Pest Identification And Information

Squirrels

GENERAL INFORMATION

• Squirrels are members of the rodent family.
• Gray and Red squirrels are the most common in Minnesota, with the Gray being more numerous.  The Fox and the Flying squirrel can sometimes be a problem.  This fact sheet will deal mostly with the Gray Squirrel.
• Squirrels prefer forested or treed areas: Gray and Fox inhabit both hardwood and coniferous areas, whereas the Red squirrel prefers coniferous but will also occur in mixed forested areas.
• Squirrels (other than Flying) are diurnal, meaning that they are active during the day, however if trapped within a wall void they will make noise until they die or escape.
• Gray squirrels may sometimes be totally black or white.

BIOLOGY

Gray Squirrels breed at about 1 year of age.  They can breed throughout the year but usually late December/early January and again in June.  Breeding in the cold northern areas is usually done during the warm weather months.  Young squirrels may breed only once in their first year.  Their gestation period is about 40 - 45 days.

About three young comprise a litter.  They are born hairless, blind and their ears are closed.  The young begin to explore outside around the time they are weaned, which is about 10 - 12 weeks.  At weaning they are about half of their adult weight, which is about one pound for the Gray squirrel, two thirds of a pound for the Red squirrel.

FEEDING

Squirrels prefer to eat at dusk. They will eat a great variety of foods and will adapt quickly to unusual food sources.  Typically, they will feed on:

• Acorns
• Walnuts
• Other Nuts
• Berries/Fruits
• Bulbs
• Fungus
• Bird Eggs
• Small Birds
• Small Mammals
• Dog Food
• Insects
• Corn 

During peak population periods, when food is scarce, squirrels may chew bark from a variety of trees. Red squirrels may eat pinecones and buds.

DAMAGE

In residential areas squirrels sometime travel along power lines and will short out transformers. They gnaw on wires, enter buildings and build nests in attics. They can occasionally damage lawns by burying or searching for and digging up nuts. They can chew bark and clip twigs of many ornamental trees or shrubbery planted in yards. Many times squirrels will rob bird feeders of birdseeds and in some cases chew to enlarge the openings of birdhouses in order to enter and eat nestling songbirds.

In gardens squirrels may eat planted seeds, mature fruits, or grains such as corn.

CONTROL

There really isn’t any control measures for squirrels other than trapping, however there are some preventative measures which can help to prevent squirrels from entering structures.

• Trim tree branches and limbs to about 6-8 feet away from the structure to prevent squirrels from jumping on the roof.
• Inspect all roof overhangs, soffits, fascia boards etc. make sure they do not have any cracks or holes and that they are tightly attached to the framing.
• All roof vents should be inspected to make sure they are properly screened, not loose and in good repair.
• Keep bird feeders away from the building, perhaps using a “squirrel proof” type of feeder.

Trapping

• Most squirrels can be caught from the outside, close to the entrances to their nesting area.
• You can easily place the traps on the underside of overhangs, soffits etc. by putting some nails or hooks into the wood soffit or fascia boards. That way you can get the trap as close as possible to the opening.
• If you trap on the inside of the attic, place the traps on some boards, if placed on the loose insulation, the trap pan may not work properly.
• When placing a trap on the roof, make sure it is facing up or sideways, as squirrels do not like to crawl down into a trap.
• The best bait to use: cut an apple in half, spoon out a depression, fill the depression with peanut butter, stick nuts into the peanut butter. Three things are attracting the squirrel, the moisture from the apple, and the smell of the peanut butter and the sight of the nuts. You can also use peanut butter and bread.
• Do not contaminate the trap with chemical, soap, odors or the scent of other animals from previous trappings. You should wash the trap after each use, use clear water, no soap or bleach.
• After trapping place paper towels or crumpled newspaper into entrance holes, if it is not moved or disturbed the next day, the hole can be sealed, as there are no more squirrels using that entrance.
• After trapping we recommend you relocate it at least 10 miles away in a non-residential area.
• Optionally one may use large rat snap traps or large glue boards, being mindful this isn't the most environmentally friendly approach.