Prepared by Candace J. Cummings, Extension Wildlife Associate, Clemson University. (New 08/99.)
All animals need food, water and shelter to survive and reproduce. If any of these are in short supply, animal numbers decline proportionately. On the other hand, when these requirements are met, the animal population will reproduce and increase in numbers, remaining stable until the supply of one requirement becomes limiting.
In situations where wildlife species become troublesome or compete with man’s economic or health interests, the animals are called pests. Many wildlife species coexist with humans very successfully. In fact, some, like the common rat and mouse, have become more or less dependent on people.
Most wildlife species have the potential of becoming pests. Whether or not a species becomes a pest can be directly correlated to the degree at which that animal can be tolerated. For many people, squirrels feeding in their yards or gardens is not a problem; while at the same time, a neighbor may feel the squirrels are a complete nuisance. Common wildlife pests in South Carolina include squirrels, bats, skunks, snakes, moles, voles, deer, rats/mice, chipmunks and groundhogs.
Wildlife species are usually only pests in certain situations, such as when their numbers become excessive in a particular area. Human change in the environment will often result in increased numbers of a species. For example, piles of scrap building material make excellent sites for rodents or snakes to frequent. Food left out for household pets is often equally attractive to some wildlife species. In these situations, the wildlife have suitable food and habitat and will usually become a nuisance.
The primary objective of any control program should be to reduce damage in a practical, humane and environmentally acceptable manner. If you base control methods on the habits and biology of the animals causing damage, your efforts will be more effective and will serve to maximize safety to the environment, humans and other animals.
A key to controlling wildlife damage is prompt and accurate determination of which animal is causing the damage. Even someone with no training or experience can often identify the pest by thoroughly examining the damaged area. Because feeding indications of many wildlife species are similar, other signs – such as droppings, tracks, burrows, nests or food caches – are usually needed to make a positive species identification.
After you properly identify the wildlife pest, you can choose control methods appropriate to the animal species involved. Improper control methods may harm but not kill the animal, causing it to become leery of those and other methods in the future. For example, using traps and poison baits improperly or in the wrong situation may teach the animal that the control method is harmful. This may make the animal difficult to control later, even with the correct method. Four steps lead to a successful nuisance wildlife control program:
The most commonly used methods for controlling nuisance wildlife around homes and gardens include exclusion, habitat modification, repellents, toxic baits, glue boards, traps and frightening.
Physically excluding an offending animal from the area being damaged or disturbed is the best and most permanent way to control the problem. Depending upon size of the area to be excluded, this control method can range from inexpensive to prohibitively costly. For example, damage by birds or rabbits to ornamental shrubs or garden plants can be reduced fairly inexpensively by simply placing netting over the plant(s) to keep the pests away. On the other hand, fencing out deer from a lawn or garden can be costly. Materials needed for exclusion will depend upon the species causing the problem. Large mammals can be excluded with woven wire fences, electric fences and poly-tape fences. Small mammals and some birds can be excluded with netting, tarp, hardware cloth or any other suitable material.
Modifying an animal’s habitat often provides lasting and cost-effective relief from damage caused by nuisance wildlife. Habitat modification is effective because it limits access to one or more of the requirements for life – food, water or shelter. Rodent- or bat-proofing buildings by sealing cracks and holes prevents these animals from gaining access to suitable habitats. Storing seed and pet food in tightly closed containers, controlling weeds and garden debris around homes and buildings, and storing firewood and building supplies on racks or pallets above ground level are also practices that can limit or remove the animals’ sources of food, water or shelter. However, habitat modification, while limiting nuisance wildlife, may also limit desirable species such as songbirds as well.
Using a method such as a repellent that changes the behavior of an animal may lead to a reduction or elimination of damage. Several available repellents, such as objectionable-tasting coatings or odor repellents, may deter wildlife from feeding on plants. Other repellents such as sticky, tacky substances placed on or near windows, trees or buildings may deter many birds and small mammals. Unfortunately, most wildlife soon discover that repellents are not actually harmful, and the animals may soon become accustomed to the smell, taste or feel of these deterrents. Repellents applied outdoors will have to be reapplied due to rain or heavy dew or applied often to new plant growth to be effective.
Methods such as toxic baits may be necessary to reduce nuisance wildlife numbers. The Department of Pesticide Regulation can provide information on products available in South Carolina. There are several types of toxicants available for use. Not all toxicants are labeled for certain species. Most products identified as "baits" are formulations which are designed to be consumed by the target animal. Some pesticides are in a gas form known as fumigants. "Restricted Use Pesticides" are products which may be used only by persons who have been trained and certified to use them due to the products’ highly toxic nature.
Glue boards and traps can be either a lethal or non-lethal method of control. Glue boards can be used to trap small mammals and snakes. Applying vegetable oil to the caught animal will dissolve the glue allowing for release of the animal. Using traps can be very effective in reducing actual population numbers of certain species. However, many species cannot be trapped without a permit. In most cases, homeowners may trap an offending animal within 100 yards of their residence without a permit.
Traditional live traps such as cage or box traps are easily purchased at most garden centers. These traps allow for safe release of the trapped animal. State law may prohibit the release of the animal to another area. Check with the South Carolina Department of Natural Resources for regulations. Leghold traps allow for either release or euthanasia of the trapped animal. Traps such as body-gripping traps, scissor and harpoon traps, as well as rat/mice snap traps, are nearly always lethal. Knowledge of trapping techniques is essential for a successful trapping program.
Frightening devices such as bells, whistles, horns, clappers, sonic emitters, audio tapes and other sound devices may be quite successful in the short term in repelling an animal from an area. Other objects such as effigies, lights, reflectors and windmills rely on visual stimulation to scare a problem animal away. Often nuisance animals become accustomed to these tactics and will return later if exposed to these devices daily.
Local retail outlets, such as farm and garden supply stores, hardware stores and nurseries, often stock pest control supplies. Federal and state agencies may also distribute materials on control methods as well as maintain lists of professionals who will do nuisance wildlife work for a fee.
Additional information about controlling specific nuisance wildlife species can be found in the Georgia Pest Management Handbook and on the website, Internet Center for Wildlife Damage Management.
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This information is supplied with the understanding that no discrimination is intended and no endorsement of brand names or registered trademarks by the Clemson University Cooperative Extension Service is implied, nor is any discrimination intended by the exclusion of products or manufacturers not named. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.