Beasts Begone! Removing Animals
Animal Removal Techniques
Below are descriptions of some of the legal methods commonly used to remove animals that enter buildings in New York State. Generally, a combination of methods will give better results than any one approach by itself. A list of suppliers and manufacturers is provided in Appendix D.
Live traps capture animals without killing them. Some types of live traps are box traps, multiple capture traps, and a variety of bird traps. By definition, foothold traps (commonly used in fur trapping) are live traps. However, foothold traps generally are not practical for removing animals from buildings.
Box traps capture animals that step upon a treadle inside the trap. The tripped treadle results in the closing of a door(s) at the end(s) of the trap. Many designs and sizes of box traps are available, especially for the capture of mammals. Usually the animal is enticed into the trap by a bait or lure. Some models with doors on opposite ends of the trap can capture animals that are simply passing through.
Multiple capture traps are able to catch more than one animal without having to be reset. Most multiple capture traps are designed for mice. Some brands (such as Ketch-All®) will catch animals up to the size of chipmunks. However, larger animals are more likely to suffer harm. Some designs (such as Ketch-All® and Kwick Katch®) have a wind-up spring that powers a rotating mechanism. When triggered, the mechanism entraps mice in a holding compartment. Other traps (notably the Victor Tin Cat®) have one-way doors that allow mice to enter but not exit.
Bird live traps are available in many varieties. Most are designed to capture particular types of birds, such as pigeons or sparrows. Some will capture one bird at a time, while others are multiple capture traps.
Lethal traps kill an animal upon capture, usually by means of a mechanical blow. The best known examples are mouse-and rat snap-back traps. Other designs and sizes exist for capturing a wide range of animals, especially mammals. One example is the ConibearTM, body gripping trap. Exercise extra caution when determining when and where lethal traps are set.
Glue boards or traps consist of a layer of long-lasting adhesive spread over a surface (usually plastic or cardboard). They effectively capture small animals by entrapping them in adhesive. If the animal is removed soon after capture, a glue board functions as a live trap. The animal can be removed by loosening the adhesive with vegetable oil. In practice, however, animals are frequently left to die on the glue boards. Thus, many people consider glueboards to be inhumane.
Passive nets are set in a location and left for a period of time. Animals are captured when they encounter the net and become entangled. Fine-threaded nets, known as mist nets, are often used to capture birds inside buildings.
There are several types of equipment used to facilitate the capture of animals without the use of traps.
Animal handling gloves. Various specialized gloves exist to protect operators while they are capturing an animal. The best designs cover not only the hand but also a portion of the arm. They are usually made of thick leather and may contain other materials, such as KevlarTM (from which bulletproof vests are made).
Hand-operated devices. Among the most versatile of hand-operated devices are catchpoles (control loops) that tighten a looped cable around the body of an animal. Other devices utilize vise-grip mechanisms to capture and restrain animals.
Nets also can be used for direct capture. Two designs are the throw net and "hoop" net. Throw nets are tossed over the target animal. "Hoop" nets (such as fish landing nets) are attached to the end of a long handle.
Disposing of Captured Animals
There are several options for disposing of an animal once it has been captured directly or with the use of live traps.
Releasing the captured animal just outside the building results in the least stress on the animal. This is most practical when an animal has incidentally entered the structure and there is little risk to humans in having the animal in the general vicinity of the building. A squirrel or bird that has fallen down a chimney is a good example. Releasing on-site is not a good idea if the presence of the animal (e.g., a Norway rat) involves significant health or safety risks. Combine on-site release with effective exclusion techniques to prevent the animal from reentering the building.
Relocation of a captured animal is a common but controversial technique. While solving some of the problems associated with releasing the animal on-site, there are legal and biological concerns with this practice. In New York State, moving a "protected" animal off property requires a nuisance wildlife control permit. You must also adhere to any trespass laws at the release site. Some specialists question the wisdom of relocating animals. There is evidence that stress and mortality rates increase when animals are released in unfamiliar territory. Relocated animals may harm resident animals (e.g., by fighting, disease transmission, gene pool disruptions, etc.) or cause problems for humans in the vicinity of the release site.
Euthanasia is a third option. By definition, euthanasia (or "good death") is more than simply killing the animal. The American Veterinary Medical Association's 1993 Report on Euthanasia, while dealing primarily with domestic animals, offers the most widely accepted guidelines for euthanasia practices.
Visual. There are many types of visual repellents for birds. They range in price and sophistication from simple inflatable plastic balls with large eyespots to mechanical human effigies. The repellent effect is generally immediate but short term. Movement of the devices increases effectiveness, especially if the movement is unpredictable or irregular.
