GUESS WHO’S COMING TO DINNER?

Pest management professionals are seeing an increase of calls regarding nuisance wildlife animals. Here’s how to deal with these new urban pests.

Aren’t they elegant! If my wife has said this once, she’s said it a dozen times when fawns (“Bambis”) and their mothers wander into our yard — until they begin to nibble her hostas and azaleas. Then she becomes a raving lunatic, looking for any weapon as she tears down the driveway screaming, “Get out of my yard!”

While they are cute, as is the case for most urban wildlife, it has been estimated that deer cause $1 billion in damage to agricultural crops, forests and structural landscapes. This problem worsens as natural habitats of these animals are suburbanized.

It is unfortunate that most suburbanites fail to appreciate the dilemma facing these animals. Confrontations with humans generally are the result of the animals seeking shelter and food. For example, raccoons, unable to distinguish an attic or chimney from a tree hole, see it as a warm and protected area to nest. Likewise, deer see landscape plants as a source of tender food.

Urban wildlife populations are growing by leaps and bounds because their natural predators, less tolerant of the human interface, have moved on. Human predation by hunting, which once assisted in reducing deer populations, typically is not allowed within suburbanized areas and deer know it. About the only remaining predators for urban wildlife are motor vehicles. Thus, pest management professionals are frequently asked to address these problems and assist their customers in doing so.

This article is designed to provide an overview of the problems associated with three urban neighbors: deer, raccoons and woodchucks (ground hogs), as well as present some strategies for dealing with them. It will focus on preventive strategies and non-lethal ways of protecting structures and their landscapes. I am not an advocate of killing any wildlife.

DEER. There are three types of deer within the United States: white-tailed deer are found throughout the U.S. and Canada; mule deer are in western states and Canada; and, black-tailed deer are found only on the West Coast.

Breeding takes place in the fall and is heaviest in November. Most fawns are born in May or June. A young doe typically has a single birth, whereas a mature doe typically has twins.

Large bucks can weigh as much as 200 to 300 pounds; does are about 120 to 180 pounds. While some live longer, the average life span is 10 to 12 years. Deer are herbivores, typically feeding on the tender foliage of woody plants in the early morning and evening. One of their major staples is nuts, especially acorns. They readily feed on the corn, vegetables and fruits in agricultural fields, as well as in backyard gardens.

Several problems are associated with deer: The most common problem is depredation of structural landscape plants, gardens and trees. In some cases, the damage can be so severe that the plants do not recover. Deer are one of the most significant host animals for Ixodes scapularis and Ixodes pacificus ticks, both vectors of Lyme disease.

Except for relatively short hunting seasons, deer are protected animals within the U.S. and Canada. Thus, lethal methods of control cannot be used unless special exceptions are granted by the local state wildlife agency. In some jurisdictions, local hunts “out of season” have been permitted to reduce herd size. These hunts usually take place on state and/or county property. In some situations where deer damage is severe, local neighborhoods have hired bow hunters to thin deer herds.

As professionals, our options for deer control are limited and typically involve making recommendations to customers. The following strategies may prove useful in deterring deer activity and reducing damage.

Exclusion: Fencing can be used to prevent deer from entering an area.

Temporary electric fences are inexpensive and can be used to protect small gardens and landscaped areas.

A peanut butter fence, which involves placing peanut butter on aluminum foil flags fastened on a single strand of wire, is a more permanent solution for larger areas. When the deer lick the peanut butter, they are shocked and soon learn to avoid the area.

More permanent, elaborate electric fences can cost more than $0.35 per foot to install and require weekly maintenance.

Permanent non-electric fencing can also be installed; however, this may be cost-prohibitive, usually $2 to $4 per linear foot. To exclude deer, fences should be 6½ to 10 feet high. Two styles include the slanted seven-wire deer fence and permanent woven wire fencing. If fencing is a consideration, only the best materials and, in most cases, a professional installer, should be used.

