Deer Mouse
Appearance:
Adult deer mice have a head and body length of 2 3/4 to 4 inches, a tail length of 2 to 5 inches and a weight of 3/8 to 1 1/4 ounce. Deer mice are bi-colored, pale grayish-buff to deep reddish-brown above and white below. The tail is always sharply bi-colored, longer than half the length of the head and body combined, and covered with short hairs. Young deer mice are similar to adults but are gray on the upper surface of the body.
Habitat:
Female deer mice usually have 3 to 5 young per litter (range 1 to 8). The gestation period lasts for 21 to 24 days. There are 2 to 4 litters per year with the surge of reproduction occurring in the spring. They begin to breed at 5 to 6 weeks of age. The life span is 2 to 24 months because of high predation, but 5 to 8 years in captivity.
Deer mice are of medical concern because they are the primary source of hantavirus which causes Hantavirus Pulmonary Syndrome (HPS) this virus is transmitted primarily by the inhalation of dust particles contaminated with the urine and/or feces from infected deer mice. The incubation of this disease is up to 30 days. If death is to occur, it will happen within 12 to 35 days after contracting the disease and it will be the result of the lungs filling up with fluid and/or a heart attack. HPS has a fatality rate of 40% to 50%.
Deer mice are nocturnal. Their runways are poorly defined and they often use the runways of other small mammals. They are excellent climbers and can utilize the upper areas of buildings.
Outside they nest in old fence posts, tree cavities, log piles, bird and squirrel nests, abandoned animal burrows, beneath desks, or dig small burrows. Inside, they nest in storage boxes, stuffed furniture, wall voids, on sill plates, in structural corners, and tight places in basements and attics.
Food is stored for the winter in hollow logs and other protected places. Deer mice have a home range of 1/2 to 3 acres. A summer population of 10 to 15 per acre is high and some congregate in winter.
During the colder months, they frequently enter homes, garages, sheds, and occasionally stored RVs and other infrequently used vehicles. They may damage foodstuffs and furnishings. In unoccupied summer and vacation homes, the damage to upholstered furniture which they used for nests or nesting materials can be extensive.
Deer mice are rarely a problem in urban or residential areas unless the homes border on wooded areas, such as parks. They are common in farming/rural areas and rustic suburban areas.
Diet:
They feed on insects, seeds, nuts, berries, small fruits, a subterranean fungus (Endogone), and other small animals such as centipedes.
Solutions:
What you can do: The key to any mouse control program is pest identification, sanitation, harborage elimination, and mouse proofing the building. If deer mice are already in an occupied structure, professional pest management by Quik-Kill is recommended. Exclusion is the best preventative control method. All potential entry holes (any hole or gap that is the diameter of a pencil or larger) should be sealed with 1/8-inch mesh hardware cloth, copper gauze or silicone caulk. To reduce structural attractiveness, store birdseed and dry pet foods in areas other than the garage or storage sheds.
Because deer mice are the primary carriers of hantavirus, it is prudent to practice minimal safety precautions if a nest is discovered or dead deer mice must be handled and removed. These include:
- Wear a respirator equipped with HEPA (high efficiency particulate air) filters when working with rodent traps, in confined areas with urine and/or droppings, or with dead mice.
- Wear rubber or plastic gloves when handling mice or traps; these should be disinfected before removal.
- Treat dead mice with a disinfectant mist before handling and/or use the inverted bag technique (turn the bag inside out and use as a glove, pick up the mouse and while holding on to mouse, turn the bag right-side out again, and seal the bag).
- Disinfect any droppings before removal; if a vacuum is used, it must be equipped with a HEPA filter.
- If febrile (feverishness) or respiratory illness develops within 45 days of potential exposure, seek immediate medical attention and inform the attending physician of the occupational risk.
Professional Solutions:
A Quik-Kill pest management professional will determine where mice may be entering the structure (e.g., gaps larger than 1/4 inch) and either make recommendations for exclusion or perform the exclusion if contracted to do so. A toxic baiting program will be employed indoors (e.g., beneath kitchen sinks, behind large appliances, in attached garages, attics, crawlspaces, basements), and possibly outdoors where mice are active along foundation walls and under decks.
Tamper-resistant bait stations will be used to contain rodenticide baits, except in attics. Rodenticide tracking powder may be sparingly used in infested structural voids. Small snap traps may be utilized to capture mice if baiting alone is inadequate to eliminate an infestation expediently.