Auditory. There are many types of auditory repellents for birds. The most effective are devices that play distress calls of the target species. Other types of auditory repellents utilize loud noises to startle the target. One example is a "shell cracker," a projectile (fired from a shotgun) that explodes in the air. Devices that claim to repel animals by use of ultrasonic waves not audible to humans have consistently proven to be ineffective.
Taste. Most bad-tasting repellents have been developed to deter deer or geese from damaging garden plants or lawns. Few taste repellents have been specifically designed for use on buildings. BitrexTM, one such substance, may help prevent chewing damage on the sides of buildings.
Olfactory. Products containing substances such as naphthalene or dried blood are known to have a repellent effect, particularly on mammals. These products are generally labeled for outdoor use and may be useful in helping to drive animals out from under decks or other structural additions.
Contact (Touch). Several repellents, containing polybutenes, form an adhesive surface that is uncomfortable for pigeons and other birds. At least one of these products is registered for squirrels.
Shotguns and .22 caliber rifles/pistols can sometimes be used to remove animals from the outside of structures. Inside large buildings, such as warehouses, pellet guns have been successfully used to remove pest birds. Firearms should be used only by individuals who have been trained in firearm safety. Legal restrictions, such as local firearm discharge ordinances, also restrict their use.
These devices, either commercially available or homemade, allow an animal to exit but not reenter a building. Effective bat-proofing often involves the use of such doors, also known as checkvalves. Tomahawk manufactures one-way doors for squirrels.
William Bridgeland, a wildlife consultant, has developed a one-way door technique for snakes. Aluminum insect screening is rolled into a tube and attached over the entry hole, which is usually around the foundation. The tube is angled slightly up and somewhat flattened at its outer end. The snake should be able to crawl out of the tube but not reenter. Insect screening is used because snakes may utilize olfactory clues to find entry holes. Insect screening would diffuse odors and be less likely to direct the animal to the open end of the tube when seeking reentry. When snakes are active (during the summer), the tube should remain in place at least two weeks.
One-way doors are only effective if the animal can find and use the exit and cannot force its way through the door or find another entry point.
Some specialists use certain breeds of dogs (such as the Russell terrier) to help capture an individual animal within structures. This approach can be very effective, but the dogs must be well trained and under careful supervision.
Outside your own home, the application of a pesticide (and legally registered chemical repellents) requires the appropriate pesticide applicator's permit. There are relatively few pesticides available for the control of animals.
Rodenticides. The largest variety of available rodenticides is for commensal rodent control (house mouse, Norway rat). There are two categories of rodenticides: anticoagulants and acute toxicants.
Anticoagulants are slow to take effect and usually require more doses than acute toxicants. With a slower reaction time and vitamin K as an antidote, the risk of accidental poisoning of non-target animals and humans is considered lower than for acute toxicants. However, some of the anticoagulants (such as brodifacoum) have a higher risk of secondary poisoning due to their toxicity at low levels. Secondary poisoning, the poisoning of a predator or scavenger that eats a poisoned rodent, is an important consideration. Also, some populations of commensal rodents have developed resistance to certain anticoagulants.
Acute toxicants are effective with as few as one feeding. Physiological resistance has not been demonstrated, but individual animals may become "bait shy" if they survive the initial exposure. While the risk of secondary poisoning is usually considered to be lower than with anticoagulants, the danger of accidental direct poisoning may be higher.
Fumigants. Use of fumigants is most practical for killing rodents in burrows around the outsides of buildings. Fumigants such as aluminum phosphide and gas cartridges are registered in New York State for use on Norway rats, woodchucks, and chipmunks. When fumigating burrows that are near buildings, you must ensure that the gas does not enter the building. Gas cartridges can also be a potential fire hazard.
Avitrol® baits are poisons with flock-alarming properties. The baits are registered as chemical frightening agents (repellents) for use on pigeons, house sparrows, starlings, and other species. Birds that have fed upon the bait exhibit distress behavior that frightens the rest of the flock away. Although true secondary poisoning does not occur, the product remains toxic to any bird that eats it even once it is in a bird's digestive tract. The possibility of a negative public reaction to dying birds should be considered when planning a bird control program using Avitrol®.
Immobilizing agents (such as Ketamine HCl and xylazine HCl) are heavily regulated by federal and state agencies and, therefore, are not readily available to most pest control operators or the general public. Although they are occasionally helpful for removing an individual animal, they are generally not practical for most animal problems.