Effective rodent control involves sanitation, rodent-proof construction and repair, and population reduction. The first two are useful as preventive measures, but when a rodent infestation already exists, some form of population reduction is almost always necessary.
Trapping is an effective control method. When only a few rodents are present in a building, it is usually the preferred control method. Trapping has several advantages: (1) it does not rely on inherently hazardous poisons, (2) it permits the user to make sure that the rodent has been killed, and (3) it allows for disposal of the carcasses, thereby avoiding dead rodent odors that may occur when poisoning is done within buildings.
Snap traps have been used for centuries. The simple, inexpensive wood-based snap trap is effective and can be purchased in most hardware and grocery stores. Bait traps with peanut butter, chocolate candy, dried fruit or a small piece of bacon tied securely to the trigger. Set them so that the trigger is sensitive and will spring easily. Set traps close to walls, behind objects, in dark corners and in places where evidence of rodent activity is seen. Rodents seldom venture far from their shelter and food supply, so place traps no more than 10 feet apart in areas where they are active. Leaving traps unset until the bait has been taken at least once ("prebaiting") often increases the success of trapping.
An alternative to traps are glue boards, which catch and hold rodents attempting to cross them similarly to the way flypaper catches flies. Place glue boards along walls where rodents travel. Two or three glue boards placed side-by-side (or the larger glue boards used for rats) will be more effective than individual boards. Do not use them where children, pets or desirable wildlife can contact them.
Rodenticide baits are formulated to be lethal to small mammals, and are therefore not selective for the target species. Their lethality is often the result of both their specific anti-coagulant functions and multiple-dose toxicity. As a result, all rodenticide baits pose a high risk of primary poisoning for non-target animals that might eat the bait, including children, pets, birds, and other wildlife. Most of these baits cause rodent death only after they are eaten for a number of days, although some types can cause death following a single feeding. The US EPA indicates that brodifacoum and difethialone are the two highest-risk rodenticides for birds or non-target mammals. Bromadiolone and diphacinone are a close second, and zinc phosphide is also high risk.
Additionally, making your structure rodent-proof is a key component of ongoing rodent elimination. Improving the building's integrity helps deny them entry. Exclusion is the best long term and cost effective method of rodent control, and taking the time to do it right can save you frustration and money in the future. One of the best products is copper mesh, which can be used to fill a hole or opening. Rodents do not have the ability to chew or gnaw through copper mesh fibers.
Rodent baits should be used ideally as a supplement to rodent-roofing the structure. If there is a repeated need to use baits, it is likely that both sanitation and rodent-proofing should be improved. Remember that rodent baits are poisons, and should be handled and used with care.