September 2020
Matthew Hess

How to Know if I Have Mice

A standard online search topic is, “How to know if I have mice?” Truthfully, it isn’t always as simple as seeing droppings or hearing activity at night. Infestations of mice don’t always manifest themselves right away. Here at Four Seasons Pest Solutions, we have heard the same repeated statements over and over for years, “We didn’t even know we had a problem until you found it!” Sometimes small infestations can go undetected for years, but their threat is genuine even then.

Searching for food, shelter, and water, mice often enter homes and businesses, subsequently taking up residence. Once reproduction begins, the offspring know only one home. An infestation is now well underway. Infestations may grow to enormous proportions before becoming a noticeable or visible problem. Mice are great at staying hidden and are extremely intelligent, often even outsmarting the average person who may try to catch them. However, a trained eye should be able to spot signs of infestation long before the problem gets out of hand and therefore begin elimination rather quickly. That’s what we do here at Four Seasons Pest Solutions! Education on rodents and other pests is a matter of utmost importance to us and our staff.

How to Know if I Have Mice by the Tell-Tale Signs

It doesn’t matter where you live, mice are certainly no respecter of persons, and they’re a crafty pest too. Intelligent and able to sneak in through tiny areas, infiltrating the average home is no problem for a mouse. If they can get their nose through it, they’ll get the rest of their body through it too. This is especially true when adequate food sources are available. Their ability to squeeze through tight spaces means the average, untrained individual may be perplexed about how they are getting in and may not suspect their presence immediately.

Small cracks and gaps under and around entryways, like this small crack under a commercial building door, allow easy access for rodents to make their way inside. It should be sealed to prevent mice if it’s larger than 1/4 inch.

It is essential to know if you have a mouse infestation before it becomes a significant problem. Early detection is key. The reproduction rate of mice is high enough to cause alarm if you see only one mouse. There are also several health concerns to consider, such as allergies, asthma, diseases, structural damage, economic loss, and even structure fires. These are all possibilities if you have mice. Knowing the signs and evidence they leave behind can help you spot such infestations early on, just like the pros. This might save a life too, but at the least, it will stop infestations from happening.

Signs to Look for, to Know if You Have Mice

Knowing the tell-tale signs of a rodent-infested structure is critical to preventing and eliminating them. While not every person is well-trained for this sort of work, a little help can point you in the right direction.

If you suspect you might have mice, there are several key factors to look for. Even if there is no initial suspicion of a rodent infestation, knowing the signs may cultivate new hunches should any of the following be recognized:

Scratching noises in ceilings or walls

You may have a mouse infestation if you’ve been hearing scratching noises in your ceilings or walls. Since they are nocturnal, mice are usually heard best in the late evening to early morning. Scratching noises often come from the attic, within the walls, or under the floor. This noise is not usually from movement, but rather, it’s likely from gnawing and burrowing through items such as drywall board, wood, pipes, ductwork, and even electric wires. Mice are generally very quiet animals, but when it’s silent inside and out late at night, their little noises become much more pronounced and easily heard. This can cause the homeowner, who is trying to sleep, a great deal of disconcertment and possibly some sleepless nights.

Mice will burrow in attic insulation to make passageways, nests and harborages

The most common complaint of noise from rodent activity comes from those who have rodents burrowing through insulation in their attic. This keeps homeowners awake and depletes the R-value of insulation, allows feces and urine build-up, and is a potential fire hazard.

Chew or Gnaw Marks

The teeth of mice never cease growing. They will undoubtedly chew on something wherever they are. If in your house, so be it; their marks will be left behind. Maybe it’s on food items in your pantry. It could be on your baseboard trim, wallboard, or a corner near the floor. Perhaps it’s more severe, and they have chewed on HVAC ductwork, plumbing pipes, or electric wiring! Either way, where there are mice, there will be gnaw marks.

Mice and rodents can chew holes through walls and ceilings to access the living quarters of a home

Mice will also chew holes through walls and ceilings to access food sources or new harborage areas. This can cause significant damage in larger infestations and become a severe health threat.

Mice may inhabit our attics, crawlspaces, and walls long before we realize they are present.

Rodents can cause electrical fires by chewing through the insulated portion of wiring

Mice can cause serious concerns by chewing through wiring insulation, exposing live wires which may arc and cause structure fires.

Fecal deposits (Mouse droppings)

Mice can drop 30-80 fecal pellets a day. These are rice shaped and roughly 1/8 to 1/4 inch long and maybe your first clue in verifying an infestation. Put on your Sherlock Holmes hat and grab your magnifying glass… you’ll need them! You want to determine if the droppings are fresh or aged. Aged ones make the best black rice… NO! I’m kidding!! But seriously, if you find moist droppings, you have recent activity and need control measures immediately to prevent further infestation and potential damages.

