Costa protection Woven wire fence $2/foot 30 years Electric fence $1/foot 40 years Panel fence $3.50/foot 40 years Repellent highly variable weeks Wire cylinders for fruit trees $4 to $6/tree 5 to 10 years Alternate forage $130/acre 5 years Herbicide use $30 to $40/acre life of tree Plant larger trees $100 to $200/acre life of tree Plastic/paper cylinders $200 to $350/acre 5 years for conifers (rigid mesh) $150 to $300/acre 3 years (flexible mesh) $75/acre 1 to 2 years (paper bud cups) Tree shelters $3.25/tree 5 years for deciduous trees Hazing by aircraft $200+/hour weeks Exploders $10/acre 3 to 5 weeks Trap & relocate highly variable Special hunts highly variable Visqueen® $0.50/foot 1 year Netting $0.65/foot 1 to 2 years Tensar® snow fence $1/foot 30 years

aCosts are for materials only and vary from site to site. Labor costs are not included.

Acknowledgments Byrne, A. E. 1989. Experimental applications of Schneidmiller, J. F. 1988. Fencing methods to high-tensile wire and other fencing to control control big game damage to stored crops in big game damage in northwest Colorado. Wyoming. Proc. Great Plains Wildl. Damage We thank the following individuals for provid- Proc. Great Plains Wildl. Damage Control Control Workshop. 8:217-221. ing pertinent information: H. C. Black, G. E. Workshop. 9:109-115. Burgoyne, J. E. Gillespie, M. Shaw, V. T. Thomas, J. W., and D.E. Toweill, eds. 1982. Elk Supplee, and D. E. Toweill. Campbell, D. L., and J. Evans. 1978. Establishing of North America: ecology and management. native forbs to reduce black-tailed deer Stackpole Books, Harrisburg, Pennsylvania. Figure 1 from Schwartz and Schwartz (1981). browsing damage to Douglas-fir. Proc. 698 pp. Verteb. Pest Conf. 8:145-151. Figure 2 adapted from Thomas and Toweill United States Steel. 1980. How to build fences (1982) by L. Bryant and C. Maser. Long, W. M. 1989. Habitat manipulations to with USS Max-10 200 high-tensile fence prevent elk damage to private rangelands. wire. United States Steel, Pittsburgh, Figures 3, 4, and 7 through 15 by Jill Sack John- Proc. Great Plains Wildl. Damage Control Pennsylvania. 75 pp. son. Workshop. 9:101-103. Witmer, G. W., and R. Cogan. 1989. Elk and crop Figures 5 and 6 by the authors. Peek, J. M. 1982. Elk. Pages 851-861 in J. A. damage in Pennsylvania. Proc. Eastern Chapman and G. A. Feldhamer, eds. Wild Wildl. Damage Control Conf. 4:220-224. mammals of North America: biology, For Additional management, and economics. The Johns Information Hopkins Univ. Press. Baltimore, Maryland. Rochelle, J. A. 1992. Deer and elk. Pages 333-350 Editors in H. C. Black, ed. Silvicultural approaches to Andelt, W. F., D. L. Baker, and K. P. Burnham. Scott E. Hygnstrom animal damage management in Pacific 1991. Relative preference of captive cow elk Robert M. Timm Northwest forests. US Dep. Agric. For. Serv. for repellent-treated diets. J. Wildl. Manage. Gary E. Larson 56:164-173. Tech. Rep. PNW-GTR-287. Portland, Oregon. Anderson, E. W., and R. J. Scherzinger. 1975. Improving quality of winter forage for elk by cattle grazing. J. Range Manage. 28:120-125.

D-50 F. Robert Henderson Extension Specialist Animal Damage Control MOLES Kansas State University Manhattan, Kansas 66506-1600

Fig. 1. Eastern mole, Scalopus aquaticus

Damage Prevention and Frightening Trapping (most effective control method) Control Methods Ineffective. Out O’ Sight® Trap. Repellents Exclusion Bayonet trap or harpoon trap (Victor® None are registered. Generally not practical, except in very Mole Trap). Toxicants small, high-value areas where an Nash® (choker-type) mole trap. aboveground and underground Strychnine alkaloid. barrier (sheet metal, brick, wood) Easy-set mole eliminator. Chlorophacinone is registered in some might restrict moles. Cinch mole trap. states. Cultural Methods Fumigants Death-Klutch gopher trap. Packing the soil destroys burrows, and Shooting sometimes moles if done in early Aluminum phosphide. Not practical. morning or late evening. Gas cartridges. Reduction in soil moisture and food Other Methods source removal by the use of insecti- None tested have proven effective. cides discourages moles and generally results in lower populations.

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 D-51 Great Plains Agricultural Council Wildlife Committee Identification gopher. Three to five moles per acre (7 to 12 per ha) is considered a high Yates and Pedersen (1982) list seven population for most areas in the Great North American species of moles. Plains. They are the eastern mole (Scalopus Deep runways lead from the mole’s aquaticus), hairy-tailed mole den to its hunting grounds. The den- (Parascalops breweri), star-nosed mole ning area proper consists of irregular (Condylura cristata), broad-footed mole chambers here and there connected (Scapanus latimanus), Townsend’s mole with the deep runways. The runways (Scapanus townsendii), coast mole follow a course from 5 to 8 inches (12.7 (Scapanus orarius), and shrew mole to 20.3 cm) beneath the surface of the (Neurotrichus gibbsii). ground. The chambers from which The mole discussed here is usually these runs radiate are about the size of referred to as the eastern mole Fig. 2. Range of the eastern mole in North a quart jar. America. (Scalopus aquaticus). It is an insectivore, Most of a mole’s runway system is not a rodent, and is related to shrews made up of shallow tunnels ranging and bats. is the most common and its range is over its hunting ground. These tunnels shown in figure 2. The star-nosed mole True moles may be distinguished from may not be used again or they may be is most common in northeastern meadow mice (voles), shrews, or re-traversed at irregular intervals. United States and southeastern pocket gophers—with which they are Eventually, they become filled by the Canada, sharing much of the same often confused—by noting certain settling soil, especially after heavy range as the hairy-tailed mole. The characteristics. They have a hairless, showers. In some cases, moles push remaining four species are found west pointed snout extending nearly 1/2 soil they have excavated from their of the Rocky Mountains. The inch (1.3 cm) in front of the mouth deep runways into the shallow tun- Townsend mole and the coast mole are opening. The small eyes and the open- nels. These subterranean hunting paths distributed in the extreme northwest ing of the ear canal are concealed in are about 1 1/4 to 1 1/2 inches (3.2 to corner of the United States and south- the fur; there are no external ears. The 3.8 cm) in diameter. Moles usually west Canada. The broad-footed mole forefeet are very large and broad, with ridge up the surface of the soil, so their is found in southern Oregon and palms wider than they are long. The tunnels can be readily followed. In wet throughout the coastal region of Cali- toes are webbed to the base of the weather, runways are very shallow; fornia excluding the Baja peninsula. claws, which are broad and depressed. during a dry period they range some- Finally, the shrew mole is also found The hind feet are small and narrow, what deeper, following the course of along the West Coast from Santa Cruz with slender, sharp claws. earthworms. County, California, to southern British Columbia (Yates and Pedersen 1982). Moles make their home burrows in Average Dimensions and Weight high, dry spots, but they prefer to hunt in soil that is shaded, cool, moist, and Males : Habitat populated by worms and grubs. This Average total length, 7 inches (17.6 cm) preference accounts for the mole’s Average length of tail, 1 1/4 inches The mole lives in the seclusion of un- attraction to lawns and parks. In (3.3 cm) derground burrows, coming to the neglected orchards and natural wood- Average weight, 4 ounces (115 g) surface only rarely, and then often by lands, moles work undisturbed. The accident. Researchers believe that the ground can be infiltrated with run- Females: mole is a loner. On several occasions ways. Moles commonly make their Average total length, 6 5/8 inches two or even three moles have been denning areas under portions of large (16.8 cm) trapped at the same spot, but that does trees, buildings, or sidewalks. not necessarily mean they had been Average length of tail, 1 1/4 inches The maze of passages that thread the living together in a particular burrow. (3.3 cm) soil provides protective cover and Networks of runways made indepen- Average weight, 3 ounces (85 g) traffic for several species of small dently occasionally join otherwise mammals. Voles (meadow mice), separate burrows. Range white-footed mice, and house mice live Because of their food requirements, in and move through mole runways, Out of the seven species that occur in moles must cover a larger amount of helping themselves to grains, seeds, North America, three inhabit lands area than do most animals that live and tubers. The mole, however, often east of the Rocky Mountains (Yates underground. The home range of a gets blamed for damaging these and Pedersen 1982). The eastern mole male mole is thought to be almost 20 plants. Moles “swim” through soil, times that of a male plains pocket often near the ground surface, in their

D-52 search for worms, insects, and other foods. In doing so, they may damage plants by disrupting their roots (Fig. 3).

Food Habits

The teeth of a mole (see Fig. 1) indicate the characteristics of its food and general behavior. In several respects moles are much more closely related to car- nivorous or flesh-eating mammals than to rodents. The mole’s diet consists mainly of the insects, grubs, and worms it finds in the soil (Table 1). Moles are thought to damage roots and tubers by feeding on them, but rodents usually are to blame. Moles eat from 70% to 100% of their weight each day. A mole’s appetite seems to be insatiable. Experiments with captive moles show that they will Fig. 3. Moles “swim” through soil, often near the usually eat voraciously as long as they ground surface, in their search for worms, are supplied with food to their liking. insects, and other foods. In doing so, they may The tremendous amount of energy damage plants by disrupting their roots. expended in plowing through soil requires a correspondingly large amount of food to supply that energy. General Biology, Damage and Damage Moles must have this food at frequent Reproduction, and Identification intervals. Behavior Moles remove many damaging Moles prefer loose, moist soil abound- insects and grubs from lawns and Table 1. Stomach contents of 100 gardens. However, their burrowing eastern moles: ing in grubs and earthworms. They are most commonly found in fields and habits disfigure lawns and parks, woods shaded by vegetation, and are destroy flower beds, tear up the Food item Number roots of grasses, and create havoc in of stomachs not able to maintain existence in hard, compact, semiarid soil. small garden plots. White grubs 64 The mole is not a social animal. Moles It is important to properly identify Earthworms 49 the kind of animal causing damage Beetles 67 do not hibernate but are more or less active at all seasons of the year. They before setting out to control the dam- Beetle larvae 44 age. Moles and pocket gophers are Other larvae 25 are busiest finding and storing foods during rainy periods in summer. often found in the same location and Centipedes 25 their damage is often confused. Ants 19 The gestation period of moles is Control methods differ for the two Wasps 7 approximately 42 days. Three to five species. Flies 2 young are born, mainly in March and Plant fibers and rootlets 2 early April. Moles leave volcano-shaped hills Seed pods or husks 43 (Fig. 4a) that are often made up of Crickets 10 The moles have only a few natural clods of soil. The mole hills are Insect fragments 31 enemies because of their secluded life pushed up from the deep tunnels Puparia 21 underground. Coyotes, dogs, badgers, and may be 2 to 24 inches (5 to 60 Cocoons 10 and skunks dig out a few of them, and cm) tall. The number of mole hills is Spiders 23 occasionally a cat, hawk, or owl sur- not a measure of the number of Grasshoppers 2 prises one above ground. Spring moles in a given area. Surface tun- Bugs 3 floods are probably the greatest dan- nels (Fig. 4b) or ridges are indicative Skin of grain or roots 3 ger facing adult moles and their of mole activity. Hairworm 1 young.

D-53 Pocket gopher mounds are generally Fig. 4. Mole sign kidney-shaped and made of finely sifted and cloddy soil (Fig. 4c). Gener- ally, gophers leave larger mounds than moles do. Gopher mounds are often built in a line, indicative of a deeper tunnel system.

Legal Status

Moles are unprotected in most states. See state and local laws for types of traps, toxicants, and other methods of damage control that can be used.

