Tree squirrels nest above ground, in cavities in tree trunks or in aerial nests they construct. Their diet is primarily nuts, seeds, berries, fruit, and flowers and flower buds. They may also feed on tender bark, and occasionally on insects, bird eggs or young birds, mice or other small animals. Tree squirrels are diurnal, or active in the daytime. They may live as long as 12 years, but between 4 and 7 years is more normal in nature. They have one to two litters per year, usually in very early spring or late winter, with 3 to 6 young per litter. They do not hibernate, but their activity may diminish a great deal in the winter months. Around structures they can be destructive to wires or other utilities that enter the structure, and commonly find their way inside attics where they cause great damage to wires and other materials inside. It also is common for them to fall into vents or chimneys on the roof, or possibly find their way into wall voids, where they may die and cause odor and pest problems. They may enter through openings only 1.5 inches wide.
In general, tree squirrels are protected animals, and it is illegal to kill them without specific permission from a wildlife agency. If tree squirrels are found to be causing serious damage permission may be given to trap and relocate them, or to kill them if necessary. Exclusion from a building is the most important control measure for these animals, and removal by live-trapping the best alternative if they have entered.