The House Mouse
House mice do not cause such serious health and economic problems as Rattus norvegicus and R. rattus. Mice are agricultural pests in some areas, however, and they do consume and contaminate stored human food with their droppings. They also destroy woodwork, furniture, uphostery, and clothing. In addition, they contribute to the spread of diseases such as murine typhus, rickettsial pox, tularemia, food poisoning (Salmonella), and bubonic plague.
The house mouse (Mus musculus) is a small, slender rodent that has a slightly pointed nose; small, black, somewhat protruding eyes; large, scantily haired ears, and a nearly hairless tail with obvious scale rings. The adult mouse weighs about 2/5 to 4/5 ounces. Mice are generally grayish-brown with a gray or buff belly. Similar mice include the white-footed mice and jumping mice (which have a white belly), and harvest mice (which have grooved upper incisor teeth). Native to central Asia, this species arrived in North America along with settlers from Europe and other points of origin. A very adaptable species, the house mouse often lives in close association with humans and therefore is termed one of the "commensal" rodents along with Norway and roof rats. Following their arrival on colonists' ships, house mice spread across North America and now are found in every state including coastal areas of Alaska, and in the southern parts of Canada.
Food Habits
House mice eat many types of food but prefer seeds and grain. They are not hesitant to sample new foods and are considered "nibblers," sampling many kinds of items that may exist in their environment. Foods high in fat, protein, or sugar may be preferred even when grain and seed also are present. Such items include bacon, chocolate candies, butter and nutmeats. A single mouse eats only about 3 grams of food per day (8 pounds per year) but because of their habit of nibbling on many foods and discarding partially eaten items, mice destroy considerably more food than they consume. Unlike Norway and roof rats, they can get by with little or no free water, although they readily drink water when it is available. They obtain their water needs from the food they eat. An absence of liquid water or food of adequate moisture content in their environment may reduce their breeding potential.
General Biology and Reproduction
House mice live in and around homes, farms, commercial establishments, as well as in open fields and agricultural lands. The onset of cold weather each fall in temperate regions is said to cause mice to move into structures in search of shelter and food.
House mice are mainly nocturnal, although at some locations considerable daytime activity may be seen. Seeing mice during daylight hours does not necessarily mean there is a high population present, although this usually is true for rats. Mice have poor eyesight, relying more on their hearing and their excellent senses of smell, taste and touch. They are considered essentially colorblind.
House mice can dig and may burrow into the ground in fields or around structures when other shelter is not readily available. Nesting may occur here or in any sheltered location. Nests are constructed of fibrous materials and generally have the appearance of a "ball" of material loosely woven together. These nests are usually 4 to 6 inches in diameter.† Litters of 5 or 6 young are born 19 to 21 days after mating, although females that conceive while still nursing may have a slightly longer gestation period. Newborn mice are naked and their eyes are closed. They grow rapidly and after 2 w3eeks they are covered with hair and their eyes and ears are open. They begin to make short excursions from the nest and eat solid food at 3 weeks. Weaning soon follows, and mice are sexually mature as early as 6 to 10 weeks old. Mice may breed year-round and a female may have 5 to 10 litters per year. Mouse populations can therefore grow rapidly under good conditions, although breeding and survival of young slow markedly when population densities become high.
House Mouse Behavior
During its daily activities, a mouse normally travels an area averaging 10 to 30 feet in diameter, seldom traveling further than this to obtain food or water. Mice constantly explore and learn about their environment, memorizing the locations of pathways, obstacles, food and water, shelter and other elements in their domain. They quickly detect new objects in their environment, but they do not fear novel objects, as do rats.
Regional Pest Management's Mouse Control Process
There are four basic steps to implement when confronting a mouse infestation:
- Inspection
- Sanitation
- Exclusion
- Population Reduction (Traps, Baits, Repellents)
In order for your rodent control program to be effective (as well as efficient) on a long term basis, all four basic steps should be implemented.
INSPECTION: When Regional Pest Management treats your mouse infestation problem, there ten signs we look for during initial (and follow-up) inspections: Droppings, tracks, gnaw marks, burrowing, runways, grease marks, urine stains, live or dead rodents, rodents sounds and rodent odors. Our inspection gives you a better idea of the size of the population and the routes taken by the rodents.
SANITATION: In order for a large population of rodents to flourish, there has to be an abundance of food and water, as well as easy access to a cozy nesting site. By removing or reducing the factors that make any pest population abundant, you remove and reduce the pest. This is the backbone of integrated pest management!
Sanitation does NOT imply that you live or work in a pig pen! Proper storage of possible rodent food, removal of undesirable vegetation (grass, weeds) and taking care of rubbish, lumber piles or old equipment are just a few examples of good sanitation practices. Homeowners must also realize that pet foods and wild bird feed are all tasty meals for rodents.
EXCLUSION: Controlling rats and mice by making it impossible for them to enter structures is the best way to eliminate and control indoor populations. Although this is not always feasible, exclusion should not be ignored. It is not always possible to do extensive rodent proofing, but in many cases it can be accomplished with minimum effort, and you can count on Regional Pest Management to point out to you how this may be done. A building can be rodent-proofed by eliminating all openings larger than 1/2 inch for rats and 1/4 for mice. Even after this is done, rodents can slip through open doors and windows, gain access along plumbing and other utility lines or (especially in the case of mice) be transported indoors with any merchandise. Exclusion also includes repairing doors and windows that do not operate properly or shut securely. Do not forget to inspect and repair air vents that may not be in sound working order.
POPULATION REDUCTION: To quickly reduce the population of mice, traps and/or baits are used. In some situations, the use of toxic baits are not safe, legal or desired because of possible odors. When dealing with mice, we prefer a combination of traps and baits if possible. We consider your building, the presence of children and pets, and the ability to deal with possible odors and dangers when choosing products to eliminate your mouse problem.