Damage Prevention and Fig. 4a. Moles push dirt through vertical tunnels onto surface of ground. Control Methods

Exclusion For small areas, such as seed beds, install a 24-inch (61-cm) roll sheet metal or hardware cloth fence. Place the fence at the ground surface and Mole hill bury it to a depth of at least 12 inches (30 cm), bent out at a 90o angle (Fig. 5). Fig. 4b. Ridge caused by tunneling of mole under sod. Cultural Methods Plug In practice, packing the soil with a roller or reducing soil moisture may reduce a habitat’s attractiveness to moles. Packing may even kill moles if done in the early morning or late evening. Milky-spore disease is a satisfactory natural control for certain white grubs, Plug one of the mole’s major food sources. It may take several years, however, for the milky-spore disease to become established. Treatments are most effective when they are made on a commu- Gopher mound Mole tunnel and hill nity-wide basis. The spore dust can be Fig. 4c. Comparison of gopher mound and mole hill. applied at a rate of 2 pounds per acre (2.3 kg/ha) and in spots 5 to 10 feet (1.5 to 3m) apart (1 level teaspoon [4 g] per spot). If you wish to try discouraging moles by beginning a control program for white grubs, contact your local extension agent for recommended procedures. Because moles feed largely on insects and worms, the use of certain insecticides may reduce their food supply, causing them to leave the area. How- ever, before doing so, they may Fig. 5. Mole fence

D-54 increase their digging in search of course owners, however, report that brand names of the more common food, possibly increasing damage to moles can be repelled from surface traps are: Victor® mole trap, Out O’ turf or garden areas. Check local tunnels by placing aluminum phos- Sight®, and Nash® (choker loop) mole sources of insecticides for controlling phide pellets in them. Since state pesti- trap (Fig. 6). The Victor® trap has grubs. Follow the label instructions for cide registrations vary, check with sharp spikes that impale the mole use. your local extension or USDA-APHIS- when the spikes are driven into the ADC office for information on toxi- ground by the spring. The Out O’ Frightening cants and repellents that are legal in Sight® trap has scissorlike jaws that Some electronic, magnetic, and vibra- your area. Care should be taken when close firmly across the runway, one tional devices have been promoted as using chemicals. Read and follow label pair on either side of the trigger pan. being effective in frightening or repel- instructions when using toxicants and The Nash® trap has a choker loop that ling moles. None, however, have been fumigants. tightens around the mole’s body. proven effective. Others include the Easy-Set mole Trapping eliminator, Cinch mole trap, and the Repellents Trapping is the most successful and Death-Klutch gopher trap. No chemical products are registered or practical method of getting rid of These traps are well suited to moles effective for repelling moles. Borders moles. There are several mole traps on because the mole springs them when of marigolds may repel moles from the market. Each, if properly handled, following its natural instinct to reopen gardens, although this method has not will give good results. The traps are set obstructed passageways. been scientifically tested. over a depressed portion of the surface tunnel. As a mole moves through the Success or failure in the use of these devices depends largely on the Toxicants tunnel, it pushes upward on the depressed tunnel roof and trips the operator’s knowledge of the mole’s Since moles normally do not consume broad trigger pan of the trap. The habits and of the trap mechanism. grain, toxic grain baits are seldom effective. Two poisons are federally registered for use against moles. Ready-to-use grain baits containing strychnine are sold at nurseries or a garden supply stores. Recent work by Elshoff and Dudderar at Michigan State University reported on the use of Orco Mole Bait, a chlorophacinone pellet which is used in Washington and some other states under 24(c) permits for mole damage control. Even though the researchers stated the use of this toxicant is a b highly effective and easily applied mole control technique, there are dis- advantages. Two or more successive treatments are often required. An average of 21 1/2 days was required to achieve zero damage on treated dry soil and 39 days on treated irrigated soils.

Fumigants Two fumigants, aluminum phosphide and gas cartridges, are federally registered for use against moles (see Sup- c plies and Materials). Aluminum phosphide is a Restricted Use Pesti- cide. These fumigants have the greatest effectiveness when the materials are placed in the mole’s deep burrows, not in the surface runways. Golf Fig. 6. Mole traps: (a) Out O’ Sight® (scissor-jawed), (b) Victor® (harpoon), and (c) Nash® (choker loop).

D-55 To set a trap properly, select a place in the surface runway where there is evi- Fence row dence of fresh mole activity and where Mounds the burrow runs in a straight line (Fig. 7). Dig out a portion of the burrow, locate the tunnel, and replace the soil, Fig. 7. A network of mole Deep run runways in a yard. The packing it firmly where the trigger pan arrowheads (▲) indicate good Surface ridges will rest (Fig. 8). locations to set traps. Avoid the twisting surface ridges and To set the harpoon or impaling-type do not place traps on top of trap, raise the spring, set the safety mounds. catch, and push the supporting spikes Driveway into the ground, one on either side of the runway (Fig. 9). The trigger pan should just touch the earth where the soil is packed down. Release the safety catch and allow the impaling spike to be forced down into the ground by the spring. This will allow the spike to penetrate the burrow when the trap is sprung later. Set the trap and leave it. Do not tread on or disturb any other portion of the mole’s runway. To set a scissor-jawed trap, dig out a portion of a straight surface runway, and repack it with fine soil. Set the trap and secure it by a safety hook with its jaws forced into the ground. It should straddle the runway (Fig. 10a) until the trigger pan touches the packed soil between the jaws. The points of the jaws are set about 1 inch (2.5 cm) below the mole’s runway and the trigger pan should rest on the portion as Fig. 8a. Excavation of a mole tunnel is the Fig. 8b. Replace the soil loosely in the excavation. previously described. Care should be first step in setting a mole trap. taken to see that the trap is in line with the runway so the mole will have to pass directly between the jaws. In heavy clay soils be sure to cut a path for the jaws (Fig. 10b) so they can close quickly. The jaws of this trap are rather short, so be sure the soil on the top of the mole run is low enough to bring the trap down nearer to the actual burrow. Set the triggers on both traps so that they will spring easily (Fig. 11). Remember to release the safety hook before releasing the trap. Be careful when handling these traps. To set a choker trap, use a garden trowel to make an excavation across the tunnel. Make it a little deeper than the tunnel and just the width of the trap. Note the exact direction of the tunnel from the open ends, and place the set trap so that its loop encircles this course (Fig. 12). Block the Fig. 9. Set the harpoon-type trap directly over the runway so that its supporting stakes straddle the runway and its spikes go into the runway.

D-56 Fig. 10a. Set the scissor-jawed trap so that the jaws straddle the runway. Fig. 10b. In heavy soils, make a path for the jaws to travel so they can close quickly.

excavated section with loose, damp soil from which all gravel and debris have been removed. Pack the soil firmly underneath the trigger pan with Fig. 11. Set mole trap triggers so they will spring your fingers and settle the trap so that easily. A hair-trigger setting on the scissor- the trigger rests snugly on the built-up jawed trap is shown here. soil. Finally, fill the trap hole with enough loose soil to cover the trap level with the trigger pan and to exclude all light from the mole burrow. If a trap fails to catch a mole after 2 days, it can mean the mole has changed its habits, the runway was Fig. 12. The choker loop trap is disturbed too much, the trap was set so that the loop encircles the mole’s runway. improperly set, or the trap was detected by the mole. In any event, move the trap to a new location. If one cares to take the time, moles can be caught alive. Examine tunnels early in the morning or evening where fresh burrowing operations have been noted. Quietly approach the area where the earth is being heaved up. Board Quickly strike a spade into the ridge Mole runway behind the mole and throw the animal out onto the surface. A mole occa- Cave in runway here sionally can be driven to the surface by flooding a runway system with water from a hose or ditch. Another Jar method is to bury a 3-pound (1.4-kg) coffee can or a wide-mouth quart (0.95 l) glass jar in the path of the mole Line of floor of runway and cover the top of the burrow with a board (Fig. 13).

Fig. 13. A mole can be live-captured in a pit trap. Be sure to use a board or other object to shut out all light. Cave in the runway just in front of the jar on both sides.

D-57 Other Methods Economics of Damage Acknowledgments Nearly everyone has heard of a sure- and Control fire home remedy for controlling Figures 1 and 4 from Schwartz and Schwartz (1981). moles. In theory, various materials Perhaps more problems are encoun- placed in mole tunnels cause moles to tered with moles than with any other Figures 6, 8, 9, 10, 11, 12 and 13 adapted from various sources by Jill Sack Johnson. die or at least leave the area. Such single kind of wild animal. Unfortu- cures suggest placing broken bottles, nately, people lack an appreciation of ground glass, razor blades, thorny rose the importance of moles and the diffi- For Additional branches, bleaches, various petroleum culty of gaining complete control Information products, sheep dip, household lye, where habitats are attractive to moles. chewing gum, and even human hair in Before initiating a control program for Dudderar, G. R. Moles. Univ. Michigan. Coop. the tunnel. Other remedies include Ext. Serv. Bull. E-863, 1 p. mole wheels, pop bottles, windmills, moles, be sure that they are truly out Elshoff, D. K. and G. R. Dudderar. 1989. The bleach bottles with wind vents placed of place. Moles play an important role in the management of soil and of grubs effectiveness of Orco mole bait in controlling on sticks, and similar gadgets. Though mole damage. Proc. Eastern Wildl. Damage colorful and sometimes decorative, that destroy lawns. Moles work over Control Conf. 4: 205-209. these gadgets add nothing to our the soil and subsoil. Only a part of this work is visible at the surface. Tunnel- Godfrey, G., and P. Crowcroft. 1960. The life of arsenal of effective mole control the mole. London Museum Press, 152 pp. methods. ing through soil and shifting of soil particles permits better aeration of the Henderson, F. R. 1989. Controlling nuisance moles. Coop. Ext. Serv. Kansas State Univ. Another cure-all is the so-called mole soil and subsoil, carrying humus far- C-701, Manhattan. plant or caper spurge (Euphorbia ther down and bringing the subsoil latharis). Advertisers claim that when Holbrook, H. T. and R. M. Timm. 1986. Moles nearer the surface where the elements and their control. NebGuide G86-777. Univ. planted frequently throughout the of plant food may be made available. Nebraska. Coop. Ext. Lincoln. 4 pp. lawn and flower beds, such plants supposedly act as living mole repel- Moles eat harmful lawn pests such as San Julian, G. J. 1984. Moles. Coop. Ext. Serv. white grubs. They also eat beneficial North Carolina State Univ. NCADCM No. lents. No known research supports this 134. 3 pp. claim. Castor beans are also supposed earthworms. Stomach analyses show Schwartz, C. W. and E. R. Schwartz. 1981. The to repel moles. Caution must be used, that nearly two-thirds of the moles studied had eaten white grubs. wild mammals of Missouri. rev. ed. Univ. however, since castor beans are poi- Missouri Press, Columbia. 356 pp. sonous to humans. Several electromag- If the individual mole is not out of Silver, J. and A. W. Moore. 1933. Mole control. netic devices or “repellers” have been place, consider it an asset. If a particu- US Dep. Agric., Farmers Bull. No. 1716, marketed for the control of rats, mice, lar mole or moles are where you do Washington, D.C. gophers, moles, ants, termites, and not want them, remove the moles. If Yates, T. L. and R. J. Pedersen. 1982. Moles. various other pests. Laboratory tests excellent habitat is present and nearby Pages 37-51 in J. A. Chapman and G. A. have not proven these devices to be mole populations are high, control will Feldhamer, eds. Wild mammals of North effective. Unfortunately, there are no America: biology, management, and be difficult. Often other moles will economics. The Johns Hopkins Univ. Press, short cuts or magic wands when con- move into recently vacated areas. Baltimore, Maryland. trolling moles.

Editors Scott E. Hygnstrom Robert M. Timm Gary E. Larson

D-58 Jeffrey J. Jackson Extension Wildlife Specialist Warnell School of Forest Resources OPOSSUMS University of Georgia Athens, Georgia 30602

Fig. 1. Opossum, Didelphis virginiana

Damage Prevention and Toxicants Identification Control Methods None are registered. An opossum (Didelphis virginiana) is a Fumigants Exclusion whitish or grayish mammal about the None are registered. size of a house cat (Fig. 1). Underfur is Practical where opossums are entering dense with sparse guard hairs. Its face Trapping structures. is long and pointed, its ears rounded Habitat Modification Leghold traps. and hairless. Maximum length is 40 inches (102 cm); the ratlike tail is Remove cover and plug burrows to Box traps. slightly less than half the total length. reduce frequency of visits by Cage traps. The tail may be unusually short in opossums. northern opossums due to loss by Body-gripping (kill) traps. Frightening frostbite. Opossums may weigh as Shooting much as 14 pounds (6.3 kg); males av- Generally not practical. erage 6 to 7 pounds (2.7 to 3.2 kg) and Effective where firearms are permit- Repellents females average 4 pounds (6.3 kg). The ted. Use a shotgun with No. 6 shot skull is usually 3 to 4 inches (8 to 10 or a .22-caliber rifle. None are registered. cm) long and contains 50 teeth — more than are found in any other North

Opossum tracks 6" a

Fig. 2. Opossum sign and characteristics: (a) tracks, (b) droppings, and (c) skull.

American mammal. Canine teeth General Biology, (fangs) are prominent. Tracks of both Reproduction, and front and hind feet look as if they were made by little hands with widely Behavior spread fingers (Fig. 2). They may be distinguished from raccoon tracks, in Opossums usually live alone, having a b which hind prints appear to be made home range of 10 to 50 acres (4 to 20 by little feet. The hind foot of an opos- ha). Young appear to roam randomly sum looks like a distorted hand. until they find a suitable home range. Usually they are active only at night. The mating season is January to July in Range warmer parts of the range but may start a month later and end a month Opossums are found in eastern, earlier in northern areas. Opossums central, and west coast states. Since may raise 2, rarely 3, litters per year. 1900 they have expanded their range The opossum is the only marsupial in northward in the eastern United North America. Like other marsupials, States. They are absent from the the blind, helpless young develop in a Rockies, most western plains states, pouch. They are born 13 days after and parts of the northern United mating. The young, only 1/2 inch (1.3 States (Fig. 3). cm) long, find their way into the female’s pouch where they each attach Habitat to one of 13 teats. An average of 7 young are born. They remain in the pouch for 7 to 8 weeks. The young Habitats are diverse, ranging from remain with the mother another 6 to 7 c arid to moist, wooded to open fields. weeks until weaned. Opossums prefer environments near streams or swamps. They take shelter Most young die during their first year. in burrows of other animals, tree Those surviving until spring will breed cavities, brush piles, and other cover. in that first year. The maximum age in They sometimes den in attics and the wild is about 7 years. garages where they may make a Although opossums have a top run- messy nest. ning speed of only 7 miles per hour (11.3 km/hr), they are well equipped Food Habits to escape enemies. They readily enter burrows and climb trees. When threat- Foods preferred by opossums are ani- ened, an opossum may bare its teeth, mal matter, mainly insects or carrion. growl, hiss, bite, screech, and exude a Opossums also eat considerable smelly, greenish fluid from its anal amounts of vegetable matter, espe- glands. If these defenses are not suc- cially fruits and grains. Opossums liv- cessful, an opossum may play dead. ing near people may visit compost When captured or surprised during piles, garbage cans, or food dishes daylight, opossums appear stupid and intended for dogs, cats, and other pets. inhibited. They are surprisingly Fig. 3. Range of the opossum in North America.

