Rodent Control for Homeowners

Signs of Rodent Infestation

Inspect your yard and home thoroughly. If the answer to any of the following questions is yes, you may have a rodent problem.

  • Do you find rodent droppings around dog or cat dishes or pet food storage containers?

Photo

Droppings of house mouse (left), roof rat (center), and Norway rat (right). Photo by William Gelling.

  • Do you hear noises coming from the attic just after dusk?
  • Have you found remnants of rodent nests when dismantling your firewood stack?
  • Does your dog or cat bring home dead rodent carcasses?
  • Is there evidence rodents are feeding on fruit/nuts that are in or falling from the trees in your yard?
    Photo from www.ocvcd.org
  • Do you see burrows among plants or damaged vegetables when working in the garden?
  • Do you see rats traveling along utility lines or on the tops of fences at dusk or soon after?
  • Have you found rodent nests behind boxes or in drawers in the garage?
  • Are there smudge marks caused by the rodents rubbing their fur against beams, rafters, pipes, and walls?

Photo from www.msmosquito.org

  • Do you see burrows beneath your compost pile or beneath the garbage can?
  • Are there rat or mouse droppings in your recycle bins?
  • Have you ever had to remove a drowned rat from your swimming pool or hot tub?
  • Do you see evidence of something digging under your garden tool shed or doghouse?

Some rodent infestations can easily be managed by homeowners. Below are a few steps to manage rodent pests. Note that the ORDER in which these steps are taken is critical!

1. IDENTIFY THE TYPE OF RODENT

  • The stocky Norway rat builds burrows along building foundations, beneath rubbish, or in woodpiles. Indoors they tend to remain in basements or on the ground floor.
  • Roof rats are agile climbers with a tail longer than their head and body. They usually live and nest above ground in shrubs, trees, or dense vegetation. Indoors they favor attic spaces, walls, false ceilings, and cabinets.

Use the graphic to help determine what kind of rodent you have. This may not be easy, and you may need to consult with a professional.

IllustrationFrom Bjornson, B. F., and C. V. Wright. 1960 (revised). Control of Domestic Rats and Mice. Center for Disease Control, USDHEW, Public Health Service Pub. 563.

IllustrationFrom Bjornson, B. F., and C. V. Wright. 1960 (revised). Control of Domestic Rats and Mice. Center for Disease Control, USDHEW, Public Health Service Pub. 563.

2. REMOVE FOOD SOURCES

Remove or eliminate the following:
• Pet food left out at night
• Unharvested fruit, nuts, vegetables
• Bird seed
• Uncovered garbage
• Grass or plant seeds
• Poorly maintained compost piles
• Dog droppings

3. EXCLUDE RODENTS FROM HOMES AND BUILDINGS
First, find out where they are entering your home. Basic tools are: the Rule of Thumb for
measuring (if your thumb fits, a rat can fit and if your pinky finger fits, a mouse can fit) and a flashlight. Check any work that was done after the original construction for holes or gaps. To find entry points in attics or crawlspaces:

• Check during the day and turn off lights
• Inspect where you see daylight entering
• Check vents and where pipes or cables enter the house

Once you have determined entry points, use hardware cloth, rust-proof/stainless steel
wool, metal flashing or plaster patching kits as appropriate to close off these areas.

4. ELIMINATE RODENTS

Trapping
Snap traps are recommended. Always use mouse traps for mice and rat traps for rats. Depending on the kind of rodent, you will have to select the right placement of traps and you might need to place food on the trap and not set the trap (also known as pre-baiting) for two to three nights in a row. Bait effectively with peanut butter and oats.

Baiting
To prevent rodents from dying in inaccessible places (wall voids, crawl spaces, etc.), never use bait indoors, and only use bait outside if you are certain that no rodents can get into the house! Baits are not very effective if other food sources remain. Make sure to carefully follow all label instructions on bait products, and use bait stations as required.

For more information on trapping and using poison bait, please visit the UC Integrated Pest Management website.

5. REMOVE HARBORAGE
This must be done as last step; otherwise rodents are driven to other hiding places, often
into your home!
• Thin out dense vegetation
• Eliminate debris and junk piles
• Stack wood neatly and elevate wood-piles off the ground at least 12 inches and stack away from walls or fences

6. MAINTAIN GOOD HABITS
Keep your yard clean and debris-free, always pick up fallen fruits, berries, and nuts and
keep dog droppings picked up and properly disposed of.