Mice in Denver, CO – What You Can Do When Mice Infest Your Home!

The two most common species of mice in the Denver Metro area are Deer Mice and House Mice.

Deer Mouse in Cage

Deer Mice can be identified by their large ears, large black eyes, and white under bellies.

Adult House Mouse

House Mice have smaller ears & eyes and relatively hairless tails.








Deer mice tend to populate field areas (logs, tree trucks, etc) and open spaces while house mice prefer urban areas and corners of building to inhabit. Both can reproduce year-round with multiple large litters per year.

Fun Facts:

  1. The House Mouse can produce an average of 8 litters per year. That’s an average of 40-48 new mice per reproducing female!
  2. Daytime activity is a sign of a larger infestation.
  3. Different sized droppings can be a sign of a robust population – both adults and juveniles are present.

Diseases Carried by Mice

No matter the type of rodent, unless it’s a pet purchased from the local pet store, it is an uninvited guest. One you don’t want to live with. Mice can contaminate food prep areas in the kitchen, damage food packaging, and transmit disease.

While House Mice have been linked to numerous diseases (Leptospirosis, Lymphocytic Chorio-meningitis, etc), Deer Mice are primarily known for their ability to transmit the Hantavirus. The disease attacks the respiratory system and is typically spread through contact with items contaminated by feces and urine. It is important to use caution when cleaning up rodent debris and avoid skin contact or inhalation. You can learn more about the Hantavirus and other rodent diseases by visiting the Center for Disease Control’s website.

When It Is Time to Take Action

Exterior rodents will always be part of the ecosystem, but when they venture near buildings it may be time to address/manage the rodent population. Mice will take advantage of the shelter that a home provides from the elements and predators.

Here are a few signs of a rodent infestation:

  1. Droppings – mice droppings will be small pointed droppings with hairs or fibers in them. Old droppings will be dry and crumbly while fresh droppings will be moldable.
  2. Chew and rub marks
  3. Trails through insulation or pathways along ledges
  4. Nesting materials or burrows
  5. Running or scratching noises in the walls and ceiling spaces

Attic Insulation Damaged by Mice

Here are a few things you can do to help manage rodent populations:

  1. Eliminate food sources such as pet food, bird seed, unsecured pantry items or crumbs.
  2. Eliminate habitat such as brush piles, tall grass, dense shrubs, etc.
  3. Keep up on home maintenance to minimize possible entry points.

If mice do take up residence in your home, you may want to consider swift remediation. If rodents infest areas near your HVAC system, airborne pathogens can become a concern. They can also damage the integrity of your insulation – leading to lower efficiency.

Options to Consider When Addressing a Mice Infestation

  1. You can proceed with a one-time baiting/extermination. This may be ideal if you live in a multi-unit building and the HOA should/will take care of any ongoing rodent protection.
  2. You can proceed with an ongoing/quarterly maintenance plan. This is ideal for properties in areas of heavy rodent activity (rural areas, open spaces, etc). Ongoing maintenance keeps the exterior population under control and protects against them entering your home.
  3. One-time or ongoing extermination combined with exclusion services. This is ideal for homes with visible rodent entry points.

Mouse Entrance Hole in Exterior Wall of Building by a Utility Line

Let’s dive into the exclusion idea for a minute. Did you know that a young mouse can enter through a dime to nickel sized opening in a structure? This means you probably won’t be able to locate every possible entry point, but its still a good ideal to seal up those highways into your home. Some common spots that mice may use to enter include: damaged garage door seals, gaps in garage door jams, unsealed utility inlets (see photo above), crumbling brick, etc. They can also use some harder to reach entry points like sill plates and soffits.

What to Avoid When You Discover Mouse Activity in Your Home

  1. Never ignore the signs of an infestation. It’s always better and more cost effective to take care of the issue at the front end – before mice have taken over your home.
  2. Don’t rely solely on repellents or home remedies such as peppermint oil and sonic devices. Those may be helpful when done in conjunction with mechanical trapping or exclusions, but on their own they probably won’t provide lasting results. Mice will typically become accustomed to repellent devices in 3-12 months.
  3. Refrain from using steel wool or spray foam to exclude mice. Steel wool will rust and break down over time and both items can be chewed through by mice.

Who Can Help?

If you are looking for assistance, contact Whitmore Pest & Wildlife Control, Inc. Our goal is to address each property in a personal, individual manner to bring quality solutions to each situation. We would be happy to answer any questions you might have and schedule an inspection for your property.