D-60 intelligent, however. They rank above dogs in some learning and discrimina- tion tests.

Damage

Although opossums may be considered desirable as game animals, certain individuals may be a nuisance near homes where they may get into garbage, bird feeders, or pet food. They may also destroy poultry, game birds, and their nests.

Fig. 4. Cage trap (set position). Legal Status

Laws protecting opossums vary from state to state. Usually there are open Fig. 5. Leghold trap and sets for opossum. seasons for hunting or trapping opos- Dirt hole set sums. It is advisable to contact local wildlife authorities before removing nuisance animals.

Damage Prevention and Bait Control Methods Leghold trap (coilspring type in set position) Spring levers Exclusion Prevent nuisance animals from entering structures by closing openings to cages and pens that house poultry. Pan adjustment screw Opossums can be prevented from climbing over wire mesh fences by Coil springs installing a tightly stretched electric fence wire near the top of the fence 3 Extra swivel inches (8 cm) out from the mesh. Fas- ten garbage can lids with a rubber strap.

Traps Opossums are not wary of traps and may be easily caught with suitable- Cubby sets sized box or cage traps (Fig. 4). No. 1 or 1 1/2 leghold traps also are effective. Set traps along fences or trail- ways. Dirt hole sets or cubby sets are effective (Fig. 5). A dirt hole is about 3 inches (8 cm) in diameter and 8 inches (20 cm) deep. It extends into the earth at a 45o angle. The trap should be set at the entrance to the hole. A cubby is a small enclosure made of rocks, logs, or a box. The trap is set at the entrance to the cubby. The purpose of the dirt hole or cubby is to position the animal so

D-61 that it will place its foot on the trap. Fig. 6. Body-gripping trap and running pole set. Place bait such as cheese, or slightly spoiled meat, fish, or fruit in the dirt hole or cubby to attract the animal. Using fruit instead of meat will reduce Dog Jaws the chance of catching cats, dogs, or skunks. Spring A medium-sized body-gripping (kill type) trap will catch and kill opossums. Place bait behind the trap in such a way that the animal must pass through the trap to get it. Body- Trigger gripping traps kill the captured animal quickly. To reduce chances of catching pets, set the trap above ground on a running pole (Fig. 6). Body-gripping trap (set position) Shooting

A rifle of almost any caliber or a shotgun loaded with No. 6 shot or larger will effectively kill opossums. Use a light to look for opossums after dark. If an opossum has not been alarmed, it will usually pause in the light long enough to allow an easy shot. Once alarmed, opossums do not run rapidly. They will usually climb a nearby tree where they can be located with a light. Chase running opossums on foot or with a dog. If you lose track, run to the last place where you saw the animal. Stop and listen for the sound of claws on bark to locate the tree the animal is climbing. Sometimes opossums can be approached quietly and killed by a strong blow with a club, but they can be surprisingly hard to kill in this man- Running pole set ner. They can be taken alive by firmly grasping the end of the tail. If the animal begins to “climb its tail” to reach your hand, lower the animal until it touches the ground. This will distract the opossum and cause it to try to escape by crawling. Opossums can carry rabies, so wear heavy gloves and be wary of bites. Euthanize unwanted animals humanely with carbon dioxide gas, or release them several miles from the point of capture.

D-62 Economics of Damage For Additional Lay, D. W. 1942. Ecology of the opossum in eastern Texas. J. Mammal. 23:147-159. and Control Information McManus, J. J. 1974. Didelphis virginiana. Mammal. Species 40:1-6. No data are available; however, it is Fitch, H. S., and L. L. Sandidge. 1953. Ecology of Reynolds, H. C. 1945. Some aspects of the life usually worthwhile to remove a par- the opossum on a natural area in northeastern Kansas. Univ. Kansas Publ. history and ecology of the opossum in ticular animal that is causing damage. Museum Nat. Hist. 7:305-338. central Missouri. J. Mammal. 26:361-379. Gardner, A. L. 1982. Virginia opossum. Pages Schwartz, C. W., and E. R. Schwartz. 1981. The Acknowledgments 3-36 in J. A. Chapman and G. A. Feldhamer, wild mammals of Missouri, rev. ed. Univ. eds. Wild mammals of North America: Missouri Press, Columbia, 356 pp. biology, management, and economics. The Seidensticker, J., M. A. O’Connell, and A. J. T. Much of the information on habitat, food habits, Johns Hopkins Univ. Press, Baltimore, Johnsingh. 1987. Virginia opossum. Pages and general biology comes from J. J. Maryland. McManus (1974) and A. L. Gardner (1982). 246-263 in M. Novak, J. A. Baker, M. E. The manuscript was read and improved by Hall, E. R., and K. R. Kelson. 1959. The Obbard, and B. Malloch, eds. Wild furbearer Jim Byford and Robert Timm. mammals of North America, Vol. 1. Ronald management and conservation in North Press Co., New York. 546 pp. America. Ontario Ministry Nat. Resour. Figures 1, 2a, 2c, and 3 from Schwartz and Toronto. Schwartz (1981). Hamilton, W. J., Jr. 1958. Life history and economic relations of the opossum (Didelphis Figure 2b by Jill Sack Johnson. marsupialis virginiana) in New York State. Figures 4, 5, and 6 by Michael D. Stickney, from Cornell Univ. Agric. Exp. Sta. Memoirs the New York Department of Environmental 354:1-48. Editors Conservation publication “Trapping Howard, R., L. Berchielli, C. Parsons, and M. Scott E. Hygnstrom Furbearers, Student Manual” (1980), by R. Brown. 1980. Trapping furbearers, student Robert M. Timm Howard, L. Berchielli, C. Parsons, and M. manual. State of New York, Dep. Environ. Gary E. Larson Brown. The figures are copyrighted and are Conserv. 59 pp. used with permission.

D-63 D-64 Reginald H. Barrett Department of Environmental Science, Policy, and Management WILD PIGS University of California Berkeley, California 94720

Grant H. Birmingham USDA-APHIS- Animal Damage Control (retired) Modesto, California 95353

Fig. 1. Feral hog (left) and European wild boar (right). Both are the species Sus scrofa.

Damage Prevention and Toxicants Identification Control Methods None are registered. Wild pigs (Sus scrofa, Fig. 1) include Trapping Exclusion both feral hogs (domestic swine that Stationary corral trap. have escaped captivity) and wild boar, Heavy-mesh wire fences and electric native to Eurasia but introduced to fences may be effective, especially Portable drop gate trap. North America to interbreed with feral around gardens and other small Leg snare. hogs. Like domestic hogs, they may be areas. any color. Their size and conformation Shooting Frightening depend on the breed, degree of Sport hunting, especially with dogs, hybridization with wild boar, and No methods are effective. can reduce pig populations in local level of nutrition during their growing Repellents areas. period. None are registered. Wild boar have longer legs and larger heads with longer snouts than feral

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 D-65 Great Plains Agricultural Council Wildlife Committee hogs. The color of young boar is are generally restricted to areas below the day, they will remain in heavy generally reddish brown with black snowline and above freezing tempera- cover at that time and feed at night. In longitudinal “watermelon” stripes. As tures during the winter. Wild pigs fre- periods of hot weather, wild pigs the young develop, the stripes begin to quent livestock-producing areas. They remain in the shade in wallows during disappear and the red changes to prefer mast-producing hardwood for- the day and feed at night. brown and finally to black. Both the ests but will frequent conifer forests as The wild pig is the most prolific large male feral hog and wild boar have well. In remote areas or where human wild mammal in North America. continuously growing tusks. Wild boar activities are minimal, they may use Given adequate nutrition, a wild pig and feral hogs hybridize freely; there- open range or pastures, particularly at population can double in just 4 fore, the term wild pig is appropriate as night. During periods of hot weather, months. Feral hogs may begin to breed a generic term for these animals. wild pigs spend a good deal of time before 6 months of age, if they have a wallowing in ponds, springs, or high-quality diet. Sows can produce 2 streams, usually in or adjacent to Range litters per year and young may be born cover. at any time of the year. Wild boar usu- Christopher Columbus first intro- ally do not breed until 18 months of duced members of the family Suidae Food Habits age and commonly have only 1 litter into North America in 1493 in the West per year unless forage conditions are Indies (Towne and Wentworth 1950). Types of food vary greatly depending excellent. Like domestic animals, the The first documented introduction to on the location and time of year. Wild litter size depends upon the sow’s age, the United States was in Florida by de pigs will eat anything from grain to nutritional intake, and the time of year. Soto in 1593. More introductions fol- carrion. They may feed on under- Litter sizes of feral hogs in northern lowed in Georgia and the Carolinas, ground vegetation during periods of California average 5 to 6 per sow which established free-ranging popula- wet weather or in areas near streams (Barrett 1978). Wild boar usually have tions in the Southeast. Free-ranging and underground springs. Acorns or litter sizes of 4 to 5 but may have as practices continued until they became other mast, when available, make up a many as 13 (Pine and Gerdes 1973). illegal in the mid-twentieth century. good portion of their diet. Wild pigs Populations of unclaimed hogs gather in oak forests when acorns fall, Damage and Damage increased and spread throughout the and their movements will generally Southeast. Domestic hogs were Identification not be as great during this period. In released in California in 1769 and free- the winters of poor mast years, wild ranging practices there also resulted in Wild pigs can cause a variety of dam- pigs greatly increase their range and a feral hog population. European wild age. The most common complaint is consume greater quantities of under- boar were released at Hooper Bald, rooting (sometimes called grubbing), ground plant material, herbaceous North Carolina, in 1912, and from resulting in the destruction of crops plants, and invertebrates (Singer 1981). there introduced to California in 1925. and pastures. Damage to farm ponds Stomach analyses indicate that wild and watering holes for livestock is Wild pigs are found throughout the hogs ingest flesh from vertebrates, but another common problem. Predation southeastern United States from Texas the extent to which animals are taken on domestic stock and wildlife has east to Florida and north to Virginia; as prey or carrion is not known. Wild been a lesser problem in North and in California, Hawaii, Puerto Rico, pigs are capable of preying on lambs America. and the Virgin Islands. The local intro- (Pavlov et al. 1981), as well as goat duction of these animals for hunting kids, calves, and exotic game. Damage to crops and rangeland by purposes occurred in North Carolina, wild pigs is easily identified. Rooting Tennessee, Texas, Louisiana, and Cali- in wet or irrigated soil is generally fornia. The National Park Service General Biology, quite visible, but can vary from an area reports feral hogs in 13 National Park Reproduction, and of several hundred square feet (m2) or Service areas. They occur in many Behavior more to only a few small spots where state parks as well (Mayer and Brisbin the ground has been turned over. Rooting destroys pasture, crops, and 1991). Feral hogs are also found in Wild pigs are intelligent animals and native plants, and can cause soil ero- Hawaii, Australia, New Zealand, and readily adapt to changing conditions. sion. Wallows are easily seen around several other South Pacific Islands. They may modify their response to ponds and streams. Tracks of adult humans fairly rapidly if it benefits hogs resemble those made by a 200- Habitat their survival. Wild boar have a pound (90-kg) calf. Where ground is greater capacity to invade colder and soft, dewclaws will show on adult hog A variety of habitats, from tidal more mountainous terrain than do tracks (Fig. 2). marshes to mountain ranges, are suit- other wild pigs. Feral hogs feed during able for wild pigs. They prefer cover of daylight hours or at night, but if hunt- Wild pig depredation on certain forest dense brush or marsh vegetation. They ing pressure becomes too great during tree seedlings has been a concern of

D-66 mesh may be of some help, but it is difficult to maintain over large areas. Electric fencing has been used effectively in New South Wales, Australia. See the Deer chapter for details on electric fencing.

Frightening No methods are effective.

Repellents None are registered.