A less expensive option for protecting smaller plants is deer netting, which is not obtrusive. Deer netting is effective when used as a double barrier and sloped at an angle away from the protected area. The netting should be at least 18 inches from the plants so that deer can’t push on the fence and reach the plant.

A new exclusion device from Woodstream Corporation consists of a small battery-operated shocking device that uses an acorn attractant which is mounted on the end of a stake. This device should be installed near the plants to be protected; the number and spacing of the devices is best determined by experience. As the deer approach the area, they are attracted to the acorn odor, but as they lick the device, they receive a shock.

Cultural Practices: This involves the use of landscape plants that do not attract deer. Homeowners can receive this information from local extension agents and nurseries.

Frightening: This strategy is most effective when deer first venture into the area to be protected. Gas exploders, firecrackers and other noise-making devices can be effective in chasing deer away. Every few days, the location of the devices and the time at which they are used should be changed. Otherwise, deer will become accustomed to the noise and ignore it. Some jurisdictions do not permit the use of pyrotechnics. Dogs also can be used to frighten deer. It is best to confine the dog to the area to be protected by using an invisible fence rather than allowing the free-running dog to chase the deer.

Repellents: Because of their high cost and the need for periodic re-application, repellents are used for only limited areas. Two types of repellents include contact and area repellents.

Contact repellents, which typically contain bittering agents, are applied to plants, shrubs and trees, in the dormant season. Entire young trees should be treated, whereas only the new growth on mature trees requires treatment. Several commercial sprays are available. Home remedies, e.g., pepper spray and hot sauce, are only somewhat effective.

Area repellents are materials that are applied around the plants; their odor is designed to repel the deer. One or two commercial products and a couple of home remedies, e.g., human hair suspended in air penetrable bags and bars of soap suspended around plants to be protected, are available.

Options for controlling deer are limited. The most effective strategies, i.e., fencing and netting, often are aesthetically unacceptable. Killing offers an effective solution but generates significant hostility on both sides of the fence. The trick is to find some middle ground that will minimize their damage.

RACCOONS. Raccoons are readily recognized by their black masked face and ringed tail. The body fur is gray to black; however, some have more of a brown cast. They are about 2 to 3 feet long (including the tail) and typically weigh 10 to 30 pounds. They are found throughout most of the U.S. and southern Canada but are more prevalent in the eastern U.S.

Raccoons mate in winter. Their gestation period is 63 days and there is one litter per year that consists of three to five young, usually born in April or May. The young raccoons are weaned at two to four months. The majority of populations consist of one-year-olds. Occasionally, raccoons can live as long as 12 years.

Raccoons are nocturnal animals, venturing out only at night. It usually is an indication that it is a sick animal, possibly with rabies, if a raccoon is out during the day. The range of activity for males is 3 to 20 square miles and because they are territorial, their ranges rarely overlap. The range for females is 1 to 6 square miles. Raccoons do not hibernate but may undergo periods of inactivity, particularly during cold winter months.

Raccoons in urban environments present several potential problems, the most significant of which is that infection with rabies can result in both unusual behavior and the possibility of (humans and domestic animals) being bitten. (I suspect that a raccoon took the leg off of our cat, now named Trio, when it was a kitten.) In addition, most raccoons are infected with roundworms which, when ingested by other animals and humans, can cause a rare condition, i.e., visceral larva migrans. Roundworm eggs can be inhaled or ingested by contact with raccoon feces. Thus, a respirator, gloves and disinfectant should be used when dealing with raccoon droppings.

Raccoons can also cause significant damage when they construct dens in chimneys, crawlspaces and attics. They may rip up turf areas to get at grubs just below the soil surface. Raccoons are omnivores. In addition to a variety of fruits and vegetables from the home garden, raccoons feed on grains, nuts and fish in outdoor ponds. Their animal foods consist of frogs, clams, fish, small rodents, eggs and young ground-nesting birds. Dog and cat food left outside at night is one of the greatest attractants for raccoons.

