Northern Flying Squirrel

Description: Varying according to the subspecies and season, its upper parts range in colour from cinnamon to pecan brown, while its underparts are white or creamy white and often washed with some shade of buff or yellowish. Its tail varies from cinnamon to dark grey or even blackish above, usually darkest near tip, and below varies from pinkish-cinnamon to nearly black.

The sides of its head (and sometimes its face) are grey, often with wash of buff or dark grey. Its tail is densely furred and flattened, with a rounded tip. It is larger and more robust than the Southern Flying Squirrel, and the hairs on its abdomen are greyish-white at the tips and lead-grey at the base, rather than white at the base.

Distribution: Found throughout much of northern North America in woodland typically dominated by conifers, or a mixture of conifers and deciduous forest, and occasionally broad-leaved deciduous forest. In the southern Appalachian Mountains it is found between 1000–1800 metres in forests of spruce (Picea sp.), fir (Abies sp.) and mixed hemlock (Tsuga sp.) and adjacent mature hardwoods.

In Pennsylvania it occurs in forests of beech (Fagus sp.), Yellow Birch (Betula alleghaniensis) and Sugar Maple (Acer saccharum). In south-eastern New York, optimal habitat contains Beech, Sugar Maple and Red Oak (Quercus rubra), various birches, other deciduous trees and some hemlock and White Pine (Pinus strobus).

Reproduction: The female produces one litter a year, although under ideal conditions some females will produce a second litter. Mating usually takes place in late March and early April with the young born between May and June, although young have been found in July and even December. The gestation period appears to be between 37–42 days and litters usually consist of two to four young, but may contain up to six.

Diet: Acorns, lichens, hazelnuts, beechnuts, other nuts, conifer and hardwood seeds, buds, staminate cones, catkins, wild fruits, insects, fungi, tree sap, with some records of eating roosting birds and eggs. Truffles appear to be a major food item in at least some regions and include at least 26 genera.

Ecology: Nocturnal, it usually nests in hollows in large trees. Nests are typically about 30 centimetres in diameter and encased in twigs, bark and roots, with one or two entrances and used by females and their young. It builds several smaller outside nests, about 18 centimetres in diameter, on platforms of sticks or on top of abandoned bird nests, and lines them with finely shredded bark, moss, lichens, feathers, grass, pine needles, leaves, fur and other material.

Its home range is typically 0.8–4.9 hectares with densities ranging from 0.3–10 animals per hectare. It is most active at dusk and at dawn, although on very cold nights it may have a single activity period in the middle of the night.

No activity has been observed when temperatures are below —20°C. Major predators are the Spotted Owl (Strix occidentalis), Long-tailed Weasel (Mustela frenata), Ermine (Mustela erminea), American Marten (Martes americana) and Bobcat (Lynx rufus).

Status: Least Concern.