Peromyscus Maniculatus (Transcript)
Biology, Dangers, and Control of the Deer Mouse with pest expert Matthew Hess
Identification and Biology
The deer mouse, Peromyscus maniculatus, also known as the white-footed mouse, is a small and fascinating creature that belongs to a vast group and subspecies within the genus Peromyscus. These small rodents are incredibly abundant and very widely distributed throughout all of North America, making them a common sight in many areas. In fact, they are the most abundant of all the mammals in North America.
Peromyscus maniculatus Habitat
The white-footed mouse can be found in a wide variety of habitats in Kentucky and Tennessee. These habitats include lush forests, open grasslands, dense scrublands, and even agricultural lands. This little mouse is known for its agility and speed, which it uses to evade predators and search for food. In addition to being a skilled runner, the deer mouse is also an excellent climber and jumper. Its small size and quick movements make it a fascinating creature to observe in nature.
These rodents tend to inhabit forests, grasslands, and agricultural crops, and are rarely found in urban or residential areas, unless those areas are surrounded by fields, forests, or other suitable habitats. It is important to take precautions where deer mice are known to be present in order to avoid potential health risks.
The white-footed mouse can be found in a wide variety of habitats in Kentucky and Tennessee, including woodlands, grasslands, and other natural areas.
Deer Mouse or House Mouse?
One way to differentiate the deer mouse from the house mouse, Mus musculus, is by observing its bicolored tail. The deer mouse’s tail has a white underside and a darker color on top, while the house mouse’s tail is almost furless. Apart from this feature, the deer mouse has larger eyes, ears, and overall body size compared to the house mouse. Moreover, the deer mouse typically has a white underbelly, white feet, and legs, and a light to dark brown back. These physical attributes make it easy to distinguish the deer mouse from other mouse species. With this information, it should be easier to identify the deer mouse when encountered in the wild or in urban areas.
Deer mice can be easily identified by their bicolored tail, white underbelly, large eyes, and large ears.
Social, Solitary, or Both?
Deer mice are nocturnal creatures by nature but can also be diurnal. However, they spend most daylight hours in their nests. They are said to be typically solitary except during mating season and in winter. The mating season stretches from March to October; the remaining months are considered winter. It may then be said that deer mice are social. You may get either of those answers depending on what scientific study you read. We chose to narrow it down to the facts: deer mice may be social or solitary, depending on their environment and several other factors.
Depending on environmental factors, deer mice may be social or solitary.
Reproduction and Lifecycle
The deer mouse is often polygynous (males mate with multiple females) but can also be polygynandrous (both sexes having numerous mates). Breeding can occur at any time during the year; however, breeding is at its peak during warmer months. Once the female has given birth, she may be bred again while her offspring (kits or pups) are still suckling. Gestation periods generally last 22-25 days when the female is not lactating but can last 24-30 days when lactating. Litter sizes vary from 3 – 11 and average 4 – 6. The offspring are born altricial but develop quickly. Their eyes open at around 15 days, they will be weaned by 25 – 35 days, and reach sexual maturity at 35 days for females (does) and 49 days for males (bucks).
Deer mice are less likely to breed in the winter outside human dwellings. When plenty of food is available, and populations are stable, their reproduction can continue successfully, even in harsh weather conditions. In the wild, the average life span is less than two years, but life spans may increase in captivity.
A female deer mouse and her suckling pups.
Often, deer mice nest in groups, especially in winter. Nests are often found in elevated or low-lying locations, are messy, and cup-shaped. They may be crafted from a variety of locally-sourced materials from fur, feathers, hair, plant fibers, paper, thin plastics, and other readily available items. Different species of deer mice prefer different nesting locations based on their environment. White-footed mice don’t hibernate, but they can take a daily torpor in extreme weather.
While deer mice nest primarily in the ground, old tree trunks, fallen trees or other abandoned nests in the wild, urban areas also provide a plethora of nesting sites like this engine bay.
Peromyscus maniculatus have an omnivorous diet that includes a diverse range of foods such as seeds, fruits, nuts, fungi, other vegetation, and insects. What’s even more intriguing is their habit of caching food, especially as winter approaches. This behavior helps them survive during harsh weather conditions by stockpiling food in their burrows. They are also known to consume their own feces in order to extract as much nutrition as possible from their food.
