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Lethal Control

Toxicants

In some cases, toxicants are used to reduce large populations of a damaging species. Overabundant rodent populations, for example, can be controlled with rodenticides that act as anticoagulants (preventing normal blood clotting) or that cause death by some other action. Anticoagulant rodenticides are used primarily for controlling rodent populations in commensal species (rodents living in close proximity to humans) or for field control of species such as ground squirrels. Strychnine is a rodenticide widely used underground to control pocket gophers to prevent damage to forest seedlings, agricultural crops, and home landscaping. Zinc phosphide is used for many species of field rodents such as prairie dogs and ground squirrels.

A frequently used pesticide for bird management is Starlicide ® Complete or DRC-1339. Starlicide is used to control starlings and blackbirds. DRC-1339 is registered by the U.S. Department of Agriculture/Animal and Plant Health Inspection Service (APHIS) to control pigeons where they cause nuisance or disease problems, starlings in feedlots where they consume cattle feed and spread diseases such as histoplasmosis, blackbirds in crops, and ravens where they are killing endangered species or livestock

Pesticides are also used in predator management. APHIS has a conditional registration for technical Compound 1080 (sodium monofluoroacetate) for use only in the Livestock Protection Collar (LPC), a device placed around the neck of a few sheep where coyotes are killing lambs that will target specifically only those coyotes doing the killing. APHIS also maintains a registration for the M-44, a spring-loaded device containing sodium cyanide that is placed in areas where coyotes or other predators are killing livestock.

Fumigants (toxicants in gaseous form) include sodium nitrate in the gas cartridge, a fumigant for use in coyote, fox and skunk burrows, and aluminum phosphide and sodium nitrate used directly in burrows to control burrowing rodents where they are damaging rangeland, agricultural crops, or carrying plague.

In general, toxicants are used in low volume and only in limited areas (i.e., in the gas cartridge (placed in burrows), the M-44 (placed on paths frequented by predators), and in bait boxes that exclude nontarget animal). Vertebrate pesticides also tend to be fairly selective. Some compounds are more toxic to target than to nontarget species, for example, DRC-1339 is more toxic to birds than to mammals and more toxic to target blackbirds than to most other bird species.

Summary above taken from:

FAGERSTONE, K. A. 2002. Professional use of pesticides in wildlife management - an overview of professional wildlife damage management. Proceedings: Vertebrate Pest Conference 20:253-260.
http://www.aphis.usda.gov/ws/nwrc/is/02pubs/fage022.pdf 589K

Trapping/Snaring

Though some animals live-trapped in cage (box) traps are relocated, most are euthanized. Leghold traps are usually used to capture predators such as coyotes and foxes, and aquatic mammals such as beavers and nutria. Because the animal usually is not killed by the trap, nontarget species caught in traps can be released. Snap traps such as those that can be purchased at grocery stores for mice, are designed to kill instantly. Other killing traps include the harpoon trap used to kill moles in yards and conibear traps commonly used in shallow water to catch beavers, muskrats, and nutria. Snares are wire nooses that tighten around an animal's body (usually neck). Some snares (foot snares) are also designed to act as leghold traps and hold an animal without killing it. (From Conover 2002).

CONOVER, M. 2002. Resolving wildlife conflicts: the science of wildlife damage management. Lewis Publishers, Boca Raton, Florida.

Hunting/Shooting

Shooting is a common way to kill larger animals. In addition, during hunting seasons, the number of hunting permits issued for deer, bear and other animals may be determined by the size of the population. If an animal population is outgrowing its food sources or habitat, increased numbers of hunting permits may be issued to help control the population. Shooters have reduced hazards to aircraft from bulls by instituting a shooting program at John F. Kennedy International Airport. Shooting from airplanes has also been used to reduce coyote populations feeding on livestock. Sometimes shooting is used as an adjunct to the use of frightening devices for harassing animal populations from an area.

Surfactants

Surfactants are chemicals, sprayed on birds, that break down the oil in feathers. In cold weather, feathers soak up water and birds die from hypothermia. Surfactants are sometimes used on huge roosts of flocking birds such as blackbirds, to reduce the population.