Northern Flying Squirrel
The northern flying squirrel is slightly darker and browner than its southern counterpart. The two species’ ecology and habits are similar, although the northern flying squirrel shows a greater affinity for conifers, and the southern flyng squirrel favors nut-producing hardwoods.
The northern flying squirrel inhabits New England as far south as the mountains of northern Pennsylvania; there are also disjunct populations in parts of the Appalachians to the south. Glaucomys sabrinus ranges from the Great Lakes states west to Alaska. Northern flying squirrels inhabit old-growth and mature forests, particularly northern hardwoods (beech, birch, maple) interspersed with hemlock, spruce and fir. Home ranges are estimated at 5 to 19 acres and perhaps larger. Adults do most of their foraging between dusk and midnight, and for one to three hours before dawn.
They feed heavily on lichens and fungi, including many underground ones, truffles and their relatives, which the squirrels sniff out. They also eat seeds, buds, fruits and insects. They den in tree cavities or woodpecker holes during the winter, and in the summer, they may build nests out of leaves and shredded bark, in crotches of conifers high above the ground. Females produce one litter per year, usually with 2 to 4 young. The loss and fragmentation of old-growth forest may be causing a decline in the northern flying squirrel population in Pennsylvania, and it is considered a threatened species here.