Toxicants There are no toxicants currently regis- Fig. 2. Tracks of the feral hog (left) and European wild boar (right). tered for controlling wild pigs in the United States. foresters in the South and West. Wild are associated with domestic livestock. pigs have destroyed fragile plant Cholera, swine brucellosis, trichinosis, Trapping communities in Great Smoky Moun- bovine tuberculosis, foot and mouth Cage Traps. Trapping, especially tains National Park and other pre- disease, African swine fever, and where pig densities are high, is prob- serves. They have been known to pseudorabies are all diseases that may ably the most effective control method. damage fences when going into gar- be transmitted to livestock (Wood and Traps may not be effective, however, dens and can do considerable damage Barrett 1979). Bovine tuberculosis was during fall and winter when acorns or to a lawn or golf course in a single transmitted to beef cattle by wild hogs other preferred natural foods are avail- night. on the Hearst Ranch in California in able. Hogs seem to prefer acorns over 1965. Pork that was infected with hog In California, wild pigs have entered grain and other baits. Leg snares and cholera brought into Kosrae Island in turkey pens, damaging feeders, eating hunting may be more productive con- the East Carolinas resulted in the deci- the turkey feed, and allowing birds to trol methods during fall and winter. mation of all domestic and feral hogs escape through damaged fences. Wild Stationary corral-type traps and box on the island. pigs in New South Wales, Australia, traps have been used with success. The reportedly killed and ate lambs on corral or stationary trap is permanent lambing grounds. Producers in Texas Legal Status and should be constructed in locations and California reported to USDA- where large populations of hogs are APHIS-ADC that 1,473 sheep, goats, Wild pigs are game mammals in Cali- evident and where more than one hog and exotic game animals were killed fornia, Texas, Tennessee, North Caro- can be trapped at a time (Fig. 3). Build by wild pigs in 1991. Predation usually lina, Puerto Rico, Hawaii, and Florida the trap out of steel fence posts and 2 x occurs on lambing or calving grounds, (Wood and Barrett 1979, Mayer and 4-inch (5.1 x 10.2-cm) welded 12-gauge and some hogs become highly efficient Brisbin 1991). In California, a depreda- wire fencing. A gate frame can be predators. Depredation to calves and tion permit is required from the made from 2 x 4-inch (5.1 x 10.2-cm) lambs can be difficult to identify be- Department of Fish and Game to con- boards. Make doors from 3/4-inch cause these small animals may be duct a control program or to take dep- (1.9-cm) plywood and mount them so killed and completely consumed, leav- redating animals. Contact your state that they open inward and close auto- ing little or no evidence to determine wildlife agency to determine if a per- matically with screen door springs. whether they were killed or died of mit is required. Heavier material may be used for the other causes and then were eaten. De- gate and frame in areas where excep- termining predation by wild hogs is Damage Prevention and tionally large hogs are to be trapped. possible if carcasses are not entirely Control Methods Also, more steel fence posts may be eaten, because feral hogs follow a char- needed to reinforce the wire fencing. The wire fencing should be put on the acteristic feeding pattern on lambs Exclusion (Pavlov and Hone 1982). Photographs ground as well as at the top of the trap and additional information on wild pig Fencing is generally not practical to prevent hogs from going under the predation may be found in the booklet except in small areas around yards sides or over the top. Fasten the sides by Wade and Bowns (1982). and gardens. Heavy wire and posts to the top and bottom. One or two must be used, but if hogs are persis- small hogs can be left inside the trap Always be aware of the potential for with adequate food and water to act as disease transmission when feral hogs tent, exclusion is almost impossible. Electric fencing on the outside of the decoys.

D-67 2" x 4" x 24' wood 36" x 48" x 3/4" plywood 36' x 2" x 4" mesh welded wire 4 6" strap hinges 2 12" screen door springs 8 6" steel fence posts 4 lbs. 16-penny nails 1 lb. 12-penny nails 2 lbs. 1 1/2" staples 1 100' 12-gauge wire Steel fence post

6" 18" Spring

2" x 4" Mesh welded wire (12 gauge)

48" 96"

Front Side

Fig. 3. Stationary hog trap.

A portable trap with a drop gate has used in the construction of these traps and escapes can occur even out of been used very effectively and can be be strong and heavy enough to pre- well-built traps. A well-placed shot to moved from one area to another (Fig. vent escapes. Corral-type traps have the head from a large-caliber rifle will 4). It is especially effective where hogs captured up to 104 hogs in a single kill the hog instantly without greatly occur intermittently. Build the trap out night and may have to be reinforced alarming other hogs in the trap. Shoot of 2 x 4-inch (5.1 x 10.2-cm) welded with extra fence posts and heavier the largest hog first, if possible. When 12-gauge wire over a 2 x 4-inch (5.1 x fencing material. a trapping program is being con- 10.2-cm) wooden frame using a 3/4- ducted, all hunting in the area should Persistence and dedication are inch (1.9-cm) plywood drop gate. Place cease, especially the use of dogs, as required if a feral hog control program loose barbed wire fencing around the this may pressure the pigs to move to is to be successful. Traps must be outside of the trap to prevent livestock another area. checked daily to be reset and to from entering and to protect both the replace bait when needed. Many times A prebaiting program should be con- traps and bait material. When traps are control measures fail because opera- ducted before a trapping program is not in use make sure trap doors are tors fail to check their traps or provide initiated. Grains such as barley, corn, locked shut to prevent the possibility bait in adequate amounts. Trapping or oats make good attractants, as do of trapping livestock. hogs that are feeding on acorns may be vegetables or fruits, if a supply is avail- There are a number of different styles difficult because they seem to prefer able. If bait is accepted by hogs, re- of live or cage traps. The two de- acorns to grain or other baits. place it daily. Make sure enough bait is scribed here have been used effectively out to induce hogs to return the next Traps should be checked from a dis- in California. As many as 14 hogs have day; if no feed is available, they may tance when possible. If several large been trapped during a night in one move on to other feeding areas. A hogs are in a trap, the presence of a trap. It is important that the material place where hogs have gathered in the person or vehicle will frighten them

D-68 8 2" x 4" x 6' 4 2" x 4" x 3' 4" 6 2" x 4" x 2' 1 3/4" x 24" x 36" plywood 2 3' x 6' welded-wire fencing (12-gauge) 2 2' x 6' welded-wire fencing (12-gauge) 1 2' x 3' welded-wire fencing (12-gauge) Front 2 3" strap hinges 1 12" x 20" plywood 2 8' cable or nylon 2 1" x 1" steel pin 16-penny nails

Plywood drop gate

1" 2"

24"

2" x 4" Welded-wire fencing (12-gauge)

Bait

Front

Fig. 4. Portable hog trap with drop gate

D-69 past and seem to frequent often, is Economics of Damage Bratton, S. P. 1974. The effect of the European probably a good place to build a cor- wild boar (Sus scrofa) on the high elevation and Control vernal flora in Great Smoky Mountains ral-type trap. If only one or two hogs National Park. Bull. Torrey Bot. Club are attracted to the prebait, a portable 101:198-206. In most areas it is unlikely that wild trap should be installed. pigs can be exterminated. It is theoreti- Mayer, J. J., and I. L. Brisbin, Jr. 1991. Wild pigs If a swing gate corral trap is prebaited, cally possible, but the cost to do so is of the United States: their history, morphology, and current status. Univ. Press, prop the doors open so that hogs can usually prohibitive. Landowners must Athens, Georgia. 313 pp. move in and out. When it appears that generally accept the fact that they will Pavlov, P. M., and J. Hone. 1982. The behavior of the number of hogs that are accepting always have some wild pigs and feral pigs, Sus scrofa, in a flock of lambing the bait has peaked, position the doors should therefore plan for a long-term ewes. Australian Wildl. Resour. 9:101-109. so that they will close after hogs enter control program. Pavlov, P. M., J. Hone, R. J. Kilgour, and H. the trap. Feral hog damage can be extensive and Pedersen. 1981. Predation by feral pigs on Steel Traps. Merino lambs at Nyngan, New South Wales. Steel leghold traps are costly if not controlled. Control for Australian J. Exp. Agric. An. Husb. 21:570- not recommended for pigs. disease suppression is extremely 574. expensive because many hogs need to Leg Snares. Leg snares can be used Pine, D. S., and C. S. Gerdes. 1973. Wild pigs in be eliminated. Crop depredations may with success where terrain prohibits Monterey county, California. California Fish cease after one or two hogs are shot or Game 59:126-137. the use of cage traps. Snares are not trapped, or intermittent hunting pres- recommended if livestock, deer, or Plant, J. W. 1977. Feral pigs predators of lambs. sure is put on them. They simply move other nontarget animals are in the area. Agric. Gazette, New South Wales Dep. to new areas. If depredations are Agric. Vol. 8, No.5. An ideal location for leg snares is at a heavy enough to require a reduction in fence where hogs are entering pens or Plant, J. W. 1980. Electric fences give pigs a the overall population then a program shock. Agric. Gazette, New South Wales on trails that hogs are traveling. Fasten can be very costly, depending on the Dep. Agric. Vol. 91, No. 2. the snare to a heavy drag, such as an size of the area involved. oak limb, 6 to 12 feet (1.8 to 3.6 m) in Singer, F. J. 1981. Wild pig populations in the national parks. Environ. Manage. 5:263-270. length, or longer if large hogs are in the area. Make sure the size of the Singer, F. J., D. K. Otto, A. R. Tipton, and C. P. Acknowledgments Hable. 1981. Home range movements and cable is heavy enough to hold a large habitat use of wild boar. J. Wildl. Manage. hog. Figures 1 and 2 by Emily Oseas Routman. 45:343-353. Figures 3 and 4 by Marilyn Murtos, US Bureau Shooting Sterner, J. D., and R. H. Barrett. 1991. Removing of Reclamation, Sacramento, California. feral pigs from Santa Cruz Island, California. Sport hunting is used in certain areas Trans. Western Sect. The Wildl. Soc. 27:47-53. to reduce wild pig densities and can be For Additional Tisdell, C. A. 1982. Wild pigs: environmental a source of revenue for ranchers. Suc- pest or economic resource? Pergamon Press, cess is highly dependent on local situa- Information New York. 445 pp. tions and terrain. Hunting is not Towne, C. W., and E. N. Wentworth. 1950. Pigs recommended if there is a serious dep- Barrett, R. H. 1970. Management of feral hogs on from Cave to Cornbelt. Univ. Oklahoma private lands. Trans. Western Sect. Wildl. Press, Norman. 305 pp. redation or disease problem. Unsuc- Soc. 6:71-78. cessful hunting will make wild pigs Wade, D. A., and J. E. Bowns. 1982. Procedures Barrett, R. H. 1977. Wild pigs in California. for evaluating predation on livestock and keep to cover and change their feeding Pages 111-113 in G. W. Wood, ed. Research wildlife. Bull. B-1429, Texas A & M Univ., habits. The use of dogs can increase and management of wild hog populations. College Station. 42 pp. hunter success. Good dogs chase pigs Symp. Belle W. Baruch For. Sci. Inst., Clemson Univ., Georgetown, South Carolina. Wood, C. W., and R. Barrett. 1979. Status of wild from cover where they can be shot by pigs in the United States. Wildl. Soc. Bull. hunters. Barrett, R. H. 1978. The feral hog on the Dye 7:237-246. Creek Ranch, California. Hilgardia 46:283- 355. Barrett, R. H., B. L. Goatcher, P. J. Gogan, and E. Editors L. Fitzhugh. 1988. Removing feral pigs from Scott E. Hygnstrom Annadel State Park. Trans. Western Sect. Robert M. Timm Wildl. Soc. 24:47-52. Gary E. Larson

D-70 Sanford D. Schemnitz Professor Wildlife Science PRONGHORN New Mexico State University Las Cruces, New Mexico 88003 ANTELOPE

Fig. 1. Pronghorn antelope, Antilocapra americana

Identification Damage Prevention and Repellents The pronghorn (Antilocapra americana) Control Methods None are registered. is not a true antelope but in a family by Exclusion Toxicants itself (Antilocapridae). It is native only to North America. Woven wire and electric fence. None are registered. The pronghorn is the only North Cultural Methods Trapping American big game animal that has Plant tall-growing crops near damaged Corral trap. branched horns, from which its name fields. derives. Pronghorns have true horns Shooting — derived from hair — not antlers. Frightening Encourage legal hunting. The horns have an outer sheath of Gas-operated exploders. fused, modified hair that covers a permanent, bony core. Pronghorns shed the hollow outer sheath each year in October or November and grow a new set by July. Both bucks and does have

In the late 1800s and early 1900s most 16" Great Plains state legislatures passed laws making it unlawful to kill, ensnare, or trap pronghorns. Fig. 3. Specifications for livestock fences con- Pronghorns were given complete pro- structed on antelope ranges, recommended by tection for nearly 50 years. In the 1940s the US Bureau of Land Management Regional Fencing Workshop (1974).

