It's fairly common knowledge that squirrels will nest in attics, causing damage and disturbing the human residence of the home. But what many people do question is: How do squirrels get into the attic?  Why are squirrels attracted to attics? And … How do you get rid of them?

To see just how well squirrels can jump, check out the slow-motion jumping squirrel video by Pesttools Technical Director Bill Earl.

But squirrels can also run, climb, and gnaw their way into your attic. Following are Squirrel Facts, adapted with permission from "How to Evict Squirrels" by Bill Earl.

Squirrels Are Powerful – and Destructive

• Squirrels have been known to climb the brick or stucco wall of a four-story apartment house in seconds.
• To deal with obstacles in its path, a squirrel can pull apart terra cotta and slate roofs. It squirrel can chew straight through good quality shingles and sturdy wood to gain access to your house.
• With the biting power of 7,500 pounds per square inch, a squirrel can chew through aluminum fascia capping and louvered aluminum gable vents.
• Even brick is not impenetrable. They have been seen to climb down the outside of a chimney and push in a brick to enter an attic crawl space.
• A squirrel will chew a hole in high, hard-to-reach parts of the roof.

Why do squirrels live in attics?

• Attics are warm, dry, friendly places where a family of squirrels can settle down and build a nest, store food, and use the bathroom in relative safety and comfort from the dangers of the natural world.  

• But their most important reason for being there is to have babies.
• In the spring and fall, the squirrels that are heard running around in the early dawn hours are most likely the young.

Squirrels are very territorial.

• Once squirrels take up residence in your attic, they stake it off as their territory. In large attics, one end is will become nesting area and the opposite end the latrine. That unmistakable odor of urine that is imbedded in your attic marks their territory.
• The life span of the Eastern Grey Squirrel ranges from three and eight years. In houses with infestations spanning decades, generations of squirrels may have been born in a single house.
• A squirrel mates in early winter and produce offspring by late spring. The average litter consists of four squirrels. A second litter in midsummer is not uncommon. Usually, there is a food stash of nuts stored in the walls, attracting many more squirrels to your house than you might have previously imagined.

Battling squirrel problems is like fighting a miniature army:

• A squirrel may work alone or with others in groups. Several squirrels will work in shifts, day and night.
• The aggravating sound you hear at 1:30 in the morning is the squirrels chewing a hole from the inside of the attic to the outside.
• The reason you don't actually see the squirrels chewing on your home is because, according to Professor James Hare of the University of Manitoba, squirrels warn each other of impending danger, in an ultrasonic voice above our hearing range.

What can you do about squirrels in the attic?

1. With any squirrel problem, you should first do the things that help your situation. First, remove any bird feeders, secure the garbage cans, and cut the tree limbs back around the house so squirrels do not have easy access to the roof.
2. Then, you need to make the attic unattractive to them. As explained by Earl, "Squirrels see your attic as a nice place to live and they want to be there. A nasty environment must be created, an environment so nasty that they will be repelled and not want to be there."
   One option is the Evictor Strobe Light invented by Earl because he was having problems with squirrels in his attic. As he describes it, "I had squirrels in my own attic crawl space for 25 years. I was anxious to solve my own problem. I installed 3 Evictor Strobe Lights in my own attic and I have been squirrel free ever since! Sometimes it seems like a minor miracle not to hear them running, jumping, and chewing in the middle of the night."
3. Finally, wait about a month after the squirrels are gone, then seal the entrance/exit holes to keep squirrels and other pests from getting back in.
4. If squirrels are in the living areas of your house, check out Humane Society recommendations at Squirrels in Your House and How to Get Them Out.