They can be cute, but all squirrels are rodents. They cause damage and carry diseases. Custom Pest Solutions has experience in humanely removing these pests.
In the suburbs, there may be 10-20 gray squirrels in a 1 acre area, depending on the food supply (e.g. bird feeders), and housing situation (e.g. hollow trees, open sheds, and attics). Gray squirrels have at least 2 litters per year. The first in March-April and the second around July-August. Litters can contain anywhere from 1 to 6 young, with 2 to 4 being most common.
All squirrels mainly eat nuts, fruits, berries, and seeds. Gray squirrels have been known to eat baby nesting birds as well. The only other squirrel that is carnivorous is the flying Squirrel, which is rarely seen because it is nocturnal.
All rodents gnaw. Gray squirrels cause damage just by their chewing. They will chew into attics, and, once inside, can do extensive damage to wiring. They can fall into chimneys and end up in your fireplace, or, if the damper is open, they may end up running around your house. Occasionally, they will nest in a garage as well. Normally, you will hear gray squirrels inside the attic, or running in the soffits in the early morning and, again, later in the day (from 4PM till dark). They are generally quiet at night. Gray squirrels prefer to enter your house from a tree that is close enough to gain access to the roof, but sometimes they will climb a deck or a porch to gain entry to the house, or cross a utility wire.
All squirrels have to leave a building in order to find food. You can wait until they leave, and then close up the holes. The problems with this method is that between March-May, and July-October, you may trap the young ones inside causing them to die. Bad odors, flies, etc. will be the result. Another problem is that sometimes they will just chew in somewhere else. Animals causing the problem should always be removed, and then the holes sealed up to prevent others from infesting the structure.