How to get rid of mice & keep them out of your home:
Six effective steps to getting rid of mice & keeping them out. This article describes the signs of a mouse infestation and continues by describing how mice get into buildings, where they like to hang out, and how to get rid of mice and keep mice out of your apartment or home.
We describe both effective and some ineffective or otherwise not-recommended mouse control measures and we include real-world practical tips based on seventy years of field and lab experience with mice
This article series discusses how to find where animals are getting into your building and how to keep them out, including bats, birds, rats, mice, and squirrels and even raccoons. This article series focuses on removing pet or other animal odors from buildings due to pet urine, pet feces, wild animal urine, or even human urine on and around buildings or on clothing and other soft materials.
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Mice Indoors: Let's Get Rid of the Mouse in the House (Many Mad Mice Are Not so Nice)
[Click to enlarge any image] Above is a dead mouse found in a building wall cavity during a home inspection.
[Click to enlarge any image]
While above in a more subtle (at least visually subtle) clue indicating rodent infestatino, we illustrate finding mouse urine and feces in building insulation. Here are mouse-specific tips on how to get rid of mice in your home and how to keep them out.
How do I Know if I've Got Mice in My Apartment or Home?
It's helpful to know that mice living in your apartment or house generally occupy a surprisingly-small area, sometimes less than 50 feet in diameter.
A sip from a dripping sink faucet and a nibble on fallen Kibble is enough to keep a mouse family in fat city for quite a while.
How do you know if you've got a mouse problem? You may not see the mice personally, but they're not very discriminating about where they poop and they never clean up after themselves.
Or as you'll read later in this article, sometimes the mice get quite brazen, stomping their tiny feet across the living room or leaping into your cereal bowl. Really!
Early in my mouse-fighting career (which has been intermittent over seven decades) I played with cute pink and hairless blind baby mice nesting in a wooden Coca Cola bottle crate in the basement of our Dunsville Virginia farmhouse.
A little nest of shredded newsapaper formed their comfy home but Mom objected when I elevated the status the infants to upstairs. Later that day mom took the pink-ones for a swim in the Rappahannock.
Later my parents put mouse poison in the basement to create an island of mouse-death of sufficient diameter that we no longer found their tiny footprints in the Jello.
Watch out: today we no longer recommend such hands-on attention nor direct contact between you and your mice. (Mills, 1995)
Six Steps to Effective Mouse Management:
How to Get Rid of Mice Indoors
In the middle of my mousecareer (not the Disney type) Katheren L., a Fishkill attorney called me to demand mouse-action. After months of tolerating mouse droppings throughout her home, that morning she'd sat down still half-asleep to begin a dozy-breakfast in the kitchen.
Opening a box of Corn Flakes she began to pour it into her cereal bowl. A mouse lept out of the cereal box right into the milk! That was the final straw. Here are the mouse-removing steps that we implemented:
Remove the mouse-food: clean up spilled pet food or those carrot ends you dropped in the kitchen. Keep boxed or bagged mouse-edible food that is not in your referigerator sealed in secure containers such as jars or heavy, tight-lidded plastic containers.
Mice are particularly attraced to homes with pets, perhaps because pet food is so readily available. (Langton 2001)
close off openings through which mice are entering your home. It's tough to find all of these, especially if your home includes a hard-to-access crawl space but close as many openings as you can.
Take a look around areas wher you are seeing mouse droppings.
Under the kitchen sink you may find pipe passages that give mice an easy access from basement or crawl space into the main food area of your home. Even a vert tiny hole, perhaps just a half-inch across, is enough for some mice to shinny into your apartment.
Below are more examples of mouse access points into a building. My friend Paul Galow puts his mouse traps right next to the mouse-doors he's found in his home (below left): in this case a heating baseboard pipe opening in a wall that abuts a utility room and crawl space.
Below you can see examples of harder-to-find mouse access openigns around the heating or cooling ducts in an older home.
