Chipmunks, Squirrels: Cute Rodents, Ugly Pests
You wouldn’t ordinarily think of those cute little chipmunks
frolicking in the sun outside your home as rodents, but they are
pests that can invade your home during the winter months and make a big
Besides chipmunks, four-legged pests that sneak indoors for a snug winter
home include mice, rats, squirrels and even raccoons
and opossums. What’s most worrisome is that rodents spread diseases
such as hantavirus, a potentially deadly lung disease.
While there are measures homeowners can take to eliminate rodents, the smart
advice of experts is to call a local pest management professional to
identify the problem, survey for, and control the rodents using an
Integrated Pest Management (IPM) approach.
“Knowing when to call an expert is important,” says Mark Lacey, director of
technical and field services for the National Pest Management Association (NPMA),
a trade organization representing professional pest management firms in the
U.S. and around the world.
“Searching out the hiding places of rodents and other pests and precise
targeting of management efforts requires a competent, knowledgeable and
technically trained specialist, a pest management professional who has the
special training, experience and tools necessary to assure adequate
protection against destructive pests, ” he advises.
Rodent season starts in October, when mice, rats and
raccoons search for warmth, food and safe hiding places, says Richard
Poche, owner of Genesis Laboratory in Fort Collins, Colorado, which has
specialized in pest management research for the past 30 years.
The safe havens, he says, “may be under your refrigerator, in your garage,
or in the attic,” estimating that 21 million homes in the U.S. are invaded
by rodents each year during the peak season from October through February.
Take the cute little chipmunk. While they don’t hibernate all winter in most
areas, they will become inactive for part of the winter. They assemble a
collection of winter food and store it in their burrows, which, depending on
the species, may be in stone walls, fences, under bushes or in turf.
Chipmunks go into open areas such as garages in search of food such as grass
seed, bird food and pet food. As with other rodents such as mice, chipmunks
can make quite a mess of a bag of seeds. These rodents can be kept outside
by sealing doors or plugging foundation holes with materials such as copper
mesh, which can be supplied by a pest control firm.
Squirrels are another bothersome rodent. They often come into homes in the
fall and build nests in attics, behind soffit panels, or in high wall voids.
Gray squirrels are active in the daytime and flying squirrels are active at
Squirrels can do a lot of physical damage to a structure by gnawing holes,
chewing wires and contaminating and staining surfaces with their urine and
droppings. They may bring fleas, mites and lice into homes. The pine cones
they store can attract and support a wide range of secondary pests, such as
beetles, moths or mites.
At least two species of tree squirrels have been associated with human
diseases, and gray squirrels sometimes become aggressive and bite humans.
The best long-term control is removal, which is usually executed by covering
all entrances of the home with heavy sheet metal or hardware cloth, followed
How do you know you have rodents? “You can hear scampering or gnawing sounds
late at night in the attic or behind the walls,” says Noor Tietze, vector
ecologist with the Santa Clara County (Calif.) Mosquito and Vector Control
You may also find rodent droppings in undisturbed areas of the home such as
pantries, attics, garages, under baseboards, and along walls, or see
telltale signs of gnawing on packaged goods, cardboard boxes and walls near
pipes and vents. And if you find your dog or cat pawing excitedly at a
kitchen cabinet or the base of your refrigerator or stove, you can assume
there is some pesky little critter hiding there.
Once inside, rodents can be extremely destructive. They chew through wall
boards and can eat through cardboard boxes, wood and plaster. Rodents also
gnaw on electrical wiring that could potentially cause an electrical fire.
More than one-fifth of the “fires of unknown origin” in the U.S. are
probably caused by rodents’ gnawing matches or wiring.
Rodents also carry diseases and fleas and leave waste. According to the
Atlanta-based U.S. Centers for Disease Control, a potentially deadly
respiratory disease is caused by hantavirus, which is carried by rodents,
primarily mice. Hantavirus is contracted primarily by inhaling airborne
particles from rodent droppings, urine or saliva left by infected rodents or
through direct contact with infected rodents.
Although relatively rare, hantavirus is known to kill up to half the people
who get it. After suffering from what first seem like flu-like symptoms,
victims usually die quickly with severe lung damage.
To help prevent problems with rodents you should:
- Clean up thoroughly and often any spilled food, garbage, pet food or
grain that might attract rodents. Don’t forget decorations hung on doors
or walls, and don’t leave food out in a pet’s dish overnight.
- Keep all garbage in tightly-closed metal cans, and keep the cans are
area around them clean as well. Clean up and remove all trash and rubbish,
especially near your buildings.
- Be sure all outside doors, windows and vents fit snugly, with no gaps,
and are kept closed, especially at night. A mouse needs only a 3/8-inch
crack or hole to get inside.
- Seal up any hole or crack on the outside of any building that is big
enough for a rodent to enter. Pay special attention to places where wires,
pipes, or other utility lines enter a building.
- Keep plants and shrubs trimmed back at least 12 inches from the outer
surface of any building. These can provide rodents with food, shelter, and
an easy way up to higher entry points. Rodents are expert climbers.
- In urban settings, trim back or remove any extensive plantings of
low-growing shrubs, especially Taxus or Junipers.
A professional pest management firm is qualified to inspect your home for
the presence of pests. Their technicians can provide homeowners with
immediate information and assistance in controlling them. They’ll also offer
advice on preventive measures to avoid similar pest problems in the future.
For more information about rodents or to locate a pest management
professional, please visit
www.pestworld.org or contact Cindy Mannes at 703-573-8330 or