Squirrel's belong to the order "Rodentia", with 1650 species, it is the largest group of living mammals. It also comprises forty percent of all present day mammal species.
Tree squirrels of various species may enter buildings and cause damage. The most commonly encountered squirrels include the gray, fox, red and flying squirrel. While they generally build their nests in trees, some species will settle in a rarely used attic space if conditions are favorable.
They can do considerable damage to buildings with their gnawing, and will readily chew on cables and electrical wiring. They may also be very noisy in their activities, will bite if cornered, cause ectoparasite problems to occur in nesting areas and damage garden and ornamental plants.
Tree squirrels are most active in early morning and late afternoon. They feed on nuts, seeds, buds, leaves, bulbs, bark, insects and fruit, and like to store some of these foods in outdoor caches.
The best control method is to prevent these pests from gaining entry into the structure. Sealing any hole larger than a dime, trimming tree branches back 10-feet or more, and ensuring that all attic vents are screened with metal screening material will help to deny entry to squirrels.
Denying food to these animals is also a critical control factor. If bird-feeders are used around the home, it is highly recommended that they be located at least 20-feet away from the home and a conscientious effort made to clean any spilled seed from beneath the feeders on a regular basis.
There are over 365 species of squirrels in seven families. They include the tree squirrel, ground squirrel, and flying squirrel. Plus many squirrel-like mammals such as the gopher, ground hog and prairie dog.