Watch out: a mouse or rat infestation of the air conditioning or heating ducts can leave urine and fecal waste that may contain pathogens that could make someone sick. Below you see the remains of a mouse in the air handler of a central air conditioning and heating blower compartment.
I often find dead mice in this location, an event that suggests that no one has been changing air filters nor cleaning the unit for a time.
At CRAWL SPACE SAFETY ADVICE we describe a Hanta Virus risk encountered in crawl spaces where there has been mouse or rat activity.
Poison the mouse-pests: using mouse baits or poisons is effective and if properly done can be safe for children or pets.
You cannot possibly kill all the mice in your neighborhood, but you can create an island of mouse-death around your apartment or home by strategic placement of these mouse killing products.
The Mouse Killer poison in the white pouch shown at above right is a Real-Kill product that has the advantage that you don't have to handle or touch the poison directly. The mice use their cute tiny noses to sniff out this bait and their sharp nasty little teeth to gnaw their way in to their fatal reward.
Below are two examples of putting down "bait" or mouse or rat poison.
I prefer types of poisons that don't encourage the mouse to die in and stink up the walls and ceilings of my home. Some poisons take effect when the mouse steps outside to its local pub for a drink.
Watch out: to protect children and pets from possible illness or death from eating mouse or rat poison be sure that you follow the manufacturer's instructions for placing the bait or poison.
Trap and and release or trap and kill the mice:
Personally I prefer giving a quick painless death to my mice (Paul's conventional mouse trap shown earlier above and in close-up just below). Paul uses peanut butter as mouse bait, or chees, or as some experts suggest, a cotton ball dampened with water - an innocent bait that's good for about a day.
Little plastic mouse-hotels (they check in but they can never leave) also work but having seen a few gnawed-off legs and frantic attempts to gnaw out of a plastic mouse-hotel, I don't find those methods very charming even if they're quite effective.
My friend Barb W. (since our break-up she's changed her name to Adrienne - don't ask me why) left mouse hotels in her Rhinebeck NY home where spilled dog food was inviting mouse conventions each week.
The idea was that the mouse would snuggle into the little plastic mouse-box, the mouse door slams shut, and you're supposed to carry the mouse over to your neighbor's yard to release it.
But if you leave the mouse in her hotel for days it's a different story - it becomes not trap and release the live mouse, but trap and toss a stinking dead one.
The trapped mouse had gnawed the plastic mouse trap enough to make a hole in it but the mouse didn't live long enough to gnaw a hole big enough to escape.
Or maybe it died from eating those plastic chips. It was up to me to take the mouse hotel outside, cross the street to a distance of at least 50 feet from Barb's house, open the mouse-hotel latched door, and sling the dead mouse into the weeds. Ick.
Cats vary in their ability to keep the mouse population down.
We certainly kept cats in the barn where they stayed fat on mice when I was a kid. But in our country house (Goochland County, Viriginia) Suki, our girl-cat, wasa terrifed of mice and ran like hell whenever she saw one.
What about glue traps for mouse control? Below we see an entire family of mice of various sizes found their last meal in a glue trap placed in a building in northern Minnesota.
Watch out: the New York Times has a nice mouse control article that supports our disaffection with glue traps for mice, including a more authoritative opinion that we quote:
"Glue or live traps should also be avoided, according to the Centers for Disease Control and Prevention [US CDC], as they can scare mice and cause them to urinate.
'Since their urine may contain germs, this may ioncrase your risk of being exposed to disease,' according to the C.D.C. Rodents trapped by glue also die a slow death, usually from hypothermia, ..." - Michelle Higgins, "Of Mice and Apartment Sales", The New York Times, p. RE B-1, 14, 8 Nov. 2015.
Really? In my opinion this is nonsense: any trapped mouse may pee and the mice pee where they please, whenever they please hen they're not trapped too. They pee and poop all over the place.
