Mice in Eastern Ontario

Image by karin_van_Duke from Pixabay

Mice are mammals in the family rodentia and genus mus.  The two most common species of mice in Canada are the house mouse and the deer mouse.  Both species reside in Eastern Ontario and are found in our locale.   They may invade your home in search of food, water or shelter.  In the fall, as winter approaches, they often search for the warmth our homes provide.  In the wild, some mice like to create burrows underground while others choose nests on the surface.

The house mouse has large ears and is light brown to dark grey, with a lighter colour on its belly.  It is often found in urban areas (hence the name house mouse).  The deer mouse is brown or grey with a white belly and white feet.  The white colour on the underside of its tail is an easy way to spot a deer mouse.  The picture on the left is a house mouse and on the right, a deer mouse.

The house mouse – next to humans, the house mouse is the most populous species on Earth and is found mostly in urban centers.
The deer mouse – named for its similarity to the colouring of deer with the darker back and sides and the white underbelly, feet and underside of the tail.

The life of a mouse is very hazardous averaging two to three months.  They can, however, survive as many as 20 months in the wild and two or more years in captivity.  Typically, mice will breed from early Spring to late Autumn.  In the right environment, mice can breed year round.  If we crunch some numbers we can see why it’s important to call in pest control as soon as possible if you see any sign of mice.  Lets say that our example mouse is born in late March.  By six weeks old she is able to reproduce and has her first litter of pups May 1st.  Mice can have anywhere  between 3 and 14 pups per litter but the average is 6 to 8.  For our number crunch, lets use 7. If she has a litter every month to two months by the end of November she’s had between 5 to 10 litters with between 35 to 70 offspring.  What if our mouse is super healthy with an optimum environment (like your unused attic)?  Using the maximum for our numbers she can have 10 litters with up to 14 per litter, that 140 mice.  If you start to factor in her daughters, granddaughters and great great granddaughters you have a real problem! 

Image by Fritz_the_Cat from Pixabay

Listen for scratching or scampering sounds in the walls at night, signs of gnawing or chewing and damage to food packages.  Mice are rodents so their teeth never stop growing and they are constantly gnawing to keep them sharp.  Other signs that our mouse is proliferating will include droppings and urine (you’ll know – its a very strong scent), burrows, holes in and around foundation walls, and tracks on dusty surfaces.  If you have a pet cat they may also bring you “gifts” or scratch at cupboard doors and hidden corners.  These are all signs you need to tackle the problem quickly, before you have a severe infestation.


Mice are so cute though!  Why do I need to worry about them?  Well, aside from the numbers when they are left to breed indiscriminately, mice carry diseases.    They spend the night running around your house spreading germs from one place to another.  You wash your hands after you touch the floor or use the washroom, mice don’t.

Deer mice in particular carry a dangerous pathogen (disease causing bacteria, virus or other micro-organism) called the Sinn Nobre virus.  Not all deer mice carry the virus, but those that do spread it around in their urine and feces.  Inhalation of the dried excreta can cause Hantavirus pulmonary syndrome.  Hantavirus pulmonary syndrome causes the lungs to decrease in function and gradually fill with fluid.  In Canada, most Hantavirus pulmonary syndrome cases occur in the western provinces of British Columbia, Alberta, Saskatchewan and Manitoba.  There have been no recorded cases of Hantavirus pulmonary syndrome in Ontario.  

Hantavirus pulmonary syndrome is not transmitted from person to person. It is typically inhaled when dried urine and feces is swept into the air by cleaning areas that are infested with mice and haven’t been  It is important to handle deer mice (or all mice if you aren’t sure of the species) with gloves.  If the mouse is infected with the Sin Nombre virus, it will be in their blood, urine and feces.  Wash your hands thoroughly with dish soap to destroy the virus and dispose of droppings quickly.


The key to controlling mouse problems in your home is prevention.  Rodent proof your home and make your yard less appealing using the tips below.

Rodent proof your home

Image by Merio from Pixabay

Mice can squeeze through cracks as small as a dime so its not always easy to eliminate entry points.  The most common spaces are the worn spots under doors.  The larger gap created by the wear of the threshold can be enough to let them in.  Here are some ways you can stop rodents from entering your home.

      • Use weather stripping on the bottom of doors and around window openings to block access to the house.
      • Regularly examine your foundation for cracks and patch any you find.
      • Gaps around pipes can be stuffed with steel wool before you caulk or plaster.  Mice can chew through the plaster, but not the steel wool.
      • Check dryer vents, attic vents and soffits for gaps and cover the openings with fine mesh metal screening.  This will also discourage other animals and birds from entering.

Make your home less appealing to rodents

      • Remove clutter from around your house and garage.  This removes the cozy nesting sites they prefer.
      • Keep the grass around the house and garage trimmed and remove tall weeds.
      • Use garbage containers with tight-fitting lids.
      • Raise woodpiles off the ground (about 30 cm or 1 foot should do) and place them away from the house.
      • Never put fatty or oily food waste, eggs or milk products in the composter.
      • Place your composter on a layer of heavy metal mesh to prevent rodents from tunneling up underneath
      • Eliminate sources of water from leaky taps, sweating pipes and open drains.
      • Keep your kitchen clean.  Store dry food and dry pet food in metal or glass containers (they can chew through plastic)

If these furry pests become problematic, call a licensed professional exterminator;  may we recommend Enviro-Guard Plus?    Contact us  here.