By: Kelly Feehan, Extension Educator

When it’s cold outside, mice try to find warmth inside.  In one year, all offspring and subsequent generations from a single pair of mice could add up to 10,000 mice.  Hence they are a common problem.

Dennis Ferraro, Nebraska Extension wildlife specialist, recently shared some tips for keeping mice out of residences and for trapping them. The best control is to prevent their entry indoors and sanitation. 

 According to Ferraro, understanding the abilities of mice will help in keeping them out.  For example, an adult mouse can squeeze through an opening as small as three-eighths inch.  Like cats, their whiskers tell them if the opening is large enough.

Mice are able to jump straight up two and a half feet and across three feet.  They can climb brick and stucco, and walk on about one-tenth inch diameter wire.  Mice can run up to six miles per hour; and drop vertically eight feet and keep running. 

The home range of a house mouse is usually a 20 foot radius, but their curiosity will have them exploring up to 200 feet from home base.  Their preferred path is along walls, whiskers guiding the way.

Mice urinate and defecate on the go, as many as 80 droppings a day.  For identification, their black, quarter-inch droppings are pointed on both ends.  Feces carry disease-causing organisms so wear gloves if handling

To prevent entry, pack three-eighth inch and larger openings with copper wool or stainless steel wool (make sure it is without iron which will rust), then caulk over. Caulking prevents mice from chewing through or pulling out the material.

For sanitation, eliminate access to food, water or nesting material. Clean up food and crumbs and fix water leaks.  Even simple things like storing a damp mop on the tip of its handle with its head in the air, can prevent mice from obtaining moisture or nesting material, according to Ferraro.

Avoid using mouse poisons and trap instead. “Using baits indoors should be avoided at all costs,” Ferraro said. One reason is children and pets are often unintentional victims.  And mice are likely to crawl into a wall to die where they can decompose for a month, shedding bacteria and attracting maggots.

When cleaning where mice have been or droppings are found, avoid sweeping and vacuuming.  Disease causing organisms in the droppings will spread once airborne. 

When cleaning, ventilate the area.  Wear a respirator or quality dust mask, and spray the area with a disinfectant before cleanup. The moisture in diluted bleach or disinfectants prevents disease-causing organisms from becoming airborne and inhaled.

When trapping, pre-bait by putting out food such as peanut butter. After mice eat the pre-bait, place the same food firmly on a trap.  Wear gloves, then set traps along walls where mice travel.  For a snap trap, set the snapping mechanism toward the wall so a mouse is less likely to drag it away.  

If using glue traps, place any bait in a small container like a bottle cap. This prevents bait oils creating a ‘slick’ on top of the glue so mice get away.  Wearing gloves, check traps twice a day.  Bacteria in and around a dead mouse will multiply. Gloves help prevent contact with bacteria, lice and fleas. 

When disposing of a dead mouse, wear latex gloves, spray the corpse with disinfectant, double bag it and dispose in the trash.  Wash and disinfect traps to prevent bacteria from spreading; then wash gloved hands before removing the gloves. Fleas and bacteria can spread from mice, even when trapped or dead.