These are preferred home sites, especially for winter and for nurseries, because they provide good protection from weather and enemies. Leaf nests are usually built in the tops of large trees and consist of a rough twig framework with a bulky pile of leaves heaped layer upon layer. The squirrel hollows out a nest cavity in the center of the leaves. In any patch of woods or forest, squirrels live in loose colonies. All the members of one colony recognize each other and are familiar with all the nest sites and food sources in the area.
Gray squirrels are early risers and leave their nests with the first light of day.
They are most active about sunrise and shortly thereafter, and again in late afternoon. Most of the day they stay in their nest or lie on a limb or other platform where they sleep and sun themselves. By comparison, fox squirrels come out later and retire earlier and are frequently more active in the middle of the day. Gray squirrels are more wary than fox squirrels and thus are regarded by most sportsmen as harder to hunt. The importance of acorn and nut crops is shown by the drastic fluctuations in squirrel numbers following years of good or bad mast production.