D-72 Pronghorns are social animals, gather- Cultural Methods other Great Plains states often charge ing in relatively large herds. In spring, $200 or more for trespass fees per Plant tall crops, such as corn, as a bar- however, bucks are alone or form hunter. Guided hunts may yield $600 rier between rangelands and small small groups. Pronghorns breed dur- to $800 or more per animal taken. In grain fields to help reduce damage. ing September and October. Bucks are addition, many landowners derive Alfalfa fields adjacent to rangeland are polygamous, collecting harems of 7 to aesthetic pleasure from observing more vulnerable and apt to suffer 10 does, which they defend from other pronghorns. Some states provide eco- damage. Pronghorns often move out bucks. Bucks and does begin breeding nomic reimbursement for crop dam- of pastures that are heavily grazed by at 15 to 16 months of age. Usually 2 age. In Wyoming, costs of pronghorn cattle to ungrazed areas. kids (young) are born 8 months after crop damage on private land, includ- mating. The kids are grayish brown at Frightening ing administration (for example, birth and usually weigh 5 to 7 pounds salaries and travel) averaged $169,453 (2.3 to 3.2 kg). Does nurse their kids Propane or acetylene exploders may per year (1987 to 1991). Similar ante- and keep them hidden until they are provide temporary relief from crop lope crop damage costs in Colorado strong enough to join the herd, usually damage. These devices are also used for the same period averaged $5,510 at 3 weeks of age. By fall, the kids can for bird damage control (see Bird per year. take care of themselves and are some- Dispersal Techniques and Supplies what difficult to distinguish from and Materials). Acknowledgments adults. Repellents Figure 1 by Charles W. Schwartz, adapted from Pronghorns are relatively disease- and Yoakum (1978) by Emily Oseas Routman. None are registered. parasite-free. Losses occur from preda- Figure 2 from Burt and Grossenheider (1976), tion, primarily coyote, and starvation adapted by Jill Sack Johnson. during severe winters with prolonged Toxicants Figure 3 from the US Bureau of Land deep snow. None are registered, and poisoning Management (1974). pronghorns also violates state laws Damage that protect them as game animals. For Additional Pronghorns sometimes cause damage Trapping Information to grain fields, alfalfa, and haystacks In areas where crop depredation and Kitchen, D. W., and B. W. O’Gara. 1982. during the winter. Damage occurs livestock competition are severe, Pronghorn. Pages 960-971 in J. A. Chapman from feeding, bedding, and trampling. and G. A. Feldhamer, eds. Wild mammals of pronghorns can be readily herded with North America: biology, management and aircraft into corral traps. After capture, economics. The Johns Hopkins Univ. Press, Legal Status they can be translocated into suitable Baltimore, Maryland. unoccupied habitat. This technique is Pronghorns have game-animal status O’Gara, B. W. 1978. Antilocapra americana. for use only by federal or state wildlife in all of the western states. Permits are Mammal. Sp. 90:1-7. agencies. required to trap or shoot pronghorns. US Bureau of Land Management. 1974. Proc. Regional Fencing Workshop. Washington, Shooting DC. 74 pp. Damage Prevention and Encourage legal hunting near agricul- Yoakum, J. D. 1978. Pronghorn. Pages 102-122 in Control Methods tural fields to help curtail crop dam- J. L. Schmidt and D. L. Gilbert, eds. Big game of North America. Wildl. Manage. Inst. and Exclusion age. Shooting permits are available in Stackpole Books, Harrisburg, Pennsylvania. some states to remove pronghorns that Yoakum, J. D., and B. W. O’Gara. 1992. Woven wire fences of 8-inch (20-cm) are causing significant damage outside mesh, 48 inches (1.2 m) high, near agri- Pronghorn antelope: ecology and of the regular hunting season. management. Wildl. Manage. Inst. (in prep). cultural fields will help to curtail damage. Electric fences with two wires Yoakum, J. D., and D. E. Spalinger. 1979. Economics of Damage American pronghorn antelope - articles spaced at 8 to 10 inches (20 to 25 cm) published in the Journal of Wildlife and 3 feet (90 cm) above the ground and Control Management 1937-1977. The Wildl. Soc., will discourage pronghorns from Washington, DC. 244 pp. Competition with livestock and occa- entering croplands. A single strand of sional damage to agricultural crops electric wire painted with molasses as should be weighed against the eco- an attractant and 30 to 36 inches (76 to Editors nomic value of pronghorns as game 91 cm) above the ground will discour- Scott E. Hygnstrom animals. Landowners in Texas and Robert M. Timm age pronghorn access. Gary E. Larson

D-73 D-74 Scott R. Craven Extension Wildlife Specialist Department of Wildlife Ecology COTTONTAIL RABBITS University of Wisconsin, Madison Madison, Wisconsin 53706

Fig. 1. Eastern cottontail rabbit, Sylvilagus floridanus

Damage Prevention and Toxicants Introduction Control Methods* None are registered. Rabbits mean different things to differ- Exclusion Trapping ent people. For hunters, the cottontail rabbit is an abundant, sporting, and Low fences are very effective around Commercial live traps or homemade tasty game animal. However, veg- gardens or shrubs. box traps are effective, particularly etable and flower gardeners, farmers, during winter in northern states. Hardware cloth cylinders will protect and homeowners who are suffering fruit trees and ornamental plants. Shooting damage may have very little to say in favor of cottontails. They can do con- Sport hunting and/or routine shooting Habitat Modification siderable damage to flowers, veg- of problem individuals are very etables, trees, and shrubs any time of Removal of brush piles, debris, effective methods. dumps, and other cover makes an the year and in places ranging from area less suitable for rabbits. Other Methods suburban yards to rural fields and tree plantations. Control is often necessary Many “gimmick” solutions are avail- Frightening to reduce damage, but complete exter- able but unreliable. For example, mination is not necessary, desirable, or Several methods are available but none sections of garden hose to simulate even possible. are reliable. snakes, water-filled jugs to create Repellents frightening, distorted reflections. Rabbits usually can be accepted as interesting additions to the backyard A wide variety of commercial formula- or rural landscape if control techniques tions is available; most are taste are applied correctly. Under some repellents based on the fungicide unusual circumstances, control of thiram. Home-remedy types may *Most methods apply to all rabbit and hare damage may be difficult. provide some relief. species.

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 D-75 Great Plains Agricultural Council Wildlife Committee Damage control methods include color. They have large ears, though removal by live trapping or hunting, smaller than those of jackrabbits, and exclusion, and chemical repellents. In the hind feet are much larger than the general, no toxicants or fumigants are forefeet. The tail is short and white on registered for rabbit control; however, the undersurface, and its similarity to a state regulations may vary. Frighten- cotton ball resulted in the rabbit’s coming devices may provide a sense of mon name. security for the property owner, but they rarely diminish rabbit damage. Range Identification The eastern cottontail’s range includes the entire United States east of the There are 13 species of cottontail rab- Rocky Mountains and introductions bits (genus Sylvilagus), nine of which further west. It extends from southern are found in various sections of North New England along the Canadian bor- Fig. 2. Range of the eastern cottontail in North America north of Mexico. All nine are der west to eastern Montana and south America. similar in general appearance and into Mexico and South America (Fig. behavior, but differ in size, range, and 2). The most common species of the habitat. Such differences result in a western United States include the wide variation of damage problems, or desert cottontail (S. auduboni, Fig. 3), lack of problems. The pygmy rabbit (S. and mountain cottontail (S. muttalli, idahoensis), found in the Pacific North- Fig. 4). Refer to a field guide or sug- west, weighs only 1 pound (0.4 kg), gested readings if other species of the while the swamp rabbit (S. aquaticus), genus Sylvilagus are of interest. found in the southeastern states as far north as southern Illinois, may weigh Habitat up to 5 pounds (2.3 kg). Most species prefer open, brushy, or cultivated Cottontails do not distribute them- areas but some frequent marshes, selves evenly across the landscape. swamps, or deserts. The swamp rabbit They tend to concentrate in favorable and the marsh rabbit (S. palustris) are habitat such as brushy fence rows or strong swimmers. The eastern cotton- field edges, gullies filled with debris, Fig. 3. Range of the desert cottontail in North tail (S. floridanus) is the most abundant brush piles, or landscaped backyards America. and widespread species. For the pur- where food and cover are suitable. poses of the discussion here about They are rarely found in dense forests damage control and biology, the east- or open grasslands, but fallow crop ern cottontail (Fig. 1) will be consid- fields, such as those in the Conserva- ered representative of the genus. tion Reserve Program, may provide Cottontail rabbits must be distin- suitable habitat. guished from jackrabbits and other Cottontails generally spend their entire hares, which are generally larger in lives in an area of 10 acres or less. size and have longer ears. Jackrabbits Occasionally they may move a mile or are discussed in another chapter of this so from summer range to winter cover book. or to a new food supply. Lack of food The eastern cottontail rabbit is approx- or cover is usually the motivation for a imately 15 to 19 inches (37 to 48 cm) in rabbit to relocate. In suburban areas, length and weighs 2 to 4 pounds (0.9 rabbits are numerous and mobile to 1.8 kg). Males and females are basi- enough to fill any “empty” habitat cally the same size and color. Cotton- created when other rabbits are Fig. 4. Range of the mountain cottontail in North tails appear gray or brownish gray in removed. Population density varies America. the field. Closer examination reveals a with habitat quality, but one rabbit per grizzled blend of white, gray, brown, acre is a reasonable average. and black guard hairs over a soft gray- Contrary to popular belief, cottontails Underground dens are used primarily ish or brownish underfur, with a char- do not dig their own burrows, as the in extremely cold or wet weather and acteristic rusty brown spot on the nape European rabbit does. Cottontails use to escape pursuit. Brush piles and of the neck. Rabbits molt twice each natural cavities or burrows excavated other areas of cover are often adequate year, but remain the same general by woodchucks or other animals. alternatives to burrows.

D-76 In spring and fall, rabbits use a grass Food Habits, Damage, members of the pea family are among or weed shelter called a “form.” The and Damage the shrubs damaged. form is a nestlike cavity on the surface Evergreens seem to be more suscep- of the ground, usually made in dense Identification tible to rabbit damage in some areas cover. It gives the rabbit some protec- The appetite of a rabbit can cause than in others. Young trees may be tion from weather, but is largely used problems every season of the year. clipped off, and older trees may be for concealment. In summer, lush Rabbits eat flowers and vegetables in deformed or killed. green growth provides both food and spring and summer. In fall and winter, shelter, so there is little need for a they damage and kill valuable woody The character of the bark on woody form. plants. plants also influences rabbit browsing. Most young trees have smooth, thin General Biology and Rabbits will devour a wide variety of bark with green food material just flowers. The one most commonly Reproduction beneath it. Such bark provides an easy- damaged is the tulip; they especially to-get food source for rabbits. The like the first shoots that appear in early thick, rough bark of older trees often Rabbits live only 12 to 15 months, and spring. discourages gnawing. Even on the probably only one rabbit in 100 lives to same plant, rabbits avoid the rough see its third fall, yet they make the The proverbial carrot certainly is not the only vegetable that cottontails eat. bark but girdle the young sprouts that most of the time available to them. have smooth bark. Cottontails can raise as many as 6 lit- Anyone who has had a row of peas, ters in a year. Typically, there are 2 to 3 beans, or beets pruned to ground level Rabbit damage can be identified by the litters per year in northern parts of the knows how rabbits like these plants. characteristic appearance of gnawing cottontail range and up to 5 to 6 in Only a few crops—corn, squash, on older woody growth and the clean- southern areas. In the north (Wiscon- cucumbers, tomatoes, potatoes, and cut, angled clipping of young stems. sin), first litters are born as early as late some peppers—seem to be immune Distinctive round droppings in the im- March or April. In the south (Texas), from rabbit problems. mediate area are a good sign of their litters may be born year-round. Litter Equally annoying, and much more presence too. size also varies with latitude; rabbits serious, is the damage rabbits do to Rabbit damage rarely reaches econo- produce 5 to 6 young per litter in the woody plants by gnawing bark or clip- mic significance in commercial fields north, 2 to 3 in the south. The rabbit’s ping off branches, stems, and buds. In or plantations, but there are excep- gestation period is only 28 or 29 days, winter in northern states, when the tions. For example, marsh rabbits have and a female is usually bred again ground is covered with snow for long been implicated in sugarcane damage within a few hours of giving birth. periods, rabbits often severely damage in Florida. Growers should always be Rabbits give birth in a shallow nest expensive home landscape plants, alert to the potential problems caused depression in the ground. Young cot- orchards, forest plantations, and park by locally high rabbit populations. tontails are born nearly furless with trees and shrubs. Some young plants their eyes closed. Their eyes open in 7 are clipped off at snow height, and Legal Status to 8 days, and they leave the nest in 2 large trees and shrubs may be com- to 3 weeks. pletely girdled. When the latter hap- In most states, rabbits are classified as pens, only sprouting from beneath the Under good conditions, each pair of game animals and are protected as damage or a delicate bridge graft rabbits could produce approximately such at all times except during the around the damage will save the plant. 18 young during the breeding season. legal hunting season. Some state regu- Fortunately, this potential is rarely A rabbit’s tastes in food can vary con- lations may grant exceptions to prop- reached. Weather, disease, predators, siderably by region and season. In gen- erty owners, allowing them to trap or encounters with cars and hunters, and eral, cottontails seem to prefer plants shoot rabbits outside the normal hunt- other mortality factors combine to of the rose family. Apple trees, black ing season on their own property. keep a lid on the rabbit population. and red raspberries, and blackberries Because of the cottontail’s reproduc- are the most frequently damaged Damage Prevention and tive potential, no lethal control is effec- food-producing woody plants, tive for more than a limited period. although cherry, plum, and nut trees Control Methods Control measures are most effective are also damaged. Exclusion when used against the breeding popu- Among shade and ornamental trees, lation during the winter. Habitat the hardest hit are mountain ash, bass- One of the best ways to protect a back- modification and exclusion techniques wood, red maple, sugar maple, honey yard garden or berry patch is to put up provide long-term, nonlethal control. locust, ironwood, red and white oak, a fence. It does not have to be tall or and willow. Sumac, rose, Japanese bar- especially sturdy. A fence of 2-foot (60- berry, dogwood, and some woody cm) chicken wire with the bottom tight

