Cool, fall weather has arrived and along with leaves and nippy mornings, bugs and rodents are scurrying to find warmer quarters. Often times, those warmer quarters are in the home. Of these invaders, the common or European house mouse is one of the most troublesome and definitely an unwanted house guest.
Droppings, fresh gnawing, and tracks are usually the first signs of mouse activity. Other signs might include nests made from shredded paper or other fibrous material and their characteristic musky odor. They are most active at night but it is not uncommon for them to be seen during the day, too. Common locations for these critters are under the sink, in cabinets or drawers, on the counter, and under furniture with their trails usually running along the baseboards.
These little critters require minimal space to invade a home. Mice can squeeze through openings slightly larger than ¼ inch, just enough space to get their whiskers and head through. They are excellent climbers and can run up any rough vertical surface. They are also “tight rope artists” in that can run horizontally along very thin wires, cables, or ropes. According to Dennis Ferraro, Nebraska Extension Wildlife Specialist, mice can jump straight up two and half feet and across three feet or drop vertically eight feet and keep running at a speed of six miles per hour.
Further, mice have a tremendous reproductive capacity. In a year’s time, a female may have five to ten litters of usually five to six young born 19-21 days after mating. Mice reach reproductive maturity in six to ten weeks. The life span of a mouse is usually nine months to one year.
So with these facts in mind, prevention is key and involves three components—mouse-proof construction, good sanitation or removal of sources of food and water, and population reduction.
Mouse-proof construction. The most successful and permanent form of house mouse control is to prevent them from entering in the first place by eliminating all openings through which they can enter. Conduct a thorough inspection of your home—inside and out. Look for gaps in siding where the siding meets the foundation or where pipes and other utilities enter. Cracks in foundations and loose-fitting doors without proper weather stripping are other obvious places where mice can get in. Since mice are good climbers, don’t forget to check openings around the roof, including attic vents. Use rodent-proof materials to close all openings such as steel wool, hardware cloth, galvanized sheet metal or metal flashing, cement mortar, caulking, and spray foam insulation or combinations of these materials. For how-to-do details, see Rodent-Proof Construction and Exclusion Methods prepared by Cornell, Clemson, UNL, and Utah State Universities.
Sanitation. Eliminating their food and water source is critical to controlling them. Mice are opportunistic feeders that will eat any food discarded by humans. Therefore, clean up spilled food or remove open food in cupboards, drawers, counter tops, and floors under stoves, refrigerators, and dishwashers. Place all accessible food in mouse-proof containers such as glass or store in the refrigerator or freezer. Store pet and bird food in sealed containers. Keep cabbage can lids tightly sealed. Remove pet food and water dishes when not in use and do not leave a glass of water or dirty dishes sitting in the sink.
Outdoors, remove clutter and debris from the perimeter of the house. Keep grass, shrubs, and other vegetation trimmed around the house. Remove any container that could hold water.
Population reduction. Population reduction can be done through a combination of rodenticides, trapping, or by professional extermination. Spring traps are the preferred method; baiting with peanut butter usually works well as long as you put the bait far enough in that the mouse has to work for it. Baits or poisons used indoors should be avoided if possible. Often pets and children are unintended victims of baits and poisons. And mice usually die in the walls or some other hard-to-get-at location where they discompose for a month emitting a foul smell, shedding bacteria, and attracting maggots. Should you need to clean up after a mouse infestation, follow these tips.
A few steps now can prevent those troublesome and unwanted house mice from becoming your guests!