Determining if you have house mice or deer mice can be as simple as looking for cached food deposits near nesting sites. If you find any of these, you certainly may have deer mice.
Deer mice will feed on a variety of human foods and pet foods, especially those containing grains.
Threats and Damage
While deer mice may not be common in urban areas, homeowners and business owners alike may be at risk when they are situated close to wooded areas, fields, crops, parks, and other natural habitats. It’s common for deer mice to infiltrate buildings near crop fields during harvest season. Additionally, when the colder months of fall and winter approach, the white-footed mouse may find your home a warm and cozy place to take up residence.
Property and Structure Damage
Since these critters are small, gaining access into a structure is not so difficult. Small gaps, cracks, and crevices that we may overlook, will do just fine. Vacation homes, vacant buildings, log cabins, brick homes, barns, metal buildings, and just about any structure is suitable. Once in, the deer mouse may nest and cache food supplies found inside or just outside the structure.
Damage to property including mattresses, clothing, furniture, thin plastics, paper and other products can be the result of gathering material for nesting. The most telling sign that deer mice are the culprit rather than house mice, is the caching of food. Acorns, nuts, seeds, pet food and other food products found stored in peculiar places, are a sure sign of deer mice.
Simple items like this bar of soap are just the beginning of the damage mice can do.
Damage to this vehicle component is an example of the costly damages Peromyscus maniculatus can create.
Damage in Seed Row Crops
Seed row crops, especially alfalfa seed and melon seeds, are often dug up by the deer mouse soon after planting. This predation can cause significant crop loss, economic decline, and potential shortages. Almonds, avocados, citruses, pomegranates, and sugar beets are also at high risk.
Seed row crop damage by deer mice, like that pictured above, can result in major economic loss and potential food shortages.
Reforestation Seed Damage
Deer mice aren’t only capable of damaging structures and agricultural lands, but forest lands are also at risk. Rodents, especially the white-footed mouse, are predators of seeds and are responsible for the slow regeneration and failure of planted coniferous forests early on.
Many farms hand-plant the Douglas Fir in hopes of reducing seed predation by Peromyscus maniculatus. While several rodent species may be responsible for seed predation, deer mice are ranked as the number one predator of seeds in many parts of the U.S.
Hantavirus Pulmonary Syndrome (HPS)
Deer mice are the main carriers of Hantavirus Pulmonary Syndrome (HPS), which can be transmitted to humans. The virus is present in their urine, saliva, and fecal droppings and can spread when contaminated dust is inhaled. Being in or near areas where deer mice live or nest increases the chances of exposure to the virus.
While HPS is rare, it can cause severe respiratory issues and even death. The mortality rate in humans is less than 36%.
To prevent the spread of HPS by Peromyscus maniculatus, it is important to take measures to keep them out of structures such as homes, barns, outbuildings, vacation homes, industrial buildings, commercial structures, and even farm machinery and vehicles. It is unsafe for people to work, sleep, play, clean, or inhabit areas that are infested with deer mice. If a structure is infested, it should be inspected by a professional pest control company that can provide a secure plan to eliminate the infestation, prevent it from recurring, and sanitize the area so that it is safe for humans to inhabit again.
Note: Working in deer mouse-infested areas to remove feces and urine pillars should be done by trained professionals only.
Peromyscus maniculatus Control
Since Peromyscus maniculatus pose both a threat to human health and damage to property, forests, and agriculture, effective management strategies should be implemented and followed through to ensure loss prevention and safety for humans. Such measures as habitat modification, exclusions, trapping and baiting, and sanitation can not only reduce populations but also prevent them, especially indoors.
Note: Baiting techniques must be done in accordance with rodenticide labels and corresponding laws. Most, if not all rodenticides, exclude deer mice from the label.
Currently active infestations require precision trapping and baiting to achieve control. Once the population has been reduced and the infestation eliminated, professional monitoring must be continued. Familiarizing yourself with the signs of deer mice will also be beneficial. Additionally, exclusion measures will help reduce, if not completely eliminate future infestation possibilities.
Whether an infestation has been recently eliminated or previously eliminated, remnants of deer mice feces and urine may remain. In order to ensure such an environment is free of all contaminants, professional pest control sanitation should be implemented.
