Pest Identification

          The house mouse (Mus musculus) is one of the most troublesome and economically important rodents in Missouri. House mice live and thrive in a variety of locations. They are found in and around homes and farms, as well as in open fields and agricultural fields. House mice consume and contaminate food for human and livestock consumption. They may cause damage to structures and property, and they may also transmit diseases such as salmonellosis (food poisoning) and swine dysentery.
          House Mouse
The House Mouse originated in Asia and spread throughout Europe many centuries ago. In the early 16th century, it arrived in Florida and Latin America on ships of the Spanish explorers and conquistadores, and about a century later came to the northern shores of North America along with English and French explorers, traders, and colonists.

• Description: Grayish brown above; nearly as dark underneath. It's tail is dusky above and below, nearly hairless, and less than half the body length. It has ungrooved incisors.
• Similar Species: Deer mice (Peromyscus species) have white under parts. Harvest mice have grooved incisors.
• Breeding: Gestation 18–21 days; several litters per year, each of 3–16 young; reproduces spring through fall in North, year-round in South.
• Sign: Musky odor. In buildings: small dark droppings, damaged materials, holes in insulation, and shredded nesting material; in fields: small dark droppings, small holes in the ground.
• Habitat Buildings; areas with good ground cover, especially cultivated fields. Uncommon in undisturbed or natural habitats.
• Range: Pacific Coast south from Alaska through w and s Canada and throughout all of continental U.S.
• General Information:
  • The House Mouse makes its own nest but lives in groups, sharing escape holes and common areas for eating, urinating, and defecating.
  • It takes turns grooming its fellows, especially on the head and back, where it is difficult for the animal to groom itself.
  • If the population grows too dense, many females, particularly adolescents, become infertile. A highly migratory existence and rapid rate of reproduction enable the House Mouse to thrive; it takes advantage of situations not readily available to other species, including cultivated fields, which offer a rich if temporary habitat.
  • As a crop develops, the mice move in and have several litters in quick succession, building large populations quickly; when the field is harvested or plowed, they move out. Many perish, many find other fields, and still others invade buildings. Sometimes these migrations assume plague proportions: In 1926–1927, an estimated 82,000 mice per acre (202,000 per ha) wreaked havoc in the Central Valley of California.
  • In such densities, House Mice, though generally timid, have been known to run over people’s feet and even to bite.
  • In cultivated fields, some of their actions are beneficial, as they feed heavily on weed seeds, with foxtail grass a favorite, along with caterpillars and other insects;
  • In houses, barns, and storage buildings, they are entirely destructive. These mice eat or their droppings contaminate large quantities of grain and other valuable foodstuffs.
  • Their scientific name derives from the Sanskrit musha, meaning "thief." They chew or shred anything chewable or shreddable, including furniture and wires, and sometimes start fires. They can scurry up rough vertical walls and even pipes; they gnaw holes in walls, floors, and baseboards.
  • Like Black and Norway rats, House Mice can spread disease. In the wild, birds and mammals are predators. Centuries ago, cooked mouse meat was a folk remedy for colds, coughs, fits, and fevers, but it is not recommended today. The white mice used in research laboratories are albinos bred from this species.
  
  
  Deer Mouse
  Warning The droppings of the Deer Mouse have been associated with a sometimes fatal illness in humans called hantavirus. Never vacuum or sweep mouse droppings; thoroughly wet the area with a disinfectant, then carefully wipe up the droppings with a wet cloth.
  • Description: Color varies greatly with habitat and geographic area. Often grayish to reddish brown above and white underneath. The tail is distinctly 2 colors and short-haired. The woodland Deer Mouse has a much longer tail and larger feet, ears, and body than prairie Deer Mouse. The Deer Mouse's tracks are similar to White-footed Mouse. Practically all predators of suitable size prey on this species, and since it is so common, it serves as a diet mainstay of many animals.
  • Similar Species: Because it is the most common species in many small mammal communities and is exceedingly variable, the Deer Mouse can be difficult to distinguish from other Peromyscus species. In East, White-footed Mouse’s tail is shorter than that of woodland Deer Mouse (tail of woodland Deer Mouse is more than half total length), and its tail and hind feet are longer than those of prairie form (prairie form’s tail is less than half total length). In West, Piñon and Northern Rock mice have much longer ears. Most other western species have shorter tails.
  • Breeding: Breeding season is variable, usually during the period that provides the best environment and food for raising young. Several litters per year of 2–7 young each; gestation 21–24 days.
  • Habitat: Exceedingly variable: prairies and other grasslands; brushy areas; woodlands.
    • Sign Prairie form: small burrows in ground or nests in raised areas, if available.
    • Woodland form: nests in hollow logs. Western forms: nests in such protected places as underground burrows, clumps of vegetation, hollow limbs on or above the ground, and rock crevices, among others.
  • Range:
    • The Deer Mouse occurs over a large geographic area and range of habitats, and is highly variable in appearance. More than 100 subspecies have been described.
    • in West: S Yukon and Northwest Territories to Mexico; in East, Hudson Bay to Pennsylvania and Appalachians, and across northern tier of states and south into c Arkansas and e Texas.
    • There are two kind of Deer Mice in the eastern part of range: woodland and prairie.
    • The smaller prairie form (P. m. bairdii) occurs throughout much of the Midwest, whereas the many woodland forms occur in the Alleghenies and northward.
  • Food: Deer Mice feed on various foods, including seeds and nuts, small fruits and berries, insects, centipedes, and the subterranean fungus Endogone. The Deer Mouse caches food for winter use, routinely storing seeds and small nuts in hollow logs or other protected areas, but not as extensively as the White-footed Mouse. The most important foods of the prairie form include seeds of foxtail grass and wheat, among other sorts of seeds, as well as caterpillars and corn. The prairie form is common in cultivated areas and remains even during harvesting and plowing periods. It may have additional small refuge burrows as well as home burrows. The woodland form feeds on woodland nuts, seeds, and fruits as well as insects and other invertebrates. In the West, the Deer Mouse occurs in myriad habitats, feeding on the various seeds, fruits, nuts, caterpillars, and other insects available.
  
  
  
  
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