Exclusion: Raccoons can be excluded from garden areas and other locations by using electric fencing (albeit on a smaller scale than discussed under deer exclusion) and netting. Wire fencing should be buried at least 12 inches under the ground and may need to be topped with an electric wire to prevent entry. Fishponds can be protected using electric fencing and netting.

Tree limbs should be trimmed from the house so that raccoons cannot climb on the roof. Alternatively, trees can be banded with 24-inch wide sheet metal that also can be used to protect fruit trees from depredation.

Cultural Changes: Changing cultural practices that entice raccoons into urban areas is the most effective way of preventing unwanted encounters with these enterprising animals. They should not intentionally or unintentionally be fed by humans, e.g., by leaving pet food out. Pets should be fed indoors and their food should be stored in areas secure from raccoon entry. Meats and their by-products should not be placed in compost piles. Garbage should be placed in containers and areas inaccessible to raccoons.

Occasionally raccoons enter structures through exterior pet doors, only to surprise the homeowner coming down to the kitchen for a midnight snack. Exterior pet doors should be secured at night or have an electronically activated locking mechanism.

To prevent raccoon denning in the house, chimneys should be capped, crawlspace vents and entryways should be sealed with heavy gauge hardware cloth, and attic entryways and vents should be sealed to prevent entry.

When excluding raccoons, they should be removed from the area prior to securing it. Sometimes they can be driven out by using mothballs, ammonia or other repellent materials. Regardless of how they are removed, ensure that young raccoons are not trapped inside, a most likely occurrence in the summer when they are only a few months old.

Frightening: Frightening raccoons is rarely successful as they are not intimidated by the presence of people or small domestic animals and readily return to areas which offer them food and shelter.

Repellents: Repellent materials, such as cayenne pepper, mothballs and ammonia, have not been shown to be very effective but may enhance the effectiveness of exclusion techniques.

Trapping: Trapping is one of the most effective methods of removing raccoons. Sturdy single-door wire traps (10 by 12 by 32 inches) are the most effective live animal traps. The end of the trap where the bait is placed should be covered with screen to prevent the raccoon from reaching in and stealing the bait. Raccoons are easy to trap using baits, such as cat food, sardines, chicken and fish. Once I caught three raccoons (a mother and two juveniles) in one trap.

The dilemma of live trapping is what to do with the raccoon once it is caught. In an effort to prevent the spread of rabies, many states prohibit the relocation and release of raccoons. Usually, trapped raccoons can be turned over to local animal shelters for disposition, unfortunately, usually euthanasia. Before trapping, check with local wildlife agencies regarding proper ways to handle trapped raccoons. One of the most practical solutions is to trap the raccoon, make cultural changes, secure areas from entry and release the raccoon on site. When transporting a live animal, cover the trap with burlap to keep the animal cool and calm and place plastic under the cage in your vehicle to prevent contamination with feces and urine. (You’ll only ignore this recommendation once!)

Lethal trapping techniques using leg hold traps and body-gripping traps are used in some situations. Many states consider raccoons protected fur-bearing animals that can only be taken during certain seasons. Many people consider these devices cruel and can generate a lot of adverse publicity when used.

Another lethal technique is shooting; however, the nocturnal habits of raccoons make this more difficult. Furthermore, as previously discussed, killing is regulated by local and state game laws and is not permitted in most urban areas.

Prevention of problems with raccoons is the most effective way of dealing with them. If we do not offer them food and harborage, they will move on.

WOODCHUCKS. Woodchucks (also called ground hogs or whistle pigs) are members of the squirrel family. They have a chunky body and dirty brown fur. Their legs are short and their front legs have long claws that are adapted for digging. Woodchucks have short furry tails and are 16 to 20 inches long and weigh 5 to 10 pounds. They are found within the eastern and midwestern U.S. throughout Canada up into Alaska.

Woodchucks mate during the spring and there is one litter per year with two to six young usually born in April or May. The young are weaned by late June or early July. The life span of a woodchuck is three to six years.

