Southern Flying Squirrel
(Glaucomys volans Linnaeas)
From: Saunders, D. A. 1988. Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp.
Description: A furred membrane (patagium) extending between the wrists of the front feet and the ankles of the hind feet distinguish both species of flying squirrels inhabiting the Adirondacks. Flying squirrels have small rounded heads, large black eyes, prominent ears, long whiskers, and well-furred tails. Their fur is dense, soft and silky. The tail is horizontally (dorso-ventrally) flattened, the long hairs forming nearly parallel sides and a rounded tip. The general color of the upper portions of the body, head and tail of the southern flying squirrel is drab olive gray, darkest and almost black at the edges of the membranes. The underparts of the body and head are white to creamy white, the hairs showing no gray at the bases (as they do in the northern flying squirrel, G. sabrinus). The tail is white to grayish white below. The southern flying squirrel is smaller than the northern, and is approximately 210-255 mm (8.3-10.0 in) in length which includes an 80-110 mm (3.1-4.3 in) tail. Weight varies from 45-82 g (1.6-2.5 oz).Range and Habitat: The range is from extreme southeastern Ontario and southern Quebec, south through most of the eastern half of the U.S. Small, disjunct populations occur in Mexico and Central America. Although the hypothetical distribution includes the entire Adirondacks, the few records for the southern flying squirrel suggest a distribution limited to the lower elevations, generally less than 300 m (1000 ft) and along the periphery. Deciduous and mixed forests are the primary habitat, but this species occasionally resides in small stands of conifers, especially where mature beech and oaks are nearby.
Each adult builds many nests, abandoning them when they become dirty and flea-ridden. Nests made of shredded bark, leaves, moss, lichens and feathers are usually located in tree cavities, especially abandoned woodpecker holes, but occasionally in buildings and bird houses.
Food and Feeding Behavior: Beechnuts, acorns, hickory nuts, and other large seeds which southern flying squirrels begin storing in late summer in their nests, the ground, and in and around trees form an important part of the winter diet. The seeds of conifers are another source of winter nutrition. Where southern flying squirrels live near bird feeding stations, they also eat sunflower seeds and suet. The inner bark, buds, blossoms, and sap of trees such as the sugar maple are foods taken in the spring. Fruits, fungi, and some species of lichens are other foods. This species is omnivorous and eats substantial quantities of animal foods (more than other tree squirrels and most rodents). These include the flesh of dead animals (carrion), birds eggs, as well as live animals which southern flying squirrels capture, e.g., mice, shrews, invertebrates and nestling birds.
Activity and Movement: Flying squirrels are the most nocturnal and arboreal of the tree squirrels. Although they forage on the ground, flying squirrels spend most of their time in trees, where they climb, walk, or run along branches, hopping over obstacles. The flying squirrels ability to glide from one tree to another is unique among rodents. Before gliding, a flying squirrel bobs and rotates the head, perhaps to gauge the route, and then leaps from a high perch, the feet and cartilaginous spurs extended to stretch the membranes. The airborne rodent sails forward and downward, twisting and turning to avoid branches, the changes in direction aided by a tail which serves as a rudder. Just as it nears the destination, the flying squirrel gives an upward jerk of the tail to land, head upward. Fleshy pads on the feet cushion the shock of impact, and sharp claws clasp the bark. By climbing onto a higher perch, a flying squirrel can glide to a different tree. A single glide usually covers about 10 m (30 ft), but when initiated from a tall tree and oriented downslope, may extend 80 m (270 ft).
Reproduction: There are comparatively few studies of the reproduction of the southern flying squirrel in the wild. These indicate litters present in April and May and again in August and September. It is not known if the same females produces litters during both periods. The gestation period is 40 days. The average litter size is 3 or 4 (extremes, 2-7). Young flying squirrels weigh 3-5 g (0.1-0.2 oz) at birth, and are pink, blind, and without hair except for short whiskers. The eyes open at 28 days; weaning occurs at 35-42 days, and at this age young flying squirrels are fully furred and nearly the same size as an adult. Throughout their development, females may transport their litters to clean nests. The young may stay with their mother until she bears another litter. Some young breed as yearlings, the remainder when 2 years of age. The potential lifespan is 10 years, but few adults survive beyond 5 years.
Predators: Raccoons, foxes, weasels, bobcats, hawks, and owls are some of the predators. House cats often kill flying squirrels, the depredations frequently the first evidence that their owners have of the presence of these secretive tree squirrels.
- Social system - The mating relationships and social pattern of the southern flying squirrel are not well known. The few studies concern populations in deciduous forests. These studies suggest a variable social system with the degree of aggressiveness and territoriality of breeding females. Where nest cavities are abundant, and food trees distributed uniformly, breeding females maintain territories that encompass most of the home range. In other locations, they may defend only the area immediately surrounding the nest. In all areas, a receptive female may associate temporarily with a male, but both occupy separate nests, and males do not aid in the care of the young. Males are less aggressive than females, their home ranges overlap, and sometimes pairs, or trios, may share the same nest. During the winter, up to 19 individuals of both sexes may nest communally, presumably to conserve body heat. Home range size is variable but averages about 0.4 ha (1 acre) for a female, and 0.6 ha (1.5 acre) for a male. Densities vary from 2-12 flying squirrels per ha (0.8-4.8 per acre).
- Communication - Vocalizations are one of the main clues to the presence of this secretive species, and their frequency and variety of cases suggest an important role in regulating social behavior. The vocal repertoire includes many bird-like calls, from “chirps,” “chucks,” and high-pitched, repetitive “tseets,” to sneeze-like sounds. Loud “squeals” and “churs” accompany chasing and mating. The young give ultrasonic and high-pitched squeaks. Individuals emit high frequency sounds during gliding which may serve in echolocation. Females threaten by lunging, and stamping their front feet, which may change to slapping the face of an opponent or to hostile chases. Glands in the facial region may provide substances for marking various features of the home range, for example food stores.
Bendel, P.R. and J.E Gates. 1987. Home range and microhabitat partitioning of the southern flying squirrel (Glaucomys volans). Journal of Mammalogy, 68:243-245.
Dolan, P.G. and D. C. Carter. 1977. Glaucomys volans. Mammalian Species, 78, 6pp.
Linzey, D.W. and A. V. Linzey. 1979. Growth and development of the southern flying squirrel (Glaucomys volans volans). Journal of Mammology, 60:615-620.
Madden, J.R. 1974. Female territoriality in a Suffolk County, Long Island population of Glaucomys volans. Journal of Mammology, 55:647-652.
Muul, I. 1970. Intra-and inter-familial behavior of Glaucomys volans (Rodentia) following parturition. Animal Behavior, 18:20-25.
Sollberger, D.E. 1943. Notes on the breeding habits of the eastern flying squirrel (Glaucomys volans volans). Journal of Mammology, 24:163-173.