D-77 rabbits are abundant and food is in plants to be protected. Taste repellents short supply, only hardware cloth will protect only the parts of the plant they guarantee protection. Small mesh contact; new growth that emerges after (1/4-inch [0.6-cm]) hardware cloth also application is not protected. Heavy protects against mouse damage. rains may necessitate reapplication of some repellents. A dome or cage of chicken wire secured over a small flower bed will Mothballs or dried blood meal some- allow vulnerable plants such as tulips times keeps rabbits from damaging to get a good start before they are left small flower beds or garden plots. 18-20" unprotected. Place these substances among the Habitat Modification plants. Blood meal does not weather well, however. One form of natural control is manipu- Taste repellents are usually more effec- lation of the rabbits’ habitat. Although tive than odor repellents. The degree frequently overlooked, removing of efficacy, however, is highly variable, 2-3" brush piles, weed patches, dumps, depending on the behavior and num- stone piles, and other debris where ber of rabbits, and alternative foods rabbits live and hide can be an excel- available. When rabbits are abundant Fig. 5. A cylinder of hardware cloth or other lent way to manage rabbits. It is espe- wire mesh can protect trees from rabbit damage. and hungry, use other control tech- cially effective in suburban areas niques along with chemical repellents. where fewer suitable habitats are likely to be available. Vegetation control Toxicants to the ground or buried a few inches is along ditch banks or fence rows will sufficient. Be sure the mesh is 1 inch eliminate rabbit habitat in agricultural There are no toxicants or fumigants (2.5 cm) or smaller so that young rab- settings but is likely to have detrimen- registered for use against rabbits. Poi- bits will not be able to go through it. A tal effects on other species such as soning rabbits is not recommended. more substantial fence of welded wire, pheasants. Always weigh the conse- Since state pesticide registrations vary, chain link, or hog wire will keep rab- quences before carrying out any form check with your local Cooperative bits, pets, and children out of the gar- of habitat management. Extension Service or USDA-APHIS- den and can be used to trellis vine ADC office for information on repel- Repellents crops. The lower 1 1/2 to 2 feet (45 to lents or other new products available 60 cm) should be covered with small Several chemical repellents discourage for use in your area. mesh wire. A fence may seem costly, rabbit browsing. Always follow Trapping but with proper care it will last many exactly the directions for application years and provide relief from the con- on the container. Remember that some Trapping is the best way to remove stant aggravation of rabbit damage. repellents are poisonous and require rabbits in cities, parks, and suburban Inexpensive chicken wire can be safe storage and use. For best results, areas. The first step is to get a well- replaced every few years. use repellents and other damage built and well-designed live trap. Cylinders of 1/4-inch (0.6-cm) wire control methods at the first sign of Several excellent styles of commercial hardware cloth will protect valuable damage. live traps are available from garden centers, hardware stores, and seed young orchard trees or landscape Most repellents can be applied, like catalogs. Most commercial traps are plants (Fig. 5). The cylinders should paint, with a brush or sprayer. Many wire and last indefinitely with proper extend higher than a rabbit’s reach commercially available repellents con- care. Average cost is about $20 to $30. while standing on the expected snow tain the fungicide thiram and can be Live traps can often be rented from depth, and stand 1 to 2 inches (2.5 to 5 purchased in a ready-to-use form (see animal control offices or pest control cm) out from the tree trunk. Larger Supplies and Materials). mesh sizes, 1/2- to 3/4-inch (1.2- to companies. Some formerly recommended repel- 1.8-cm), can be used to reduce cost, An effective wooden box trap (Fig. 6) lents are no longer available. Most but be sure the cylinder stands far can be made. This type of trap has repellents are not designed to be used enough away from the tree trunk that proven itself in the field and has been on plants or plant parts destined for rabbits cannot eat through the holes. used in rabbit research by biologists. human consumption. Most rabbit Commercial tree guards or tree wrap For best results, follow the plan to the repellents are contact or taste repel- are another alternative. Several types letter because each detail has been lents that render the treated plant parts of paper wrap are available, but they carefully worked out. are designed for protection from sun distasteful. Mothballs are an example or other damage. Check with your of an area or odor repellent that repels Place traps where you know rabbits local garden center for advice. When by creating a noxious odor around the feed or rest. Keep traps near cover so

D-78 Bore 5 Nail Top view — Top board removed 1/2" holes in end. Top Wire Screw eye 8"

2" Screw Tripping wire 6" 9-gauge Screw Door eyes Treadle Bait nail Hinge detail

Drill hole so screw turns and countersink head. Bevel edges

Front view 24" Handle optional Screws for removable top Side View — Side board removed Bevel Door 8 1/2" Door Tripping wire Bait nail 11 1/2" 9-gauge Door 1/8" Clearance Screw closed eye

Treadle 16"

Flush to floor Treadle

9" 1/2" Pivot screw eyes Loose connection Pivot screw eyes 8-gauge screw eye treadle wire

Fig. 6. Plans for the Tom Butzen wooden box trap for rabbits. that rabbits won’t have to cross large Apples, carrots, cabbage, and other Shooting open areas to get to them. In winter, fresh green vegetables are good baits Shooting is a quick, easy, and effective face traps away from prevailing winds in warmer weather or climates. These method of control, but make sure that to keep snow and dry leaves from soft baits become mushy and ineffec- local firearms laws allow it and that it plugging the entrance or interfering tive once frozen. A good summer bait is done safely. In some states, the with the door. Check traps daily to re- for garden traps is a cabbage leaf owner or occupant of a parcel of land plenish bait or remove the catch— rolled tightly and held together by a may hunt rabbits all year on that land, daily checks are essential for effective toothpick. For best results, use baits except for a short time before the fire- control and for humane treatment of that are similar to what the target rab- arm deer season. Consult your state the animals. Move traps if they fail to bits are feeding on. wildlife agency for regulations. You make a catch within a week. A commercial wire trap can be made must be persistent if shooting is the Finding bait is not a problem, even in more effective (especially in winter) by only technique you rely on. Removing winter, because cob corn (dry ear corn) covering it with canvas or some other rabbits in one year never guarantees or dried apples make very good bait. dark material. Be sure the cover does that the rabbit population will be low Impale the bait on the nail or simply not interfere with the trap’s mecha- the next year (this is also true for position it at the rear of the trap (com- nism. trapping). mercial traps may not have a nail). Release rabbits in rural areas several When using cob corn, use half a cob Other Methods miles from where they have been and push the nail into the pith of the trapped if local regulations allow relo- Encouraging the rabbit’s natural cob; this keeps the cob off the floor and cation. Do not release them where they enemies—or at least not interfering visible from the open door. Dried leafy may create a problem for someone with them—may aid in reducing alfalfa and clover are also good cold- else. rabbit damage. Hawks, owls, foxes, weather baits.

D-79 mink, weasels, and snakes all help the ucts are readily available in garden For Additional farmer, gardener, homeowner, and centers and through mail order cata- Information forester control rabbits. These animals logues. Feeding rabbits during the should never be needlessly destroyed. winter in much the same way as Burt, W. H., and R. P. Grossenheider. 1976. A In fact, it is against the law to kill feeding wild birds might divert their field guide to the mammals, 3d ed. hawks and owls; foxes, mink, and attention from trees and shrubs and Houghton Mifflin Co., Boston. 289 pp. weasels are protected during certain thus reduce damage in some areas. Chapman, J. A., J. G. Hockman, and W. R. seasons as valuable furbearers. Even There is always the risk that this tactic Edwards. 1982. Cottontails. Pages 83-123 in J. A. Chapman and G. A. Feldhamer, eds. the family cat can be a very effective can backfire by drawing in greater Wild mammals of North America: biology, predator on young nestling rabbits, numbers of rabbits or increasing the management and economics. The Johns but cats are likely to kill other wildlife survival of those present. Hopkins Univ. Press, Baltimore. as well. Chapman, J. A., J. G. Hockman, and Magaly M. Ojeda C. 1980. Sylvilagus floridanus. Mammal. Many people have a favorite rabbit Acknowledgments Sp. 136:1-8. remedy. A piece of rubber hose on the ground may look enough like a snake I thank R. A. McCabe for reviewing this Jackson, H. H. T. 1961. The mammals of manuscript and providing the trap design. Wisconsin. Univ. Wisconsin Press, Madison. to scare rabbits away. Another remedy 504 pp. calls for placing large, clear glass jars Figure 1 from Schwartz and Schwartz (1981). McDonald, D. 1984. Lagomorphs. Pages 714-721 of water in a garden. Supposedly, Figures 2 and 3 adapted from Burt and in D. McDonald, ed. The encyclopedia of rabbits are terrified by their distorted Grossenheider (1976) by Dave Thornhill, mammals. Facts on File Publications, New reflections. Most home remedies, University of Nebraska-Lincoln. York. unfortunately, are not very effective. Figures 4 and 5 courtesy of the Department of Inflatable owls and snakes, eyespot Agricultural Journalism, University of balloons, and other commercial prod- Wisconsin-Madison. Editors Scott E. Hygnstrom Robert M. Timm Gary E. Larson

D-80 James E. Knight Extension Wildlife Specialist Animal and Range Sciences JACKRABBITS AND Montana State University Bozeman, Montana 59717 OTHER HARES

Fig. 1. Blacktail jackrabbit, Lepus californicus (left); whitetail jackrabbits, L. townsendii (middle); showshoe hare, L. americanus (right).

Damage Prevention and Frightening Trapping Control Methods Guard dogs. Body-gripping and leghold traps. Repellents Box traps. Exclusion Ammonium soaps, capsaicin, naphtha- Shooting Fencing. lene, thiram, tobacco dust, ziram. Spotlighting and day shooting are Tree trunk guards. Toxicants effective where legal. Cultural Methods Anticoagulants (where registered). Hunting. Manipulation of habitat. Fumigants Other Methods Planting of less desirable crops. None are registered. Predators.

Fig. 2. Range of the (a) whitetail jackrabbit, (b) blacktail jackrabbit, and (c) snowshoe hare.

Identification in size. This nonnative hare is brown- Where food and shelter are available ish gray year-round. in one place, no major daily movement Three major species of jackrabbits of hares occurs. When food areas and occur in North America (Fig. 1). These shelter areas are separated, morning hares are of the genus Lepus and are Range and evening movements may be represented primarily by the blacktail The whitetail jackrabbit is found observed. Daily movements of 1 to 2 jackrabbit, the whitetail jackrabbit, and mainly in the north central and north- miles (1.6 to 3.2 km) each way are the snowshoe hare. Other members of western United States and no further fairly common. In dry seasons, 10-mile this genus include the antelope jack- south than the extreme north central (16-km) round trips from desert to rabbit and the European hare. Hares part of New Mexico and southern alfalfa fields have been reported. have large, long ears, long legs, and a Kansas (Fig. 2a).The blacktail jack- larger body size than rabbits. rabbit is found mainly in the south- Damage The whitetail jackrabbit is the largest western United States and the hare in the Great Plains, having a head southern Great Plains, and no further Hares consume 1/2 to 1 pound (1.1 to and body length of 18 to 22 inches (46 north than central South Dakota and 2.2 kg) of green vegetation each day. to 56 cm) and weighing 5 to 10 pounds southern Washington (Fig. 2b). Snow- Significant damage occurs when hare (2.2 to 4.5 kg). It is brownish gray in shoe hares occupy the northern concentrations are attracted to summer and white or pale gray in regions of North America, including orchards, gardens, ornamentals, or winter. The entire tail is white. The Canada, Alaska, the northern conti- other agricultural crops. High jack- blacktail jackrabbit, somewhat smaller nental United States, and the higher rabbit populations can also damage than its northern cousin, weighs only 3 elevations as far south as New Mexico range vegetation. to 7 pounds (1.3 to 3.1 kg) and is 17 to (Fig. 2c). Antelope jackrabbits are Most damage to gardens, landscapes, 21 inches (43 to 53 cm) long. It has a found only in southern Arizona, New or agricultural crops occurs in areas grayish-brown body, large black- Mexico, and western Mexico. The adjacent to swamps or rangeland nor- tipped ears, and a black streak on the European hare is found only in south- mally used by hares. Damage may be top of its tail. The snowshoe hare is 13 ern Quebec, New York, and other temporary and usually occurs when to 18 inches (33 to 46 cm) long and New England states. natural vegetation is dry. Green vege- weighs 2 to 4 pounds (0.9 to 1.8 kg). It General Biology, tation may be severely damaged dur- has larger feet than the whitetail and ing these dry periods. blacktail jackrabbits. The snowshoe Reproduction, and turns white in winter and is a dark Behavior Orchards and ornamental trees and brown during the summer. Its ears are shrubs are usually damaged by smaller than those of the other hares. Members of the genus Lepus are born overbrowsing, girdling, and stripping The antelope jackrabbit is 19 to 21 well-furred and able to move about. of bark, especially by snowshoe hares. inches (48 to 53 cm) long and weighs 6 Little or no nest is prepared, although This type of damage is most common to 13 pounds (2.7 to 5.9 kg). Its ears are the young are kept hidden for 3 to 4 during winter in northern areas. extremely large and its sides are a pale days. Females may produce up to 4 Rangeland overbrowsing and over- white. The European hare is the largest litters per year with 2 to 8 young per grazing can occur any time jackrabbit of the hares in the Northeast, weighing litter. Reproductive rates may vary numbers are high. Eight jackrabbits are 7 to 10 pounds (3.1 to 4.5 kg) and from year to year depending on estimated to eat as much as one sheep, reaching 25 to 27 inches (63 to 68 cm) environmental conditions. and 41 jackrabbits as much as one cow. D-82 Estimates of jackrabbit populations gizers and high-tensile wire will mini- Repellents run as high as 400 jackrabbits per mize cost and maximize effectiveness. Since state pesticide registrations vary, square mile (154/km2) extending over Tree Trunk Guards. The use of indi- check with your local Cooperative several hundred square miles. Range vidual protectors to guard the trunks Extension or USDA-APHIS-ADC damage can be severe in such situa- of young trees or vines may also be office for information on repellents le- tions, especially where vegetation pro- considered a form of exclusion. gal in your area. ductivity is low. Among the best of these are cylinders Various chemical repellents are offered made from woven wire netting. as a means of reducing or preventing Legal Status Twelve- to 18-inch-wide (30.5- to 45.7- hare damage to trees, vines, or farm cm) strips of 1-inch (2.5-cm) mesh Jackrabbits are considered nongame and garden crops. Repellents make poultry netting can be formed into cyl- animals in most states and are not protected plants distasteful to jack- inders around trees. Cylinders should protected by state game laws. A few rabbits. A satisfactory repellent must be anchored with lath or steel rods and states protect jackrabbits through also be noninjurious to plants. regulations. Most states in which braced away from the trunk to prevent snowshoe hares occur have some rabbits from pressing them against the In the past, a variety of repellents have regulations protecting them. Consult trees and gnawing through them. been recommended in the form of paints, smears, or sprays. Many of local wildlife agencies to determine the Types of tree protectors commercially these afford only temporary protection legal status of the species before apply- available include aluminum, nylon and must be reapplied too often to ing controls. mesh wrapping, and treated jute card- warrant their use. Other, more per- board. Aluminum foil, or even ordi- sistent materials have caused injurious nary sacking, has been wrapped and Damage Prevention and effects to the treated plants. Some tied around trees with effective results. Control Methods chemical substances such as lime- Wrapping the bases of haystacks with sulphur, copper carbonate, and asphalt Exclusion 3-foot-high (0.9-m) poultry netting pro- emulsions have provided a certain Fencing. Exclusion is most often vides excellent protection. amount of protection and were harm- accomplished by the construction of less to the plants. These are less com- Cultural Methods fences and gates around the area to be monly used today and have been protected. Woven wire or poultry net- Habitat Manipulation. In areas replaced by various commercial prepa- ting should exclude all hares from the where jackrabbit or hare damage is rations such as ammonium soaps, cap- area to be protected. To be effective, likely to occur, highly preferred crops saicin, dried blood, napthalene, use wire mesh of less than 1 1/2 inches such as alfalfa, young cotton plants, thiram, tobacco dust, and ziram, (3.8 cm), 30 to 36 inches (76 to 91 cm) lettuce, and young grape vines are which are probably more effective. high, with at least the bottom 6 inches usually most damaged. Crops with Repellents are applied during either (15 cm) buried below ground level. large mature plants, such as corn, usu- the winter dormant season or summer Regular poultry netting made of 20- ally are not damaged once they grow growing season. Recommendations gauge wire can provide protection for beyond the seedling stage. Where pos- vary accordingly. 5 to 7 years or more. Although the ini- sible, avoid planting vulnerable crops Be sure to use repellents according to tial cost of fences appears high—about near historically high hare populations. the manufacturer’s guidelines and fol- $1,000 per mile ($625/km)—they are Overuse of range forage can some- low label recommendations. economically feasible for protecting times lead to high jackrabbit numbers. high-value crops and provide year- Powders. Any repellent applications Jackrabbits are least abundant where round protection on farms with a his- that involve the use of powders should grass grows best within their range. tory of jackrabbit problems. Remember be dusted on garden crops early in the Like many rodents, they prefer open to spread the initial cost over the morning when plants are covered with country with high visibility to areas expected life of the fence when com- dew, or immediately after a rain. Do where the grass prevents them from paring fencing with other methods. not touch plants with equipment or seeing far. Thus, control programs Exclusion by fencing is desirable for clothing because moist plants, espe- accompanied by changes in grazing small areas of high-value crops such as cially beans, are susceptible to disease. practices that encourage more vegeta- gardens, but is usually impractical and When a duster is not available and tive growth may be necessary for long- too expensive for larger acreages of only a few plants are involved, use a term relief. farmland. bag made of cheesecloth to sift repel- Frightening lent dust onto plant foliage. Repeated Electric fencing has been found to applications may be necessary after exclude jackrabbits. Six strands spaced Guard Dogs. Dogs can be chained rains have washed the powder from 3 inches (7.6 cm) apart alternating hot along boundaries of crop fields or near the foliage and as new plant growth and ground wires should provide a gardens to deter jackrabbits. takes place. deterrent to most hares. Modern ener-