Dry droppings, however, don’t necessarily mean the activity is old. It could be that it’s just not recent enough to contain moisture. Maybe they’re only a few days old, or perhaps a few weeks. Who knows, maybe they have been there for years! Looking for dust and debris where dry droppings are found can help determine the age. If the droppings are covered lightly with the same dust next to them, they might have been there a while! It takes some good detective work, but nothing a good, strong-minded, and intelligent person like yourself couldn’t do, especially with a bit of information!

Fresh Dropping and Old Droppings Aren’t the Same

We receive many calls regarding rodent infestations. In several of these cases, we find years-old droppings that have not been cleaned up. In response to this, we often hear, “Oh, I just cleaned that last week.” The truth is that trained professionals know the difference between fresh rodent droppings and old ones. Time has a way of getting away from us; what seems like last week can often be last year. If you discover rodent droppings and aren’t sure how fresh they are, call a pro to assess your situation. Don’t place traps or rodent bait until you know a problem requires them.

Mice can drop 30-80 fecal pellets per day. These are about the size of a grain of rice/

Around 6mm in length, these droppings will show up inside cabinets, under furniture, in corners, against walls, and any place a mouse might be found.

Rodent Nests or Nesting Sights

If you discover a mouse nest, you can be assured you have an infestation or have had one recently. You may find shredded paper products, fabric, cardboard, materials used for packaging or stuffing, plastics, and any other materials they may find readily and easily available. This may be in a drawer, a closet, under furniture, or even in a vehicle. If you find nesting material, it’s best to call a pro and have them thoroughly inspect the property.

When nests are neat and well structured, mice are prosperous and have plenty of available resources. However, resources are likely scarce when nests are bare and messy or the pups are born without a nest.

Rodents may harbor and nest within areas of vehicles, like this breather box. This can cause major problems including electrical and engine failure.

Structured nests like this one in a vehicle air-intake box show adequate resource availability.

Unstructured nests are indicative of poor conditions for rodents which may include overcrowding, lack of food or other resources and overall unhealthy populations.

When nests are disorganized and incomplete, it could mean that resources are limited or overcrowded populations exist.

Mice born on a bare nest (or without nesting material) can mean poor resource availability

Mice born to bare nests or without a nest can indicate lacking resources, including nesting materials and even food.

Well structured nests indicate that rodent populations are thriving with adequate resource availability.

When nests are built from primarily one material, eliminating that resource may help reduce populations.

Disappearing Pet Food (or Other Food)

Dog and cat food make excellent rodent food as well. Disappearing food is a sure sign of a rodent problem. If your pet seems to be consuming more food than usual or is out of food and unusually hungry, you may have mice. Rodents will stuff their jaws with the high-in-protein pet foods and move them to a storage cache. Depending on the infestation, your pet’s food could disappear faster than average. Also, if you find any pet food mysteriously stored in an unusual area, you probably have rodents.

Many foods, including bird seed,  farm animal feeds, pet and animal foods, and even human food sources, make great meals for rodents. Any one of these or a combination could be the primary food source for an infestation. Locating and eliminating their access to such foods will help diminish populations and future infestations.

When birdseed and other foods are readily available, they interfere with bait placements.

One way how to tell if you have mice, is if food starts disappearing without explanation.

Easily accessible food should be made inaccessible to avoid contamination from mice

Peculiar activity from pets

If you have a cat or dog in your home, they may give you signs of a possible infestation long before the mice do! Suppose you notice peculiar or unusual behavior from your pet, such as anxiousness, fixation on a particular area in the home, concentration toward a fixed location, or unusual movement as if they are following or tracking something invisible. In that case, you might call a pro for an inspection. Pets may hear and smell an infestation well before you, or I do. Don’t ignore their signs.

Urine pillars

These are other definite signs of mice and usually indicate heavy or long-term infestations. Mouse urine easily mixes with dirt and dust wherever a mouse urinates. This will dry to form a yellowish, crusty mark with the ammonia smell. These pillars may be easy to see on a light-colored surface, especially an absorbent one. However, on darker surfaces, they may be harder to see. Ultraviolent light will cause them to glow and be highly visible. When in doubt, use ultraviolet light for a thorough inspection.


Some people are allergic to mice and other rodents, especially feces and urine. An infestation of mice may trigger such allergies, especially as the infestation grows. If you think you may have mice or rodents and have just not been feeling yourself, get to the doctor first, and then call us for an inspection as soon as possible.

