Mice…Maybe Cute But?
As we approach winter, wandering furry mammals tend to look toward warmth and shelter. Enter the world of mice! The three most common species of mice likely to create pest pressures for property owners are the house mouse, the deer mouse, and the white-footed mouse.
Tale of the Tape
Size
These three species of mice are quite similar in both size and weight. They are typically about 5½ to 7½-inches long, including the length of their tail. The house mouse is usually the smallest of these species.
Color
- One of the most obvious distinctions within these species is coloration. The house mouse is gray-brown with an almost completely hairless tail that is as long or longer than the body.
- The deer mouse is grayish-brown to reddish-brown with white-colored undersides and feet and a tail that is less than half the body length.
- The white-footed mouse looks almost identical to the deer mouse, except for its larger size.
Behavior
Each of these three mouse species is primarily nocturnal and quick to escape from dangerous situations. If mice are seen during the day, it is likely a house mouse. The house mouse and the white-footed mouse are both good climbers and swimmers. House mice stay close to their nests rarely traveling more than 100 feet from the nest whereas the white-footed mouse and the deer mouse are more likely to venture farther.
Mice are likely to store food in their nest or burrow and are considered omnivores. In their wild, non-domestic settings, mice eat many kinds of plant leaves, stems, seeds, plant roots, fruits, berries, and insects. Deer mice will also consume their own feces. When occupying areas close to humans, they will eat whatever is left lying around and easily available to them.
The house mouse prefers to live near people’s homes, but they also will live in fields and woods. However, they seldom stray too far from buildings and are the most likely of the three to infest urban areas. As the weather begins to cool, they seek shelter that is frequently a home, storage shed or barn. The deer mouse is found in many different habitats including forests, deserts, grasslands, and agricultural fields. However, its most common living environs are prairies, bushy areas, and woodlands. White-footed mice are most likely to inhabit woodland, suburban and agricultural environments. Rodent surveys have shown that white-footed mice are the most abundant small rodents in the mixed hardwood forests of the eastern part of our country and in brushy areas that are adjacent to agricultural fields.
Reproduction
The house mouse breeds year-round inside structures such as homes. However, in its wild environment, the breeding period is generally from about April through September.
Females generally have 5-10 litters per year and litter-size ranges from 3-12 pups, but most commonly about five or six. Females reach sexual maturity at five to six weeks of age and will live for about one year in the wild and up to two years in protected spaces.
In the typical deer mouse environment, reproduction is either nil or severely limited during the winter months. Litter-size varies from 1-11 offspring with a typical litter of 4-6. Expectedly, reproduction is greater in the warmer parts of the country than in colder climes.
In the north, breeding and birthing of white-footed mice occurs mostly in the spring and late-summer or fall. Adults are ready to mate at about 40 days of age, have from 2-4 litters per year, with each litter varying from 2-9. White-footed mice live for only about a year in the wild.
Do Rodents Pose a Concern?
In addition to being tough to control, rodents may carry diseases and taint food with waste, fur, and saliva. In fact, mice can contaminate about 10 times the amount of food they eat. The Centers for Disease Control link some rodents to transmitting hantavirus pulmonary syndrome, a disease fatal in about 36 percent of all reported U.S. cases.
Rodents are also hosts to fleas, which can spread plague and diseases like lymphocytic choriomeningitis virus. This illness mostly affects those with weakened immune systems and may result in headaches, fever, and meningitis. It can also cause complications during pregnancy.
It is not advisable to handle any wild rodent. They are equipped with large teeth and can transmit a variety of bacteria, viruses and diseases through their saliva, feces, and urine. If you locate a rodent within your home, it is best to contact a pest management professional for removal and identification. The presence of one rodent within a home could signal an infestation. REMEMBER…keep all children and pets away from the rodent. If cornered, a rodent will bite to defend itself.
Signs of An Infestation
Seeing a mouse is an obvious sign of an infestation, especially given the fact that mice are very secretive and nocturnal. The appearance of a mouse can indicate a larger population, since other adult mice typically occupy more protective, hidden places for mice to nest. Most often these animals are spotted scurrying along walls or running to and from areas normally not disturbed.
Mice droppings are found in locations where mice live, travel or stop to eat or collect food. Removing droppings and reinspecting thereafter is a good way to determine whether a mouse population is still active inside a structure. Always use respiratory protections when removing mice droppings. Footprints and tracks left in dusty locations can also be a certain sign of a mouse infestation.
Mice like to gnaw and chew on items in their surroundings. Therefore, the appearance of chewed debris such as paper, bits of food, pieces of plastic or bits of wood and gnaw marks along the edges of wood or other hard materials in frequently traveled areas indicate the presence of mice. If one sees food packages that appear to be chewed, a mouse infestation may be likely.
Often, one hears noises such as mice scurrying from one location to another or from gnawing and scratching within walls or attics are also signs of an infection. And unfortunately, odors from a dead mouse or urine and fecal deposit are a very unpleasant indicator of a mouse infestation.
How Best to Treat for Mice
Almost all mice problems require the use of an Integrated Pest Management (IPM) approach. As discussed, the house mouse, deer mouse and white-footed mouse have somewhat different habitats and behaviors. Therefore, the first thing your pest management professional (PMP) will do is correctly identify the mouse pest and develop a treatment plan that is effective and efficient for the species causing the problems. Probably the most important factor to consider is whether mice are living inside or outside the structure and where they are going to feed. With this in mind, your PMP can design an effective treatment plan. Once prepared, you’ll be educated about what the PMP will do and how their actions will affect the mouse population.
Depending on your specific situation, your PMP will employ both non-chemical and chemical methods. Non-chemical methods are not only effective, but also result in the need to use fewer chemical methods to achieve control. Some effective non-chemical control procedures they will recommend include:
1. Exclusion and sealing off sites that allow mice to enter a structure. Your PMP can suggest sealing openings greater than ¼-inch using screen, flashing, door sweeps, heavy-duty sealants, and other exclusion materials. Keeping mice out of the structure is not always a simple project. However, exclusion is the single, best long-term way to deal with mice problems. We do provide some minimal exclusion and recommend to you what needs a contractor.
2. Your PMP will recommend using both inside and outside sanitation measures to help minimize available food and water that attracts and supports a mouse population. Also, they will recommend removing vegetation, debris or clutter that creates hiding places mice can use as harborage sites.
3. Often your treatment plan will include using traps and other mechanical devices to kill or remove mice.
In addition, your PMP may also recommend the use chemical products, such as rodent baits, that are formulated to kill mice. While baits are highly effective, caution must be exercised to ensure that baits are properly placed, contained with tamper proof bait stations and the instructions on the product’s label are strictly followed.
Keep one final thing in the forefront of your mind! DO NOT procrastinate when you see signs of a mouse problem. The female house mouse is a very prolific animal; wait too long to start control measures and a few of them can quickly become a large infestation.
Prevention Tips
To prevent mice from entering the home, seal all cracks, crevices, holes and gaps larger than a pen cap with cement or a mixing compound. It is not advised that wood be used as mice are capable of chewing through those surfaces.
Cleanliness may also have a significant impact on mouse infestations. Be sure to wash dishes immediately following use. Food should be stored in glass or metal containers with tight lids. Mice acquire most of their water from scavenged food particles, so no crumbs or morsels should be left on tabletops or floors.
When a home is already infested, prevention methods alone prove inefficient.