Pesky rodents making themselves at home

By Irene Shonle
Director of Colorado State University Cooperative Extension in Gilpin County

1/13/2005 - The wet weather this last summer led to increased vegetation and insect levels, which in turn led to a big surge in the rodent population up here over the fall and winter.  I’ve received a number calls from homeowners who have never had mice in their houses before who are dismayed by these unwelcome furry visitors.  In older houses with many entry points, even mouse-sympathizers are on the warpath, and I’ve been dealing with a steady onslaught of mice here at my office in the Exhibit Barn.  In other parts of the county pack rats (also known as wood rats), voles, rabbits, ground squirrels and pocket gophers are making themselves at home.  Because of the number of calls, I will be holding a “Dealing with rodents” workshop at the Exhibit Barn on Thursday, January 27, at 7 p.m.  We will discuss identification, control and how to exclude rodents from your house.  But in the meantime, here are some ways to deal with the pesky critters.

Exclude them

  The long-term solution is to exclude mice from your house.  Seal up holes inside and outside the home to prevent entry by rodents. Prevent rodents from entering the home by checking inside the house for gaps or holes that are larger than a pencil could fit into. Potential rodent entry holes can be found inside, under, and behind kitchen cabinets, inside closets, around doors and under sinks. Seal the holes, using steel wool, lath metal or caulk. If you do not seal up entry holes in your home, mice will continue to enter.

  Prevent rodents from entering the home outside. Clear brush and grass from around the foundation of the home. Potential rodent entry holes can be found around windows and doors, between the foundation of your house and the ground, and around electrical, plumbing and gas lines. Seal possible entry holes with cement, lath metal, hardware cloth or sheet metal. Use flashing around the base of the house.

Eliminate food sources

  If you are experiencing particularly large numbers of mice, you may need to eliminate possible food sources. Keep food in thick plastic or metal containers with tight lids. Clean up spilled food right away and wash dishes and cooking utensils soon after use. Put pet food away after use and do not leave pet-food or water bowls out overnight. Use a thick plastic or metal garbage can with a tight lid. Keep compost bins 100 feet or more from the house. Keep grains and animal feed in thick plastic or metal containers with tight lids. In the evening, uneaten animal feed should be returned to containers with lids. If storing trash and food waste inside the home, do so in rodent-proof containers, and frequently clean the containers with soap and water. Dispose of trash and garbage on a frequent and regular basis, and pick up or eliminate clutter.

Eliminate nesting sites

  Eliminate possible nesting sites outside the home. Elevate hay, woodpiles and garbage cans at least one foot off the ground. Move woodpiles 100 feet or more from the house. Get rid of old trucks, cars and old tires that mice and rats could use as homes. Keep grass and shrubbery within 100 feet of the home well trimmed.

  Exclusion is the best long-term method, but it doesn’t help necessarily with the mice that are in your house right now!  Ways to get rid of those mice include:

Trapping

  Trapping has several advantages: (1) it does not rely on hazardous poisons; (2) it permits the user to view his or her success; and (3) it allows for disposal of the mice, thereby eliminating odor problems from decomposing carcasses that may remain when poisoning is done within buildings. The simple, inexpensive, wood-based snap trap is available in most hardware stores. The easiest bait to use is a pea-sized smear of peanut butter.  Set traps close to walls, behind objects, in dark places and in locations where mouse activity is seen. These traps are inexpensive enough that some people who are too squeamish to empty and reuse a trap simply throw the entire mouse and trap away.

  Glue traps are not recommended. These traps can scare mice that are caught live and cause them to urinate. This may increase your risk of being exposed to disease. Also, because the mouse dies very slowly, they are not considered humane.

  Live trapping and releasing may seem like the most humane solution, but it poses several problems. What do you do with the rodents once you’ve caught them? You may be surprised to know that in Colorado, you may not release them into the wild without a permit from the Department of Wildlife. If you do get a permit and release them, the story still might not have a happy ending. Disoriented and afraid, released mice may be quickly snapped up by predators, or be unable to find a place to live -- or the mouse may introduce disease into wild populations.  Therefore, a quick kill may actually be the most humane method to deal with unwanted mice.

Poison

Poisons have undesirable side effects, such as the accidental poisoning of dogs, cats, birds and other animals that eat the bait. Another problem is that you never know where a poisoned rodent will die. If it dies in a wall, you’re stuck with its smell for weeks. But, for many people, this is the easiest solution. These are easily found at hardware stores.

The Gilpin County Cooperative Extension office is located at the Exhibit Barn, 230 Norton Drive, Golden CO 80403 (right next to the Gilpin Community Center). Website: www.coopext.colostate.edu/gilpin, phone: 303-582-9106, email: irene.shonle@colostate.edu

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Colorado State University Cooperative Extension provides unbiased, research-based information about, horticulture, natural resources, and 4-H youth development. As part of a nation-wide system, Cooperative Extension brings the research and resources of the University to the community.