When den trees are scarce, leaf nests are used year-round. Food habits of fox squirrels depend largely on geographic location. In general, fox squirrel foods include mast, tree buds, insects, tubers, bulbs, roots, bird eggs, seeds of pines and spring-fruiting trees, and fungi. Agricultural crops such as corn, soybeans, oats, wheat, and fruit are also eaten. The range of fox squirrels in the the eastern states has been greatly reduced in the past 100 years.
Habitat reduction is one cause.
The Coastal Plain of North Carolina and other southern states is undergoing rapid deforestation and forest modification due to accelerated residential and agricultural development, and intensive management techniques in commercial forests. One of the primary reasons for the decline of the endangered Delmarva fox squirrel is timber harvest. As large trees are removed so are much of the areas that provide the Delmarva fox squirrel with an open understory habitat. Logging practices that include harvesting all the big hardwoods and replacing them with stands of pure loblolly pine are also detrimental to Delmarva fox squirrels, since stands of pure species do not provide good fox squirrel habitat.