Funky Odors

Where mouse infestations are present, so are their smells. Ammonia may be the first indicator. Early in the morning is the best time to notice their smell. The scent will be most potent before cooking, showering, or exterior air being moved into the house by opening and closing doors. However, your sense of smell toward it will be weakest since you have spent all night smelling it without knowing. A pro may be brought in early if necessary, but we would likely be able to smell it right away, no matter what time of day.

Damage to food items

When mice live with humans, they eat human food. Why? Because that is what’s available! When was the last time you bought mouse food? See? If you don’t keep mouse food around, they’ll eat your food!

Sometimes, they will chew into food packages, and we will find their signs quickly. Other times, they feed from crumbs or items we rarely use. Either way, if there are mice in the home, they are eating. If they’re eating, you’ll soon know it!

Mice will eat many foods leaving behind destruction and contamination in their wake.

When rodents are left to their own devices, they leave behind a wake of destruction and contamination in our food.

Grease Rubs

Mice have oil-producing glands which keep their coats in tip-top shape. Grease rubs result from animals’ frequent movement against an object, especially rodents, when their oily hair is rubbed against them. Once this oil is rubbed onto a surface, dirt, debris, hair, insects, and insect parts will attach to the oil and begin forming a dark rub mark.

If you find rub marks, it’s are a sure sign of rodent problems. These will occur near entrance areas, highly frequented areas, runways, and regularly used. Finding these means you need a professional pest control company to get involved immediately!

The frequent rubbing of a rodent against an area of travel leaves behind greasy rub marks.

Tracks and Drags

In even the cleanest of homes, there will be corners that have been missed somewhere. Dust and debris can accumulate in these corners and under furniture items. If a mouse infestation exists, their little paw prints and tail-drag marks will likely be present in those areas. A well-trained professional at Four Seasons Pest Solutions will notice these right away. Now you can too!

Damage to Furniture or Stored Items

With teeth that never cease growing, chewing all the time won’t wear their teeth away. When mice are present, their chew marks will be too. This may be on furniture, decorations, or stored items. A lot of damage can be done in a short amount of time!

I remember when I was a child, I had a pet hamster named Buddy. Buddy escaped his “cage” one night and meandered through the house. Mom was awakened by scratching noises echoing through the otherwise silent night. Unable to get back to sleep and still hearing the noises, she got up to investigate. She padded through the house, carefully listening to pinpoint the origin of the noise. Through the hall, past the bathroom, past the bedrooms, past the laundry… closer and closer, she came. Finally, she reached the dining room where ol’ Buddy was gnawing away at the new dining table they had just bought. Yes, one leg of that table became Buddy’s night-time chew toy.

The point? Where there are rodents, there is gnawing. When rodents gnaw, they produce noise. If you’re hearing that noise, it’s probably not your imagination. You need an inspection for rodents right away!

When rodents have access to furniture and household items, the damages they cause can be costly.

Alive or Dead Mice

This one should go without saying, but for those who might ignore the sign, DON’T! You may live with a light infestation for years unsuspectingly, but once you see a mouse, now you know. The heavier the population becomes, the more mice you will see. Interestingly most people never think of this, but where there are live mice, there are also dead mice. Things that live also must die, and mice don’t run off to the forest to do it. Wherever they are when death comes calling, that’s where they will take their last breath… even in your walls and attic!

Mice will die wherever they live. If that's in your walls or attic then so be it.

This dead mouse was photographed in a local attic near its burrow opening.

When populations are small, rodents may be seen little to none. Some customers say they saw something from the corner of their eye zipping behind an appliance or furniture. In heavier infestations, customers are more likely to report mice coming right out in the open in the middle of the day like no one is there. This is indicative of a heavy infestation. When the mice come up and introduce themselves to visitors, you are way past the need for control measures. It would be best to have serious restoration efforts to eliminate the rodents, sanitize the structure, exclude them from reentry, and repair the damages they caused.

Controlling What You Cannot See

The average untrained individual shouldn’t be surprised that they overlooked a rodent issue. These pests are naturally clever and often elude homeowners and business owners alike. Of course, seeing a mouse, especially during the day, could likely mean you have a mouse problem. Mice are nocturnal and rarely heavily active during the day. They also like to stay hidden from potential danger, including predators. Did I mention that they’re also relatively small? It’s no wonder many infestations go unseen, missed by the unsuspecting and untrained eye.

Couple their nocturnal nature, the instinct to stay hidden, and their small size with their ability to squeeze through tiny cracks and holes, and you have a very sneaky little creature that may be intent on using your home and eating your food in secret. Accessing hidden or infrequently used portions of a structure, mice will squeeze quietly in and take up residence. Infrequently accessed areas like the attic or crawlspace are great starting points for mice. Controlling what you cannot see is challenging. It’s hard to win a battle you did not know you were fighting!

