Males have slightly larger ranges than females, due to an increase in their range during the breeding season. Home range sizes also increase during spring and summer for both sexes and are negatively correlated with food supply and squirrel population density. Eastern grey squirrels are most commonly found in mature continuous woodlands greater than 40 hectares in size. Densities are highest in habitats composed of tree species that produce foods suitable for storing over winter such as oak, hickory and walnut. Due to a variability in seed production in different years, a diversity of nut trees is important to support high densities.
Grey squirrels are generalist feeders.
Squirrels feed heavily on nuts, flowers, and buds of 24 oak species, and 10 species of walnut, hickory and pecan. Other food items include the fruits, seeds, buds or flowers of maples, mulberry, hackberry, elms, buckeyes, horse chestnuts, wild cherries, dogwoods, hawthorne, hazelnut and ginkgo. Pine tree seeds and pollen cones are readily eaten including cedar, hemlock, pines, and spruce. Fungi are also consumed when readily available in summer, as are cultivated crops in winter. Animal food items include bones, bird eggs, nestlings, and frogs.