D-83 Sprays. Thoroughly cover the upper by reducing the clotting ability of the target animals are present. Placement surfaces of the leaves with spray repel- blood and by causing damage to the of sticks 1 foot (0.3 m) above the trap lent. If a sprayer is unavailable and capillary blood vessels. Death is will encourage deer and other large only a small number of plants are caused only if the treated bait is con- animals to step over the trap while involved, a whisk broom or brush can sumed in sufficient quantities for allowing access to jackrabbits or other be used to apply the repellent to the several days. A single feeding on anti- hares. Be sure to check with local wild- plant foliage. The repellents will coagulant baits will not control life officials on the legality of trapping adhere to the foliage for a longer jackrabbits. Brodifacoum and broma- hares and jackrabbits. period if a latex-type adhesive is used. diolone may be exceptions, but they Shooting Reapply liquid repellents after a heavy are not yet registered for use on jack- rain and at 10-day intervals to make rabbits. Bait must be eaten at several Where safe and legal to do so, shooting certain new plant growth is protected. feedings on 5 or more successive days jackrabbits may suppress or eliminate with no periods longer than 48 hours Some repellents are not registered for damage. Effective control may be between feedings. application to leaves, stems, or fruits of achieved using a spotlight and a plants to be harvested for human use. When baiting with anticoagulants, use shooter in the open bed of a pickup A list of registered commercial repel- covered self-dispensing feeders or truck. Driving around borders of crop lents can be found in Supplies and nursery flats to facilitate bait consump- fields or within damaged range areas Materials. Many of these may be pur- tion and prevent spillage. Secure and carefully shooting jackrabbits can chased at a reasonable cost from sup- feeding stations so that they cannot remove a high percentage of the popu- pliers handling seed, insecticides, be turned over. Place 1 to 5 pounds lation. Some states require permits to hardware, and farm equipment. (0.5 to 2.5 kg) of bait in a covered self- shoot from vehicles or to use spot- dispensing feeder or nursery flat in lights. Commercial repellents containing runways, resting, or feeding areas that thiram are effective and can be applied In some states sport hunting of jack- are frequented by jackrabbits. Inspect safely to trees and shrubs. Treat all rabbits can be encouraged and may bait stations daily and add bait as stems and low branches to a point keep populations below problem needed. Acceptance may not occur un- higher than rabbits can reach while levels. til rabbits become accustomed to the standing on top of the estimated snow Other Methods feeder stations or nursery flats, which cover. One application made during a may take several days. When bait in Predators. Natural enemies of jack- warm, dry day in late fall should suf- the feeder is entirely consumed over- rabbits include hawks, owls, eagles, fice for the entire dormant season. night, increase the amount. It may be coyotes, bobcats, foxes, and weasels. Coal tar, pine tar, tar paper, and oils necessary to move feeders to different Control of these predators should have caused damage to young trees locations to achieve bait acceptance. occur only after taking into account under certain conditions. Carbolic acid Bait should be available until all feed- their beneficial effect on the reduction and other volatile compounds have ing ceases, which may take from 1 to 4 of jackrabbit populations. proved effective for only short periods. weeks. Replace moldy or old bait with For further information on repellents fresh bait. Pick up and dispose of baits and their availability, see Supplies upon completion of control programs. Economics of Damage and Materials. Dispose of poisoned rabbit carcasses and Control by deep burying or burning. Toxicants Jackrabbits consume considerable Since state pesticide registrations vary, Fumigants vegetation. In cases where their over- check with your local Cooperative use of natural forage results in the There are no fumigants registered for reduction of livestock on rangeland, Extension or USDA-APHIS-ADC jackrabbits. office for information on toxicants control measures may need to be legal in your area. Be sure to read the Trapping implemented. Few studies have been entire label. Use strictly in accordance conducted on the cost-effectiveness of with precautionary statements and Trapping with box-type traps is not ef- jackrabbit control on rangelands. Dam- directions. State and federal regula- fective because jackrabbits are reluc- age must be extreme to justify expen- tions also apply. tant to enter a trap or dark enclosure. ditures for control programs. In most Snowshoe hares are susceptible to box- cases, cultural controls and natural Anticoagulants. In areas where they type traps. mortality will suffice to keep jackrabbit are legal, anticoagulant baits may be populations in check. used to control jackrabbits. Varying Body-gripping and leghold traps can degrees of success have been reported be placed in rabbit runways. Trapping Economic loss on croplands is much with diphacinone, warfarin, brodi- in runways may result in unacceptable easier to measure. In areas with his- facoum, and bromadiolone. Antico- nontarget catches. Check for tracks in toric jackrabbit or hare damage, farm- agulants control jackrabbits and hares snow or dirt surfaces to be sure only ers should anticipate problems and

D-84 have materials available to use at the For Additional Palmer, T. S. 1987. Jackrabbits of the U.S. US Dep. Agric. Biol. Survey Bull. 8:1-88 first sign of damage. During dry times Information of the year or times of natural food Schwartz, C. W., and E. R. Schwartz. 1981. The shortages, preventive measures such Dunn, J. P., J. A. Chapman, and R. E. Marsh. wild mammals of Missouri. Univ. Missouri Press, Columbia. 356 pp. as shooting and exclusion may be con- 1982. Jackrabbits. Pages 124-145 in J. A. sidered a part of regular operations. Chapman and G. A. Feldhamer, eds. Wild Taylor W. P., C. T. Vorhies, and P. B. Lister 1935. mammals of North America: biology, The relation of jackrabbits to grazing in Jackrabbits and other hares can be de- management, and economics. The Johns southern Arizona. J. For. 33:490-493. terred most easily if control measures Hopkins Univ. Press, Baltimore. US Department of the Interior. 1973. Controlling are implemented before the hares Evans, J., P. L. Hegdal, and R. E. Griffith, Jr. rabbits. US Fish Wildl. Serv. Bull. 2 pp. become accustomed to or dependent 1982. Wire fencing for controlling jackrabbit Vorhies, C. T., and W. P. Taylor. 1933. The life on crops. damage. Univ. Idaho. Coop. Ext. Serv. Bull. No. 618. 7 pp. histories and ecology of jackrabbits, Lepus alleni and Lepus californicus sp. in relation to Johnston, J. C. 1978. Anticoagulant baiting for grazing in Arizona. Univ. Arizona Agric. Acknowledgments jackrabbit control. Proc. Vertebr. Pest Conf. Exp. Stn. Tech. Bull. 49:467-587. 8:152-153. Figure 1 of the snowshoe hare by Clint E. Lechleitner, R. R. 1958. Movements, density, and Chapman, University of Nebraska. mortality in a black-tailed jackrabbit Editors population. J. Wildl. Manage. 22:371-384. Figure 2 adapted by David Thornhill, from Burt Scott E. Hygnstrom and Grossenheider (1976). Robert M. Timm Gary E. Larson

D-85 D-86 Robert H. Schmidt Assistant Professor Department of Fisheries and Wildlife SHREWS Utah State University Logan, Utah 84322-5210

Fig. 1. A masked shrew, Sorex cinereus

Identification Damage Prevention and Fumigants The shrew is a small, mouse-sized Control Methods None are registered. mammal with an elongated snout, a Trapping dense fur of uniform color, small eyes, Exclusion and five clawed toes on each foot (Fig. Mouse trap (snap trap). Rodent-proof structures also exclude 1). Its skull, compared to that of shrews. Small box trap. rodents, is long, narrow, and lacks the zygomatic arch on the lateral side Cultural Methods Pit trap. characteristic of rodents. The teeth are Mowing may decrease preferred Shooting small, sharp, and commonly dark- tipped. Pigmentation on the tips of the habitat and food. Not practical. teeth is caused by deposition of iron in Repellents Other Methods the outer enamel. This deposition may None are registered. Cats may reduce densities around increase the teeth’s resistance to wear, Toxicants structures. Owls consume large an obvious advantage for permanent numbers of shrews. Mowed grass teeth that do not continue to grow in None are registered. around structures may increase response to wear. The house shrew predation. (Suncus murinus) lacks the pigmented teeth. Shrew feces are often corkscrew- shaped, and some shrews (for