Woodchucks are active throughout the day, although most feeding occurs
in early morning and evening hours. Their range of activity, usually no more than 50 to 150 feet from their den, can be much greater when food is scarce and when males are seeking a mate. Woodchucks undergo true hibernation as early as late October and as late as early March.

Although woodchucks are less damaging than deer and raccoons, they create their own special problems, perhaps the greatest is their burrowing activity. Burrows are as deep as 5 feet and range from 8 to 66 feet in length. Typically, there are two or more openings to the den with the actual nesting site being deep within the burrow. This burrowing activity can undermine building foundations, injure livestock and people, and damage farm equipment. Burrowing frequently damages underground utilities and water supply lines.

Woodchucks are herbivores, preferring to feed on vegetables, grasses, soybeans, peas, alfalfa and clover. They find the residential garden an ideal feeding trough and readily consume vegetables there. They frequently claw at fruit trees and ornamentals, causing extensive damage.

Exclusion: Woodchucks are excellent climbers and diggers; these factors must be taken into consideration when trying to exclude them. They can be excluded from garden areas and other locations by using wire fencing (holes no larger than 2 inches), which should be buried at 10 to 12 inches under the ground and extend up 3 to 4 feet. Bending the top of the fence out at a 45o angle also prevents climbing. An electric wire should be placed 4 to 5 inches above the ground and the same distance away from the fence. In some cases a single electric wire, 4 to 5 inches off the ground, keeps them out of a garden.

Cultural Changes: There is little that can be done culturally to discourage foraging and burrowing by woodchucks.

Frightening: Frightening woodchucks rarely is successful. They are only temporarily intimidated by the presence of humans and domestic animals and hide in their burrow until the danger has passed, then readily return to areas that offer them food.

Repellents: There are no repellent materials and toxicants registered for woodchuck control. Most feeding deterrents cannot be applied to edible crops; thus, there is nothing that will discourage feeding on garden plants.

Trapping: Trapping is one of the most effective methods of removing woodchucks. Sturdy single-door wire traps (10 by 12 by 32 inches) are the most effective live animal traps. The end of the trap (where bait is placed) should be covered with screen to prevent the woodchuck from stealing the bait. They are easy to trap using baits, such as apples and fresh lettuce.

Typically, there are no state or local laws that prohibit the relocation of woodchucks. However, it is better to be safe than sorry, so check with your local wildlife agency regarding the disposition of trapped animals. When transporting a live animal, cover the trap with burlap to keep the animal cool and calm and place plastic under the cage in your vehicle to prevent contamination with feces and urine.

Lethal trapping techniques using leg hold traps and body-gripping traps are used in some situations. Keep in mind that many states may have regulations regarding the use of these traps. Many people consider these trapping devices cruel and can generate a lot of adverse publicity when they are used.

Exclusion and trapping are most effective in dealing with woodchucks. If burrows are not filled in (you can use rocks and dirt to pack in the burrow), other woodchucks or other animals soon occupy the burrow.

Lethal Techniques: Woodchucks can be killed by using smoke bombs (carbon monoxide) or aluminum phosphide (phosphine gas). In either case, the strategy is the same, i.e., seal all but the largest burrow entrance, introduce the fumigant, seal the main entrance and wait. If you do not see the animal enter the burrow during the day, this technique is best accomplished at night after they have returned to their burrows. Both gases are toxic to humans and domestic animals and should not be used near occupied structures. Use caution with smoke bombs because they are a fire hazard during dry weather conditions.

Another lethal technique is shooting; however, as previously discussed, killing is regulated and is not permitted in most urban areas.

CONCLUSION. As urbanization spreads into farmlands and forests, confrontations with wild animals will continue. I hope we can minimize conflicts by changing our cultural practices and finding ways to keep them out of areas we want to protect.

The author is technical director of American Pest Management, Takoma Park, Md. He can be reached at rkramer@pctonline.com.