That’s where the pros at Four Seasons Pest Solutions can step in and take over. Our rigorously, effectively, and professionally trained staff can spot the signs instinctively. Furthermore, we know precisely what must occur to begin elimination and prevention measures. It isn’t that difficult to stop an infestation when you have the experience. While we can’t specifically provide you with your own control adventure, we hope this article helps you somehow!

Areas You Might Find Rodents

As previously mentioned, it doesn’t take a massive crack, crevice, or hole for a rodent to enter, especially a mouse. Common areas where you might find a rodent would be an attic, crawlspace, basement, garage pantry, or detached structure away from the house, such as a barn or shed-like structure. Within a structure, rodents will also access wall voids, vents, vent pipes and duct work, stoves, under refrigerators, behind microwaves, and of course, in cabinets. It’s easy to imagine where a mouse could go if you consider their small size and start hunting. Nowhere is necessarily off limits for a rodent.

Vacation homes sometimes sit unoccupied for extended periods. Because of this, signs of mice are often found under pillows, beds, cushions, and other potential nesting areas. Their evidence will also be found in mattresses, living room furniture, and cabinetry. It’s common to see their signs within dryer vents left in disrepair.

Rodents can infiltrate commercial accounts through various means, such as hitching a ride on incoming products or entering through damaged or open doors. Even seemingly insignificant cracks, such as those found in concrete expansion joints, can provide easy access to rodents. These pests chew through rubberized expansion joints and burrow beneath the flooring. For those lacking the proper training, dealing with a rodent infestation can be daunting and exhausting.

Cracks, crevices and holes allow rodents easy access into a building.

Cracks, crevices, and holes allow rodents easy access into a building.

Should I Try Trapping if I Find Rodents?

At Four Seasons Pest Solutions, we believe what our mommas always told us, “An ounce of prevention is worth a pound of cure!” We like to apply this to rodent control as well. When you can prevent them, that is the best method. However, prevention does not stop what is already there. When a problem already exists, trapping measures are almost always a homeowner’s go-to method for control.

Trapping can be adequate for minor infestations, but significant infestations can lead to complications. Mice and rats can become “trap shy” and avoid traps, glue boards, and bait stations. This knowledge is then passed on to their offspring. Now there are generations of trap-shy rodents present, making control efforts difficult.

Additionally, trapping done incorrectly can cause failed trapping efforts. This happens when a rodent is initially trapped but gets loose from that trap. This rodent will not likely be trapped again. Instead, it  may urinate or defecate on traps to mark them “unsafe.” Other rodents will now also avoid the trap.

*Note: Always wear neutral nitrile or similar gloves when dealing with rodent trapping or baiting. You do not want the traps or bait to smell like you. That can discourage rodents from the devices. Additionally, this is a safety procedure for your health. To better understand various rodent species, visit our “Rodent Facts” page.

Trap Shyness is Real

Trap shyness can be prevented if proper procedures are followed. One must first assess the population density and then provide ample trapping devices. Next, baiting the traps and placing them unset (controlled baiting) will allow mice a few nights to become used to the devices as a food source and mark them as “safe.” After a few controlled baitings, it is time to set the traps to trigger when the mice access them. Once the mice return to feed, they will be trapped and killed nearly instantly. This prevents them from marking the traps as unsafe. Your controlled baiting has now made your trapping efforts fruitful!

If at any time you cease catching mice in your traps, it’s probably time to call in the pros here at Four Seasons Pest Solutions, that is, if you still have mice running around!

I Have Rodents. Should I Hire Professional Rodent Control?

Rodent infestations are a serious matter. The adverse effects of rodents on property and health are real. If you find signs of rodents, you should certainly be alarmed. This is the time to implement rodent control measures, whether you do it yourself or hire professional rodent control. As previously mentioned, do-it-yourself measures can be effective but when they aren’t, they can certainly cause more issues than they solve.

If you only have a few rodents, DIY just might be an option. If it’s more than a few, Four Seasons Pest Solutions can step in and implement rodent control measures that will not fail.

Whether it’s preventing an issue or discovering an infestation, Four Seasons has you covered.  Implementing a successful rodent control plan performing a rodent exclusion service, or both are viable and successful options that we offer. From infestation elimination and exclusion to decontamination and cleanup measures, Four Seasons Pest Solutions is a name you can trust for all your rodent needs. If you suspect rodents are invading your home or business, give us a call and we’ll get right to work!

For even more information, visit our page, “Rodent Central”.