Watch out: Running a household vacuum cleaner (a non-HEPA rated unit) risks areating unhealthy or contaminated dust and pathogens in mouse urine and feces regardless of whether you touch them, and probably at a greater health risk.
Don't do that. Do use disinfectant sprays or cleaners to clean up mousy surfaces and do wear gloves or other protective gear as appropriate. You don't need to carry the mice bodies to their funeral in your bare hands.
Repel the rest of the mice: using electronic devices you might have success with this non-toxic mouse repellent strategy.
My experience with ultrasonic or sonic mouse and rodent repellilng machines has been mixed at best and ineffective at worst.
Really? At the Rhinebeck mouse in the house convention I sat watching the most-expensive, biggest electronic mouse repeller that Barb could buy.
A cute little mouse walked right up to the electronic mouse repeller and sniffed at it. Either that mouse was stone deaf or ... no, readers, the electronic mouse-repeller was indeed plugged in and turned-on.
Other mouse repellent methods (besides the silent scream of the mouse siren) are mouse repellent such as Shake-Away granules or Stay-Away rodent pouches. From my own field tests I report that mice also don't have a high opinion of mothballs.
Bring in the Mouse-Terminator: you won't really need to bring in a robo-cop nor Arnold Schwarzenagger, but you may need to hire a professional pest exterminator, particularly if you don't feel up to the job yourself, or if you have tried the steps we list above and you've still got a mouse-invasion going on.
Be sure that the pest control professional you hire is licensed.
Mouse Control Research & Resources
Photo: the common house mouse or Mus musculus, source: U.S. CDC who in turn credit this photo to Larry Masters, cited below.
Abbott, Ken D., Thomas G. Ksiazek, and James N. Mills. "Long-term hantavirus persistence in rodent populations in central Arizona." Emerging infectious diseases 5, no. 1 (1999): 102.
Anticimex®, RATS and MICE - UNWANTED GUESTS [PDF], general advice and entry points to plug, Antiximex®, Sweden, Website: www.anticimex.se retrieved 2020/01/10, original source: https://www.sssb.se/en/wp-content/uploads/sites/2/Facts_ratsmice_ENG.pdf
California Department of Pesticide Regulation, FREQUENTLY ASKED QUESTIONS ABOUT RODENTS & RODENTICIDES [PDF] (2015) Department of Pesticide Regulation, Pest Management & Licensing Branch, retrieved 2017/11/08,original source: http://www.cdpr.ca.gov/docs/dept/factshts/faq_rodents_rodenticides.pdf, retrieved de-novo 2022/09/01, original source http://file.lacounty.gov/SDSInter/acwm/235831_FAQRodentsandRodenticides.pdf
Childs, James E., Thomas G. Ksiazek, Christina F. Spiropoulou, John W. Krebs, Sergey Morzunov, Gary O. Maupin, Kenneth L. Gage et al. "Serologic and genetic identification of Peromyscus maniculatus as the primary rodent reservoir for a new hantavirus in the southwestern United States." Journal of Infectious Diseases 169, no. 6 (1994): 1271-1280.
Chitty, Dennis, and Henry Neville Southern, eds. Control of rats and mice. Vol. 1. Clarendon Press, 1954
Fischer, O., L. Matlova, J. Bartl, L. Dvorska, I. Melicharek, and I. Pavlik. "Findings of mycobacteria in insectivores and small rodents." Folia Microbiologica 45, no. 2 (2000): 147-152.
Glass, Gregory E., Timothy Shields, Bin Cai, Terry L. Yates, and Robert Parmenter. "Persistently highest risk areas for hantavirus pulmonary syndrome: potential sites for refugia." Ecological Applications 17, no. 1 (2007): 129-139. Abstract:
Interannual variation in the number of cases of human disease caused by hantaviruses in North America has been hypothesized to reflect environmental changes that influence rodent reservoir populations. This hypothesis postulates that when cases are rare reservoir populations are geographically restricted in patches of suitable habitat. Identifying these sites, which is needed to test the hypothesis, has proven to be a challenge.
