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  • Writer's pictureJoe Taylor

Critter Profile: House Mouse | Part 2

A property management group called reporting that a tenant saw a mouse zip across her bedroom floor. I can usually predict the manager’s first question: “How soon can you get there?!”

In Part I of this two-part article we were introduced to several mouse topics: their natural and urban habitats, seasonal activities, food preferences, and reproduction. This article highlights several other topics, including what evidence to look for when they have infiltrated, common diseases associated with mice, their range of damage, and some techniques to ward off their attempts at entry.

Infiltration Indicators

Two categories of indicators often cue up that a mouse in nearby: sound and physical evidence. This article will touch on both, but we’ll need to devote another article to a fuller consideration. Let’s first think about sounds. With any wildlife, the sounds heard are produced either by their movements or as vocalizations. Making an identification from sounds involved decoding its structure and is highly nuanced. It’s difficult to simply explain what to listen for. It takes practice and improves with experience. This difficulty is accentuated by the fact that the sounds produced by mice heavily overlap with other wildlife. Nonetheless, let’s hit upon an example so we appreciate the technique of making an identification.

If you have concerns about mice, contact Paw Control to share your concerns and discuss removal options.

Mice may register an audible sound while scurrying or building a nest. When building a nest above a ceiling, for example, there is often a scratching noise as they move and manipulate the nesting material. This noise often comes in short bursts, followed by a pause. Because their arms and legs are short, the scratching is usually in rapid succession, like when you scratch your head. Larger animals, with longer arms, will take slightly longer to go through the motions of turning their paws.

Because a mouse’s arms and claws are smaller, their lighter scratching is usually at a higher pitch than larger animals. As stated before, the difficulty here is that making a distinction between species is highly nuanced. If you hear sounds, try to take an audio or video recording so a professional can help with the identification.

It’s usually much easier to identify a mouse by way of physical evidence. Let’s consider one of that is often easily found: mouse droppings. Now is the time to put your sandwich away. Mice produce and excrete their solid and liquid waste separately. They do not designate a latrine area. Instead, they just drop as they go. Their urine doesn’t stand out as easily as their solids, so spend any efforts looking for the solids. Mouse droppings, like many species, are dark brown or black. The exception is when they have consumed solid mouse poison, which gives the droppings a green color.

It is helpful to think of a piece of rice when distinguishing various small animal droppings. A mouse dropping is a bit smaller than an uncooked piece of long grain white rice. The dispersal pattern of mouse droppings often is a mix of scattered and clustered. When a mouse is perching or consuming food, you’ll often find clusters of dozens to several dozen within a 6-inch circle. But because they drop as they travel, you’ll perhaps find random pieces along their travel path. Since a mouse will produce 50 or more pellets per day, this evidence can become readily visible as mice spend more time in a given area.

As stated before we’ll need to devote another blog article to expand on the topic of using sounds and physical evidence to identify a mouse. But let’s next look at some risks associated with mice.


Mice harbor a number of diseases, some of which are transmittable to humans. Mice can be infected by a number of bacteria, including Leptospirosis, Lyme disease, salmonellosis, Rickettsialpox (Rickettsia akari), typhus (Rickettsia typhi). Some of these, such as typhus, are much more commonly associated with rats. Mice also are susceptible to a range of viruses, such as hantavirus pulmonary syndrome (HPS) and lymphocytic choriomeningitis (LCMV).


After plugging in the address provided by the property management group, I drove to the apartment building and met with the tenant. I confirmed with the tenant that she had seen the mouse in her bedroom, but nowhere else. I checked the perimeter of the bedroom and spotted something out of place: a small hole along the bottom of a wall with a cable cord tangling through. The hole was plenty big for a mouse to enter through. I traced the hole and discovered the entry point from outside. In this case, the openings were already there, created by a worker, and the mouse simply took advantage of them. But when I went back into the bedroom, I found some damage that was caused by the mouse: clothing and bedding had been shredded to make a nest. The tenant had no choice but to throw these away. And she gladly did!

Let’s list some common types of damage caused by mice:

  • Destruction of clothing and bedding from chewing

  • Contamination of food, especially as they chew through the packaging.

  • Foul odors from their droppings or when they die and decompose

  • Electrical shortages from chewing on wiring. I’ve seen this with both lights and appliances.

  • Diminishing of insulation’s effectiveness due to burrowing.

  • Psychological damage knowing you have a mouse. Gotta add that one!

Reducing your vulnerability

A harsh reality is that mice spend enormous amounts of time seeking out shelter and food sources. It can feel like they have nothing better to do than to explore your home’s exterior until they find a way in. Nonetheless, let’s look at some ways to reduce the likeliness of mice targeting your home:

  • Remove outdoor food that attracts mice. Bird feeders are a major draw. If you are unwilling to remove a bird feeder, then consider moving it farther away from the house to discourage the mouse from tucking away along the foundation.

  • Be mindful of food sources inside your garage. This could be bird feed, garden seeds, pet food, or even a garbage can with a lid.

  • Keep your garage door closed when not in use.

  • Trim any shrubs and bushes near your foundation, and rake away leaves in these areas before they accumulate. Mice will take cover in these areas, and the idea is to provide little incentive for them to loiter.

  • Consider placing a small number of snap traps in high risk areas, such as the garage. This is a simple way to monitor activity.

This two part series has covered a number of topics related to mice. It was difficult to pare down what to cover to make the article length manageable. Is there a particular mouse topic you would like to know more about? Email me so I can add it to my list!

Do you have additional tips? Leave your ideas in the comments!

Joe Taylor, M.S. Science Education, B.S. Biology, is a full time nuisance wildlife control operator in Eastern Iowa, and owner of Paw Control, LLC. Follow him on Twitter: @pawcontroller at LinkedIn, or the Paw Control blog:



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