Non-Chemical Mouse Control

The first step to effective mouse control is sanitation. When talking about mouse control, this means more than tidying the place up. It means systematically depriving mice of food, harborage, and nesting materials.

Mouse droppings, spilled food, and nesting materials should be removed from areas where they are found. To avoid illness, this must be done very carefully. Mouse droppings and other by-products associated with mice may contain pathogens and parasites, so don't touch them with your bare hands.

In addition, because pathogens are microscopic, you shouldn't vacuum droppings and other contaminated items with an ordinary vacuum cleaner, as this may just cause the pathogens to become airborne.

A better solution is to spray the droppings and nesting material with a non aerosol, pump-type disinfectant spray, let them dry, and then remove them. Most any high-quality disinfectant can be used; or you can make a mixture of 12 parts water to 1 part household bleach and spray the mixture on the contaminated areas using a pump-type sprayer.

Always wear rubber gloves and wash your hands carefully after working with either mouse by-products or chemicals.

Exclusion

The next step in mouse control is exclusion. This means making structural changes -- such as caulking, sealing, or installing door sweeps -- to keep mice out of the building.

Since mice can squeeze through any hole as big around as your little finger, or through a crack the width of a pencil, mouse exclusion can be a daunting job. But it is essential to long-term mouse control.

We could go into great detail here about rodent exclusion; but since the U.S. National Parks Service has been kind enough to write an entire manual about it, we suggest you just click here to download it. (It's a .pdf file; you'll need Adobe Acrobat Reader to view it. If you don't already have it, you can download the free Adobe Acrobat Reader here.)

Trapping Mice

Whenever possible, we recommend trapping mice, rather than poisoning them. Trapping produces faster results and avoids the risks associated with chemical rodenticides. It also eliminates the risk of a poisoned mouse dying in a wall void or other inaccessible area and decaying there. Mice that die in areas from which they cannot be retrieved can cause odor problems and serve as a breeding area for flies. Their displaced ectoparasites will also look for new hosts, and may infest people or domestic animals.

Individuals handling any rodent trap should wear rubber gloves and wash carefully with an anti-microbial soap after handling the traps.

Here are some of the more common types of mousetraps in use today.

Snap Traps

The oldest and most commonly-used trap is called a "snap trap." Commonly used baits include peanut butter, dried fruit, jelly beans, and gumdrops. (Contrary to popular belief, cheese is not a very good mouse bait.)

The trap on the right has an "expanded trigger" that includes a sensitivity adjustment, which should be set heavy enough so as not to trigger because of vibration, but light enough that a mouse can trigger it.

Snap traps are placed perpendicular to a wall or vertical surface along mouse runways or areas where droppings have been found, with the trigger end against the wall.

Multiple-Catch Mousetraps

Windup, multiple-catch mousetraps are best placed along mouse runways with their entrance holes a couple inches away from and facing the runway.

Mice are naturally inquisitive, and will enter the hole as they pass by. They then step on a pedal and are flipped by a paddle-wheel type of device into a holding chamber. Usually they are not injured in the process, although once in a while they are.

Multiple-catch mouse traps are most often used by professional exterminators. They’re even approved for use in federally-inspected food manufacturing plants.

Electronic Mouse Traps

A more high-tech twist on the multiple-catch mousetrap is an electronic mouse trap. This trap kills 40 to 50 mice with one set of batteries, with no chemicals. These traps are especially useful for mouse control in unattended places like camps, bungalows, cabins, sheds, and so forth.

Sticky Traps ("Glueboards")

Glueboard traps are cardboard or plastic trays covered with a sticky glue. They are placed along mouse runways, and mice simply get stuck to them. Glueboards are most effective in dry, clean, room-temperature areas. They must be changed frequently, as accumulated dust and debris on the traps will render them ineffective.

Although quite effective, many people object to glue traps as being inhumane. In fact, they are illegal in some countries. Trapped mice sometimes squeal helplessly for hours (or even days) before they die. If this bothers you, then don't use them.

Humane Mousetraps

A number of companies manufacture humane mouse traps that are designed to trap mice alive and unharmed, so they may be relocated elsewhere rather than being killed.

Humane traps are an option for those who feel bad about killing mice, but who nonetheless prefer not sharing their homes with them. In some localities, however, releasing trapped mice may be illegal; so check your state and local laws. It would be very embarrassing to go to jail for humanely releasing mice… "Hey, whatcha' in for?"

Humane mouse traps need to be checked frequently, lest trapped mice starve to death in the traps, which would defeat the purpose of using a humane trap. Care must be taken when handling the traps; mice have ectoparasites that can cause disease.

Humane mouse traps can be found in most hardware stores.

Chemical Mouse Control (Poisoning)

Disadvantages of Using Rodenticides

Controlling mice with rodenticides is usually unnecessary and has a number of disadvantages.

Poison baits designed to kill mice are often toxic in varying degrees to humans and other animals, if those baits are ingested (although the amount of rodenticide needed to kill a larger animal is usually many times more than needed to kill a mouse because the toxic effects of most rodenticides are dose-dependent depending upon the animal's weight). Nonetheless, many domestic pets and other non-target animals, and some humans, are accidentally poisoned by rodenticides every year.

Some (not all) rodenticides also exhibit secondary toxicity. The way this works is that if a mouse eats a poison that is secondarily toxic, then the mouse itself becomes toxic. If another animal (like a dog or cat) eats the mouse or its carcass, that animal can be poisoned by the rodenticide in the mouse's body.

Aside from the toxic risks associated with rodenticides, there is also the risk of poisoned mice dying inside wall voids or other inaccessible structural elements of a building. This can happen even when the poison is set outside the building, as it may take as long as a week for mice to die after eating some poison baits.

So whenever possible, try non-chemical mouse control methods first, and use poisons only when necessary.

Proper Selection and Use of Rodenticides

When the use of rodenticide baits for mice is necessary, parrafinized anticoagulant baits which contain the active ingredient bromadialone, are recommended. Bromadialone should only be applied by a professional pest control technician.

Paraffinized baits (and rodenticides in general) should be used inside tamper-resistant bait stations. The use of bait stations not only helps protect children and non-target animals from accidental ingestion, but also helps keep the bait fresh and clean. In addition, mice are naturally inquisitive and will be attracted to the opening. Once inside the station, mice feel more secure and are more likely to feed freely, making the bait station more effective than simply using exposed bait in trays.

The placement of bait stations is not that different from the placement of traps. The stations should be placed along mouse runways with the open ends in the mice's paths. They should be secured to a surface with screws, nails, glue, or heavy-duty double-sided tape. Care should be taken not to place rodenticide stations in areas in which mice may track rodenticide particles onto food, food handling surfaces, or other sensitive areas. As with any pesticide, always read, understand, and follow the label instructions.

But remember: poisoning should be looked upon as only a small part of an overall mouse control program. Sanitation, harborage reduction, and exclusion are the real keys to long-lasting protection against rodents.