Satellite imagery of the U.S. Southwest has shown associations among the likelihood of human hantaviral disease and increases in the rodent populations, as well as increased prevalence of Sin Nombre virus (SNV) in rodent populations.
In this study we characterize local areas that had environmental signatures that persisted as predicted highest risk sites for human disease through much of the 1990s. These areas represent a small percentage (0.3%) of the region. Exploratory analyses indicate that these areas were not randomly distributed, but were associated with certain landscape characteristics.
Characteristics of elevation, slope, aspect, and land cover were associated with persistent high risk. Using multivariate Poisson regression to control for confounding effects, sites with deciduous- or mixed-forest land cover on moderate to steep slopes (>5°) above 2130 m elevation were associated with increasing numbers of years at highest risk. These are candidate locations for refugia. Sites associated with cleared ground or shrubland were less often associated with high risk compared to reference conditions.
The seasonal patterns of vegetation growth in persistently high-risk areas were compared to matched locations using MODIS (moderate resolution imaging spectroradiometer) NDVI (normalized difference vegetation index) during a time of a severe drought in the region from 2002 to 2004.
Despite the drought and regardless of land cover, the NDVI in persistently highest risk areas had an early onset, with significantly higher levels of green vegetation that lasted longer than at comparable sites.
These observations identify locations that can be monitored for the abundance of P. maniculatus and presence of SNV. If these sites are refugia, we predict they will be occupied by infected deer mice when other monitored sites are unoccupied.
Read More: http://www.esajournals.org/doi/abs/10.1890/1051-0761(2007)017[0129:PHRAFH]2.0.CO;2
Langton, S. D., D. P. Cowan, and A. N. Meyer. "The occurrence of commensal rodents in dwellings as revealed by the 1996 English House Condition Survey." Journal of Applied Ecology 38, no. 4 (2001): 699-709. Summary 1. The presence of commensal rodents was assessed in the 1996 English House
Condition Survey (EHCS). Logistic regression techniques were used to identify the key
factors that might determine the susceptibility of dwellings to infestation.
2. The overall percentages of dwellings that were infested, weighted to allow for the
more intensive sampling used in certain categories of dwellings, were 1·83% for mice
Mus domesticus, 0·23% for rats Rattus norvegicus living indoors and 1·60% for rats
living outdoors. These figures excluded vacant properties, properties with some
commercial use, and purpose-built flats, as these groups showed different patterns of
infestation and were therefore excluded from the logistic regressions.
3. The prevalence of both rats and mice was significantly greater for dwellings where
pets or livestock were kept in the garden.
4. Dwellings classed as unfit for human habitation were more likely to be infested with
mice.
5. Dwellings in areas of low-density housing had a significantly higher prevalence of
both rat and mouse infestation. This probably reflects the general suitability of the rural
environment for commensal rodents.
6. Older properties had a relatively high prevalence of rats. This may be because their
mature gardens provided suitable habitats for colonization. Once other confounding
factors were taken into account, the age of the property did not influence the rate of
infestation by mice.
7. Dwellings in areas with substantial problems, such as dereliction, litter, vacant properties
and unkempt gardens, had a significantly higher prevalence of rats and mice.
8. This study reveals the value of applied ecological techniques, including logistic
regression of presence–absence data, in understanding the distribution of commensal
rodents in relation to dwellings, with the prospect of more effective management
practices being developed as a consequence.