Modifying the Habitat
The average range of a deer mouse is between ¼ acre to 3 or more acres, depending on food availability and population numbers. Modifying the habitat to reduce deer mouse populations is a great practice in control efforts. While this won’t typically eliminate entire populations, it will help reduce numbers and make future control measures much more successful.
Habitat modification can be as simple as mowing the lawn, trimming the weeds, trees, and shrubs, and reducing overall ground cover. Stored items like wood piles, construction materials or construction debris, junk vehicles, fallen trees, brush piles, and more should be removed from the property as soon as possible or otherwise moved to a distance of 100 feet or more from any structure.
When possible, modifying the habitat of deer mice by removing ground covering will aid in the prevention and control of infestations.
When possible, it is always more productive, safer, and a more permanent solution to exclude deer mice and other rodents from entering a structure. Since rodents will gnaw on many building materials, even small gaps of ¼ inch are of concern.
Sealing gaps, cracks, and crevices from ¼ inch and larger can be performed with a variety of materials and equipment. Door sweeps, trim pieces, steel wool, metal closures, rat guard, caulking, and other methods and materials may be utilized in exclusions. Materials like plastics, vinyl, foam, and rubber should not be used to except where such products are factory installed, such as door moldings, door gaskets, windows and window gaskets, garage door trim, and other building materials.
It’s important to pay attention to all areas of a structure when preparing for and performing exclusions. Missing one spot could be the difference between success and failure. Inspections should include the roof line, roof penetrations, eaves, soffit, gutter board, downspouts, doors, windows, trim work, and wall penetrations. Additionally, foundations, vents, veneer cracks, foundation cracks, siding imperfections, pet doors, basements, crawl spaces, attics, plumbing penetrations, dryer exhaust vents, and damage or irregularities to any building products, should be noted and subsequently repaired or sealed.
Besides repairs and sealants, often times it may be as simple as closing a garage door, window, or vent exhaust. Peromyscus maniculatus will use these areas to gain entry as well. Be sure you’re not leaving doors or windows open letting rodents gain easy access.
Trapping runs the risk of being exposed to Hantavirus and precautions should be made to avoid contact with rodent urine and feces. This exposure can occur when resetting used traps, emptying traps, and removing used traps. To reduce such exposure, vinyl, latex, or nitrile gloves should be worn when handling rodents or rodent control equipment. Furthermore, disinfecting products labeled to destroy Hantavirus can be used to decontaminate control mechanisms and the area of infestation. Be sure to read and follow all label instructions.
To begin trapping measures, it’s important to understand trap placement protocol. Placing traps further than 10 feet apart in areas of activity reduces the likelihood of success. Since mice typically run along walls, traps should be placed so that the trigger is facing the wall. It’s also important to make sure no obstructions will prevent the trap from tripping or completely closing once tripped. Mice can quickly become trap-shy when trapping measures fail, making future trapping more difficult if not impossible altogether.
Choosing Professional Trapping
There are a variety of snap traps available over the counter. Many of them are difficult to set, potentially dangerous or too weak to perform well. Professionals are often armed with much better trapping solutions that will be very effective when properly used. Furthermore, professionals should have easy access to quality lures that make the traps irresistible to mice. In turn, this aids in preventing failed trapping and reduces the potential for trap shyness.
In heavily infested environments, multiple traps should be used simultaneously. Infestations should be inspected and population numbers estimated to ensure the proper number of traps are placed. Once traps are set, return visits should be made daily until traps begin to be empty upon inspection. Then visits can be reduced to accommodate the remaining population.
Note: Glue boards should be avoided when controlling deer mice due to the risk of Hantavirus (HPS) exposure.
Seeking Professional Help
There’s no shame in seeking the help of a professional pest control company. When the threat of economic loss and health concerns are present, there’s no time for hoping you have success. Eliminating the problem right away is warranted. To do so, hiring the right company is crucial.
Of course, Four Seasons Pes Solutions is always ready to help. We have a team of service technicians ready to get your rodent problem solved and even prevent it from recurring if you so choose.
Give us a call and find out why everybody says that it’s good to have Four Seasons on your side!
It’s good to have Four Seasons on your side!