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 D-87 Great Plains Agricultural Council Wildlife Committee example, the desert shrew [Notiosorex Food Habits venom in their saliva that may help crawfordi]) use regular defecation them subdue small prey. stations. Albino shrews occur occa- Shrews are in the taxonomic order Some shrews are mostly nocturnal; sionally. Shrews are similar to mice Insectivora. As the name implies, others are active throughout the day except that mice have four toes on insects make up a large portion of the and night. They frequently use the tun- their front feet, larger eyes, bicolored typical shrew diet. Food habit studies nels made by voles and moles. During fur, and lack an elongated snout. have revealed that shrews eat beetles, periods of occasional abundance, Moles also are similar to shrews, but grasshoppers, butterfly and moth lar- shrews may have a strong, although are usually larger and have enlarged vae, ichneumonid wasps, crickets, spi- temporary, negative impact on mouse front feet. Both shrews and moles are ders, snails, earthworms, slugs, or insect populations. Many predators insectivores, whereas mice are rodents. centipedes, and millipedes. Shrews kill shrews, but few actually eat them. Worldwide, over 250 species of shrews also eat small birds, mice, small Owls in particular consume large are recognized, with over 30 species snakes, and even other shrews when numbers of shrews. recognized in the United States, the US the opportunity presents itself. Seeds, Some shrews exhibit territorial behav- Territories, and Canada (Table 1). Spe- roots, and other vegetable matter are ior. Depending on the species and the cific identification of shrews may be also eaten by some species of shrews. habitat, shrews range in density from 2 difficult. Taxonomists are still refining to 70 individuals per acre (1 to 30/ the phylogenetic relationships between General Biology, hectare) in North America. populations of shrews. Consult a Reproduction, and regional reference book on mammals, Behavior or seek assistance from a qualified Damage mammalogist. Shrews are among the world’s small- Most species of shrews do not have est mammals. The pigmy shrew (Sorex significant negative impacts and are Range hoyi) is the smallest North American not abundant enough to be considered mammal. It can weigh as little as 0.1 pests (Schmidt 1984). Shrews some- Shrews are broadly distributed ounce (2 g). Because of their small size, times conflict with humans, however. throughout the world and North shrews have a proportionally high sur- The vagrant shrew (Sorex vagrans) has America. For specific range informa- face-to-volume ratio and lose body been reported to consume the seeds of tion, refer to one of the many refer- heat rapidly. Thus, to maintain a con- Douglas-fir (Pseudotsuga menziesii), ences available on mammal distribu- stant body temperature, they have a although the seeds constitute a minor tion for your region. Publications by high metabolic rate and need to con- part of the diet. The masked shrew Burt and Grossenheider (1976), Hall sume food as often as every 3 to 4 (Sorex cinereus) destroyed from 0.3% to (1981), and Junge and Hoffmann hours. Some shrews will consume 10.5% of white spruce (Picea glauca) (1981) are particularly helpful. three times their body weight in food seeds marked over a 6-year period over a 24-hour period. (Radvanyi 1970). Lodgepole pine Habitat Shrews usually do not live longer than (Pinus contorta) seeds are also eaten by 1 to 2 years, but they have 1 to 3 litters the masked shrew. Radvanyi (1966, Shrews vary widely in habitat prefer- per year with 2 to 10 young per litter. 1971) has published pictures of shrew, ences throughout North America. Specific demographic features vary mouse (Peromyscus, Microtus, and Shrews exist in practically all terres- with the species. The gestation period Clethrionomys spp.), and chipmunk trial habitats, from montane or boreal is approximately 21 days. (Eutamias spp.) damage to lodgepole regions to arid areas. The northern wa- pine seeds, and describes shrew dam- Shrews have an acute sense of touch, ter shrew (Sorex palustris) prefers age to white spruce seeds. marshy or semiaquatic areas. Regional hearing, and smell, with vision playing reference books will help identify spe- a relatively minor role. Some species of The northern water shrew (Sorex cific habitats. A word of caution is in shrews use a series of high-pitched palustris) may cause local damage by order, however. Distribution studies squeaks for echolocation, much as bats consuming eggs or small fish at hatch- based on the results of snap-trapping do. However, shrews probably use eries. The least shrew (Cryptotis parva), research have a pronounced tendency echolocation more for investigating also known as the bee shrew, some- to understate the abundance of their habitat than for searching out times enters hives and destroys the shrews. Studies using pit traps are food. Glands located on the hindquar- young brood (Jackson 1961). The more successful in assessing the pres- ters of shrews have a pungent odor northern short-tailed shrew (Blarina ence or absence of shrews in a particu- and probably function as sexual attrac- brevicauda) has been reported to dam- lar location. tants. Blarina brevicauda, and presum- age ginseng (Panax spp.) roots. Short- ably B. carolinensis and B. hylophaga tailed and masked shrews reportedly (the short-tailed shrews), have a toxic can climb trees where they can feed on

D-88 Table 1. Shrews of the United States, the US Territories, and Canada (from Legal Status Banks et al. 1987, and Jones et al. 1992). Shrews are not protected by federal Scientific name Common name laws, with one exception. The south- Blarina brevicauda Northern short-tailed shrew eastern shrew (Sorex longirostris fischeri) Blarina carolinensis Southern short-tailed shrew is protected in the Great Dismal Blarina hylophaga Elliot’s short-tailed shrew Swamp in Virginia and North Carolina Cryptotis parva Least shrew by the Endangered Species Act of Notiosorex crawfordi Desert shrew 1973. Nowak and Paradiso (1983:131) Sorex alaskanus Glacier Bay water shrew list the following additional species or Sorex arcticus Arctic shrew populations of concern: Sorex preblei, Sorex arizonae Arizona shrew Sorex trigonirostri, and Sorex merriami in Sorex bairdii Baird’s shrew Oregon; Sorex trigonirostri eionis in Sorex bendirii Pacific water or Marsh shrew Florida along the Homossassee River; Sorex cinereus Cinereus or Masked shrew and Sorex palustris punctulatus in the Sorex dispar Long-tailed or Rock shrew southern Appalachians. Sorex fontinalis Maryland or Eastern shrew Some states may have special regula- Sorex fumeus Smokey shrew tions regarding the collection or killing Sorex gaspensis Gaspe shrew of nongame mammals. Consult your Sorex haydeni Hayden’s shrew local wildlife agency or Cooperative Sorex (Microsorex) hoyi Pygmy shrew Extension office for up-to-date Sorex hydrodromus Pribilof Island shrew information. Sorex jacksoni St. Lawrence Island shrew Sorex longirostris Southeastern shrew Sorex lyelli Mt. Lyell shrew Damage Prevention and Sorex merriami Merriam’s shrew Control Methods Sorex monticolus Montane or Dusky shrew Sorex nanus Dwarf shrew Exclusion Sorex ornatus Ornate shrew Rodent-proofing will also exclude Sorex pacificus Pacific shrew shrews from entering structures. Place Sorex palustris Northern water shrew hardware cloth of 1/4-inch (0.6-cm) Sorex preblei Preble’s shrew mesh over potential entrances to Sorex sonomae Fog shrew exclude shrews. The pygmy shrew Sorex tenellus Inyo shrew (Sorex hoyi) may require a smaller Sorex trowbridgii Trowbridge’s shrew mesh. Coarse steel wool placed in Sorex tundrensis Tundra shrew small openings can also exclude Sorex ugyunak Barren ground shrew shrews. Sorex vagrans Vagrant shrew Suncus murinus House shrew Cultural Methods Regular mowing around structures should decrease preferred habitat and eggs or young birds in a nest or con- an introduced species to Guam. It has food, and may increase predation. sume suet in bird feeders. been reported as a host for the rat flea Where shrews are eating tree seeds, (Xenopsylla cheopis) which can carry the The pugnacious nature of shrews plant seedlings instead to eliminate plague bacillus (Yersinia pestis) sometimes makes them a nuisance damage. (Churchfield 1990). Compared to rat when they live in or near dwellings. (Rattus spp.) numbers, however, house Shrews occasionally fall into window Repellents shrew numbers are usually low, and wells, attack pets, attack birds or chip- risk of plague transmission is probably No repellents are registered for use munks at feeders, feed on stored minimal. The house shrew is accus- against shrews. foods, contaminate stored foods with tomed to living around humans and feces and urine, and bite humans when houses, which increases its damage Toxicants improperly handled. Potential exists potential. It is considered smelly and for the transmission of diseases and No toxicants are registered to poison noisy, making incessant, shrill, clatter- parasites, but this is poorly docu- shrews. ing sounds as it goes along (Church- mented. field 1990:149). On occasion it destroys The house shrew (Suncus murinus) is stored grain products.

D-89 Fumigants No fumigants are registered for use against shrews. It would be impractical to use fumigants because of the porous nature of typical shrew burrows.

Trapping Mouse traps (snap traps), box traps, a and pit traps have been used to collect shrews. Set mouse traps in runways or along walls, with the traps set at a right angle to the runway and the triggers placed over the runway (Fig. 2a). Small box traps can be set parallel to and inside of runways, or parallel to walls around structures (Fig. 2b). Bait the traps with a mixture of peanut butter and rolled oats. A small amount of bacon grease or hamburger may increase the attractiveness of the bait. A pit trap consists of a gallon jar or a large can sunk into the ground under a runway until the lip of the container is level with the runway itself (Fig. 2c). b Bait is not necessary. A small amount of bacon grease smeared around the top of the container may be an effective attractant, but this may also attract large scavengers. Pit traps are more effective for capturing shrews than snap traps, although the increased labor involved in setting a pit trap may not be justified when trying to capture only one or two animals. Monitor pit traps daily, preferably in the morning before the temperature gets hot, although Churchfield (1990) recom- mends checking traps four times in a 24-hour period. Place cotton wool in the pit trap containers to reduce the c mortality of trapped animals. This is especially important to ensure the successful release of nontarget animals. Since shrews are generally beneficial in consuming insects, live-captured animals can be relocated in suitable habitat more than 200 yards (193 m) from the capture site. The traps and placement procedures described above are also effective for catching mice. Note the identification Fig. 2. Traps and trap placement for capturing shrews: a) mouse trap (snap trap) set perpen- characteristics given above for deter- dicular to wall, with trigger next to wall; b) box mining whether the captured animal is trap set parallel to wall; c) pit trap sunk in indeed a shrew. Sometimes birds are ground over runway (includes cotton wool). captured in traps set for shrews. If this

D-90 occurs, try placing a cover over the that if a shrew ran across a farm ani- Chambers, K. A. 1979. A country-lover’s guide traps, a cover over the bait, moving the mal that was lying down, the animal to wildlife. The Johns Hopkins Univ. Press, Baltimore, Maryland 228 pp. traps to another location, or omitting would suffer intense pain. To counter- rolled oats from the bait mixture. act this, a shrew would be walled up Churchfield, S. 1990. The natural history of shrews. in an ash tree (a ‘shrew ash’), and then Cornell Univ. Press, Ithaca, New York. 178 pp. Shooting a twig taken from the tree would be Fowle, C. D., and R. Y. Edwards. 1955. An brushed onto the suffering animal to unusual abundance of short-tailed shrews, Shooting is not practical and is not rec- Blarina brevicauda. J. Mammal. 36:36-41. relieve the pain. The ancient Egyptians ommended. It is illegal in some states Hall, E. R. 1981. The mammals of North America. and localities. believed the shrew to be the spirit of darkness. The shrew has also been Vol. 1. John Wiley and Sons, New York. 690 pp. Other Methods mentioned as a Zuni beast god, pro- Hoffmeister, D. F. 1967. An unusual concentration viding protection for stored grains of shrews. J. Mammal. 48:462-464. Owls may reduce local populations of from raids by rats and mice Jackson, H.H.T. 1961. Mammals of Wisconsin. shrews in poor habitats, but this has (Hoffmeister 1967). Univ. Wisconsin Press, Madison. 504 pp. not been documented. Domestic cats Jones, J. K., Jr., R. S. Hoffmann, D. R. Rice, C. appear to be very good predators of At least one tall tale involving shrews Jones, R. J. Baker, and M. D. Engstrom. 1992. shrews, although they seldom eat has been found to be true. The discov- Revised checklist of North American them (presumably because of the ery that some shrews possess a toxic mammals north of Mexico, 1991. Occas. Papers Mus. Texas Tech Univ. 146:1-23. shrew’s unpleasant odor). Cats may be venom confirms stories about the effective at temporarily reducing local- poisonous bite of shrews. Junge, J. A., and R. S. Hoffmann. 1981. An annotated key to the long-tailed shrews ized shrew populations living in poor The etymology of the word shrew is (genus Sorex) of the United States and cover around structures. Cat owners also interesting. The Old English form Canada, with notes on Middle American may find dead, uneaten shrews of the word was screawa, or shrew- Sorex. Univ. Kansas, Mus. Nat. Hist., Occas. brought inside the home. Rather than mouse. The Middle English form was Papers 94:1-48. reduce the shrew population outside shrewe, meaning an evil or scolding Martin, I. G. 1981. Venom of the short-tailed to prevent this, simply monitor loca- person. Thus shrew has a double shrew (Blarina brevicauda) as an insect immobilizing agent. J. Mammal. 62:189-192. tions regularly used by your cat, and meaning. It defines the small mammal dispose of dead shrews by placing a as well as an ill-tempered, scolding hu- Nowak, R. M., and J. L. Paradiso. 1983. Walker’s plastic bag over your hand, picking up mammals of the world. Vol. 1. The Johns man (usually female). Hopkins Univ. Press, Baltimore, Maryland. the dead animal, turning the bag 568 pp. inside out while holding the shrew, Shrews are in the family Soricidae. sealing the bag, and discarding it with Soricis is the genitive form of sorex, a Radvanyi, A. 1966. Destruction of radio-tagged Latin word for shrew-mouse. seeds of white spruce by small mammals the garbage. Using a plastic bag in this during summer months. For. Sci. 12:307-315. manner reduces the potential for flea, Radvanyi, A. 1970. Small mammals and tick, helminth parasite, or disease Acknowledgments regeneration of white spruce forests in transmission. western Alberta. Ecol. 51:1102-1105. I appreciate the assistance and comments of C. Radvanyi, A. 1971. Lodgepole pine seed Economics of Damage L. Shugart, S. E. Hygnstrom, and four anony- depredation by small mammals in western mous reviewers while developing this manu- Alberta. For. Sci. 17:213-217. and Control script. L. Thomas and J. Shepard provided up-to-date information on the legal status of Schmidt, R. H. 1984. Shrew damage and control: Sorex longirostris fischeri. a review. Proc. Eastern Wildl. Damage No studies concerning the economics Control Conf. 1:143-146. Figure 1 is reproduced with permission from of shrew damage and control are avail- Schwartz and Schwartz (1981). Schwartz, C. W., and E. R. Schwartz. 1981. The able. In Finland, shrews appear to play wild mammals of Missouri, rev. ed. Univ. a more important role as predators of Figure 2 was drawn by Jill Sack Johnson. Missouri Press, Columbia. 356 pp. conifer seeds than they do in North Tomasi, T. E. 1979. Echolocation by the short- America. Overall, the economics of For Additional tailed shrew Blarina brevicauda. J. Mammal. 60:751-759. damage by shrews is not considered Information great. Banks, R. C., R. W. McDiarmid, and A. L. Gardner, eds. 1987. Checklist of vertebrates Folklore and Etymology of the United States, the US Territories, and Editors Canada. US Dep. Inter, Fish Wildl. Serv., Scott E. Hygnstrom Chambers (1979) reviewed some Resour. Pub. 166. 79 pp. Robert M. Timm Gary E. Larson aspects of shrew biology and folklore: Burt, W. H., and R. P. Grossenheider. 1976. A At one time in Europe it was thought field guide to the mammals. Houghton Mifflin Co., Boston. 289 pp.

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