Mills, James N., Ph.D., James E. Childs, Sc.D., Thoas G Ksiazek D.V.M. Ph.D., C.J. Peters, M.D., METHODS for TRAPPING and SAMPLING SMALL MAMMALS for VIROLOGIC TESTING [PDF] (1995) U.S. Centers for Disease Control and Prevention, retrieved 2020/01/10 original source: https://www.cdc.gov/hantavirus/pdf/rodent_manual.pdf
Excerpt: This manual is intended as a guide for those persons performing ecologic and epidemiologic studies involving populations of rodents which are potentially infected with
hantavirus. However, the procedures outlined are appropriate for any study of smallmammal populations that may harbor an infectious zoonotic agent capable of causing
severe disease or death.
Mills, James N., Terry L. Yates, James E. Childs, Robert R. Parmenter, Thomas G. Ksiazek, Pierre E. Rollin, and C. J. Peters. "Guidelines for working with rodents potentially infected with hantavirus." Journal of Mammalogy 76, no. 3 (1995): 716-722. Abstract:
Because of the high morbidity and mortality associated with hantavirus pulmonary syndrome and the possibility of aerosol transmission of hantaviruses, persons handling known reservoir species in the field, laboratory, or classroom should take special precautions to minimize the risk of infection.
We provide specific guidelines for personal safety while trapping, handling and releasing, transporting, sampling, and performing necropsy on potentially infected rodents or teaching field classes in areas occupied by reservoir species.
Special consideration should be given to respiratory protection, choice and use of disinfectants, decontamination of instruments and traps, proper disposal of infectious wastes, and preservation and shipment of samples intended for hantavirus testing.
Precautionary testing of wild rodents used to start laboratory colonies is recommended. Although we specifically address hantaviruses, the procedures described are applicable for any study of populations of small mammals when an infectious zoonotic agent transmissible by aerosol and capable of causing high morbidity and mortality is involved.
Pearson, Dean E., and Ragan M. Callaway. "Biological control agents elevate hantavirus by subsidizing deer mouse populations." Ecology Letters 9, no. 4 (2006): 443-450.
Excerpt: Mice can squeeze through holes the size of a biro, typically living and breeding under
floors, in cavity walls, ceiling voids and behind skirting boards where they are able to build
small nests.
They are very agile and excellent climbers.
Although mostly nocturnal, mice can be seen
during the day. They are inquisitive creatures and will feed from numerous sources, often
nibbling small amounts of a wide variety of foods.
Rowe, F. P., T. Swinney, and R. J. Quy. "Reproduction of the house mouse (Mus musculus) in farm buildings." Journal of Zoology 199, no. 2 (1983): 259-269. Abstract:Z
Live and kill traps were used to remove House mice living in granaries, mixed-food stores, dairy units and ancillary stores on farms. Structural weaknesses were common to all buildings. Cavities in walls, in particular, provided favourable living and nesting quarters for mice and were rapidly exploited.
The body-weight structure and reproductive traits of the populations in the different habitats were compared.
The onset of maturity, in both sexes, was closely related to body-weight increase in the 10 to 14 g range. Breeding, unlike that in most out-door populations in temperate climates, continued throughout the year. Ancillary buildings holding limited food supported small reservoir populations.
Mice inhabiting dairy units containing pelleted cattle feed tended to be heavier than those sampled elsewhere and females in the units produced the largest litters.
Reproductive performance on farms was intermediate between that of mice occupying urban buildings and corn ricks. There was evidence that environmental and behavioural factors were operating to limit increase in numbers in the dairy units.
U.S. CDC, INTEGRATED PEST MANAGEMENT: CONDUCTING URBAN RODENT SURVEYS [PDF] (2006) U.S. Centers for Disease Control and Prevention, Atlanta: US Department of Health and Human Services; 2006. retrieved 2020/01/10 original source: https://www.cdc.gov/nceh/ehs/docs/ipm_manual.pdf
Excerpt: This manual is for classroom use and for field
training of program managers, environmental health
practitioners, inspectors, outreach workers, and others
who work in community-based rodent integrated pest
management programs. The manual is also a reference
for survey techniques and for the preparation of reports
and maps.
