Chapter 3: How Mice Get Into Your Home

By Pestech Pest Solutions

What attracts mice

Mice have no trouble making their way inside a home uninvited because they have all the physical skills they need to enter. For example, an adult mouse can squeeze through an opening that’s a little larger than the diameter of a pencil. If an opening isn’t quite large enough, a determined mouse can try to enlarge it with its teeth. Mice can chew through various materials, including plastic, vinyl, rubber, aluminum, wood and just about any paper product.

Mice are also highly skilled acrobats. They can climb and run along electrical wires, cables, tree branches and vines to help them access your home. Mice can also crawl up rough vertical surfaces, such as wood, brick or concrete walls. They can even swim and hang upside down. In other words, mice can easily get into your home, even if you built a moat around your house. But, this doesn’t mean they have a right to take over your home.

By understanding rodent capabilities and knowing what attracts mice, you can remove their entry points and reasons to return. In this chapter, we’ll show you where mice come from and why they headed for your house or business in the first place.

Where Do Pest Mice Come From?

Pest mice, such as house mice, deer mice and white-footed mice, typically come from outdoor nesting sites. As mentioned in Chapter 1, mice like to hide and live in piles of vegetation, inside tree hollows or burrows in the ground. Mice will also take up residence in corners of sheds or barns and may even build a nest in unused or broken yard equipment.

Although house mice aren’t as outdoorsy as deer mice or white-footed mice, they are highly adaptable and can spend their entire lives outside if they have no other option. However, house mice that stay in the wild typically have shorter lives than those that seek shelter in a building due to predation and harsh weather. Likewise, deer mice may live about five years in captivity but only a year in the wild due to the large number of predators that consume mice.

When pest mice get into a warm, safe house with a steady food supply, they don’t have to expend as much energy looking for something to eat as they would in the wild, and they can breed all year.

What Attracts Mice?

Mice are mostly attracted to food and shelter. If you offer either of these things in your home, you can attract mice.

You might provide food and shelter for mice without even realizing it because it’s very easy to do. If you have boxes of cereal in your kitchen, for example, or food scraps in the garbage can, mice can find a way to fill their bellies.

Regarding shelter, mice will seek a warm place to live and raise their young when the weather begins to get cold. This is why mice commonly enter homes in the fall and winter. They do not need anything fancy to call home and are happy to live in clutter, unused drawers or forgotten storage boxes.

What Food Attracts Mice?

Although mice are often depicted nibbling on cheese in cartoons and artwork, they actually prefer grains and seeds. When human fare is available, mice favor foods high in fat, sugar or protein, like nuts, butter, bacon and various sweets. Overall, mice will eat anything with some nutritional value, but a block of cheddar wouldn’t be their first choice.

Mice can easily live off crumbs, and they typically eat 3 grams of food per day or about 10% to 15% of their body weight. To give you an idea of how much food a mice eats daily, consider that a penny weighs about 3 grams. Mice also eat frequently and may visit different food sites 20 to 30 times each night.

By knowing what mice enjoy eating, you can choose effective bait for traps. For example, since mice love peanut butter, bacon and cereal, you might use any of these foods as bait. The Maryland Department of Agriculture also suggests caramel corn as an attractive mouse bait.

How Often Does a Mouse Need Water?

Mice only need about 1/5 ounce water a day to survive, and most of that water can be obtained from food. However, mice will drink water if it’s available, and a small plumbing leak is enough to keep them happy.

What Causes Mice to Come Into the House?

Mice are naturally curious and explore their environment, searching for food, other mice and warm, cozy places to build a nest. If mice smell food or detect other mice, they’ll enter your home however they can. They’ll go through openings such as:

  • Cracks in concrete or brick
  • Gaps around conduits for utility lines
  • Roof or wall vents without screens
  • Uncapped chimneys
  • Wall and roof joints without properly installed metal flashing
  • Poorly sealed air conditioning and heating ducts
  • Under doors or windows

Mice can also wander in through a door or window when you leave either propped open. It’s also possible for mice to hitch a ride in boxes, furniture or other items and get inside your home. Remember, mice can fit through a hole about the size of a dime, so you’ll have to look closely when examining your home for entry points.

How Do I Find Where Mice Are Coming Into My House?

Carefully check around the outside of your home for any cracks, gaps or holes mice can crawl through or that are 1/4 inch or greater in size. This includes looking at the siding, along eaves, around windows and doors, under the foundation and around utility lines. After you check the exterior of your home, inspect the interior for holes or gaps, especially near food sources. Check all corners, closets, cupboards and around appliances. If you find holes within your home, it’s essential to locate the main entry point so you can seal it up and prevent future infestations.

What Causes a Mice Infestation?

If mice find a food source and places to hide, they have no reason to leave your home. Mice also easily find each other, breed and quickly build a large population. A female mouse might have up to 10 litters a year of five or six mice. Young mice are ready to reproduce in six to 10 weeks. When mice live indoors, they don’t have to worry about predators or competing against other animals for food. Under the right conditions, mouse populations can explode.

What causes a mice infestation

Why Do Mice Keep Coming Back?

Mice will reinfest a home or building if they can still find openings in the structure to get inside. As mentioned earlier, mice aren’t picky eaters and can find shelter in just about any hidden spot. As long as they sense food in your home, they’ll enter through the same openings. Homeowners need to inspect their homes continually for cracks, gaps, holes and signs of mice even after eliminating an infestation.

Do Mice Leave on Their Own?

As long as mice have food and shelter in your home or business, they are not likely to leave on their own and go back into the wild where predators await, even when the weather gets warm again. Therefore, you’ll need to take action to control a mice infestation. At Pestech Pest Solutions, we’ll use our knowledge and experience to solve your mouse problem, no matter how big or small.

How Do You Stop Mice From Coming Into Your House?

Even though rodents are clever creatures with ninja-like skills, you can prevent them from entering your home or commercial building. You can install door sweeps to prevent mice from slipping underneath doors, for example, or repair weather stripping around windows to keep them out. You’ll also need to seal any cracks, gaps or holes outside of your home.

The next chapter will show you how to eliminate mice and keep them away.

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