retrieved 2020/01/10 original source: https://www.cdc.gov/rodents/prevent_infestations/seal_up.html
Yates, Terry L., James N. Mills, Cheryl A. Parmenter, Thomas G. Ksiazek, Robert R. Parmenter, John R. Vande Castle, Charles H. Calisher et al. "The Ecology and Evolutionary History of an Emergent Disease:
Hantavirus Pulmonary Syndrome Evidence from two El Niño episodes in the American Southwest suggests that El Niño–driven precipitation, the initial catalyst of a trophic cascade that results in a delayed density-dependent rodent response, is sufficient to predict heightened risk for human contraction of hantavirus pulmonary syndrome." Bioscience 52, no. 11 (2002): 989-998.
Zeitz, Paul S., Jay C. Butler, James E. Cheek, Michael C. Samuel, James E. Childs, Lee A. Shands, Richard E. Turner et al. "A case-control study of hantavirus pulmonary syndrome during an outbreak in the southwestern United States." Journal of Infectious Diseases 171, no. 4 (1995): 864-870.
Watch out: in addition to their common role as allergens, animal feces, urine, even hair can offer serious health hazards including from various pathogens: bacteria, viruses, even possibly rabies.
Watch out: also for wild animal bites, bacterial and viral hazards when entering confined spaces where invaders are or have been present. The author (DF) became temporarily ill after (foolishly) working in a "clean looking" crawl space that later he realized had a heavy contamination of fecal and urine contaminated mouse dust. Bat and rodent droppings as well as bird droppings can be a source of a pathogen potentially dangerous to humans, the fungus Histoplasma capsulatum.
Watch out: before sealing up a hole in a soffit or wall where squirrels or bats are entering your building, make sure the animals are not going to be trapped inside where they will be mad, frightened, hostile, even dangerous (like a rabid raccoon), or ultimately dead and another source of stink.
Reader Comments & Q&A
Question: mouse infestation in public housing
Hello, my blind brother lives in a public housing apartment building for Elderly & Disabled in Kansas. He has had an ongoing problem with lots of mice. I have set traps and caught/killed 19 mice withing last 2 weeks alone! The last one, I caught, when it was sitting in the middle of his stove on top.
If he would have been in there and got close to it, he could have been bitten. The landlord has had pest man come through building to set glue traps and he is still locating all the plaaces that they get into the building. Any help is greatly appreciated thanks - Anonymous by private email 2017/05/12
Reply:
Mice will return, even if exterminated, if there is attrative food for them to eat. So in addition to traps, poisons, and cleaning up spills, be sure that all mouse-attracting food is stored in sealed containers.
My best advice is in the GET RID of MICE article above, please take a look, then ask whatever further you like.
Watch out: Beware that besides biting, mite fecals and urine can pose a health hazard. So some cleaning may be in order too.
You should also be able to ask for help from your health department.
Question:
use of peppermint oil and ammonia to repel animal poopers and pests
(Sept 23, 2012) Anonymous said:
I have heard that peppermint smell repels mice and squirrels. Is that so?
Reply:
Good idea Anonymous. Peppermint is better than trying to scatter mothballs apart as using mothballs for animal repellant is an illegal application and can cause other building odor or health problems.
A number of animal repellant products do indeed contain peppermint oil, such as some deer and cat repellants. ther mixtures for similar applications mix oils of peppermint, geranium, sage, lavender, eucalyptus, lemongrass etc.
There are other specific animal repellent sprays and products sold at home and garden suppliers, often targeted to specific animals: coyote urine, for example.
I've also tried pouring a bit of ammonia (or bleach but never BOTH at once) onto an area on a walkway or stair where a cat kept urinating.
Outdoors where our neighbour's cat had decided that our stone walkway was a nicer toilet than its own yard we had such an accumulation of cat poop that besides cleaning up that mess we needed to encourage Cheeto to find a different relief site.
After cleaning up the mess we poured household ammonia around the poop area. That worked.
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