The grey squirrel, scientifically known as Sciurus carolinensis, is a common and captivating member of the rodent family, Sciuridae, that thrives across eastern North America. Understanding the intricacies of the Grey Squirrel Family – their habitat, diet, social behaviors, and life cycle – offers a fascinating glimpse into the natural world right in our backyards and parks.
Habitat and Geographical Range of Grey Squirrels
Grey squirrels are most at home in the lush deciduous forests of eastern North America. Their range extends into southern Canada, where these forests transition into mixed woodlands. Within the Adirondack region, grey squirrels flourish particularly in areas like the Champlain Valley and around Lake George. These locations boast a rich supply of oak trees, a crucial food source for them.
While primarily found in old-growth hardwood forests, grey squirrels also adapt to mixed hardwood-coniferous forests in the Adirondacks, reaching elevations up to 915 meters (3000 feet). Their abundance varies, from rare sightings in deep forests to common occurrences in urban settings such as towns, cities, and parks. Notably, residential bird feeding stations play a significant role in supporting grey squirrel populations, especially in areas like Blue Mountain Lake where they might otherwise struggle to thrive.
Historically, observations noted the scarcity of grey squirrels in the central Adirondacks. Early accounts even documented individual sightings by hunters, highlighting their unusual presence in these areas. These sightings were often attributed to sporadic migrations. Before extensive deforestation, grey squirrels were known for large-scale migrations, possibly triggered by population surges following plentiful mast crops or the failure of these crops. Historical records, such as the 1749 invasion of Pennsylvania by grey squirrels (resulting in bounties for over 640,000 squirrels), illustrate the scale of these events and the substantial size of grey squirrel populations at the time.
While once considered rare residents in the central Adirondacks, by the mid-1930s, increased sightings, like those reported by Chief Ranger Oja in Huntington Wildlife Forest, suggested a change. It’s speculated that logging activities in the Adirondacks may have facilitated the expansion of their range.
For shelter, a grey squirrel family utilizes either a leafy nest, a spherical structure of twigs and leaves lined with shredded bark and leaves, or, preferably, a cozy tree cavity.
Diet and Feeding Habits of the Grey Squirrel Family
The grey squirrel family’s diet is primarily composed of seeds and nuts. Acorns, beechnuts, butternuts, and hickory nuts are staples, especially during autumn and winter, providing essential energy for colder months. Beech and nuts are particularly important in the Adirondacks due to their local abundance. Smaller seeds from maples, ashes, and basswood are also consumed, though to a lesser extent. Buds, flowers, and the inner bark of these trees and others supplement their diet in late winter and spring, offering variety and necessary nutrients as winter stores dwindle.
During summer, grey squirrels broaden their food intake to include fungi, berries, and fruits. Black cherries are a particular favorite during this season. In southern regions, a grey squirrel needs about 2 pounds of food weekly; however, Adirondack populations likely require more to cope with harsher climates and energy demands.
A characteristic behavior of the grey squirrel family in autumn is their method of harvesting and storing food. They clip nuts directly from tree canopies and scatter hoard them by burying them in the ground. Their acute sense of smell is crucial for retrieving these buried caches, even under a foot or more of snow. This scatter hoarding behavior plays an ecological role, as overlooked nuts can sprout, contributing to forest regeneration. Tree cavities may also serve as secure storage locations. This efficient food storage strategy is vital for the survival of grey squirrels in regions like the Adirondacks, where heavy snowfall is typical.
Activity Patterns and Movement
Grey squirrels are diurnal animals, meaning they are most active during the day. However, during periods of severe winter cold, the grey squirrel family may retreat to their dens or nests for several consecutive days. They emerge primarily at midday to access their stored nuts. On typical days, their peak activity times are the 2-3 hours after dawn and again before dusk. The rest of the day is often spent resting in their nests or basking on tree limbs. Overcast skies or courtship periods can extend their activity throughout the day.
Known for their agility, grey squirrels are truly arboreal acrobats. They exhibit remarkable skill in climbing, running, and leaping through trees. Their sharp claws provide excellent grip on bark, while their long tails act as balancers during leaps and turns as they navigate branches, even on slender, pencil-thin ones. When sensing danger, a grey squirrel will freeze, pressing its body and tail flat against a tree trunk or limb on the side opposite the perceived threat, cleverly inching around to remain hidden from intruders.
Equally adept on the ground, they move with ease by walking, hopping, bounding, and running. Their tails stream behind them as they achieve speeds of 10-15 mph, combining running with powerful leaps. Despite not being aquatic animals, grey squirrels are capable swimmers. They readily enter water and can swim considerable distances, even several miles, as documented by observations of grey squirrels crossing lakes in the Fulton Chain.
Reproduction and Life Cycle of the Grey Squirrel Family
Courtship in the grey squirrel family is a lively affair, similar to that of red squirrels. It involves “mating chases” where one to ten or more males pursue a female in estrous. Typically, the dominant male will mate with the female, although this is not always the case. Grey squirrels have two main breeding periods annually: one in late winter and another in mid-summer. This results in litters being born in March-April and again in July-August. Adult females, two years or older, can produce one or two litters each year, while younger, yearling females usually have just one litter.
Following a gestation period of 40-44 days, the female gives birth to a litter ranging from 1 to 9 young, with an average of 2 or 3. The newborns, called neonates, are born hairless and blind, weighing only about 14-15 grams (0.5 oz). Their eyes open at 28-35 days old, and they develop a full coat of fur by the time they begin to venture out of the nest or tree cavity, around 42-49 days after birth. Weaning occurs relatively late, between 56-70 days of age, after which the young squirrels start to disperse. Offspring from the late summer litters may stay with their mother throughout the winter months. Grey squirrels reach sexual maturity in the spring or summer following their birth. The average life expectancy at birth for a grey squirrel is 1-2 years, but adults that survive to adulthood typically live around 6 years. The maximum recorded lifespan is 12 years in the wild and an impressive 20 years in captivity.
Predators of Grey Squirrels
Grey squirrels are preyed upon by a variety of predators common to small to medium-sized mammals, highlighting their role in the food chain.
Social Structure and Communication within the Grey Squirrel Family
Grey squirrels, while often seen individually, have a defined social system. Relationships among grey squirrels living in proximity are structured by hierarchies. Older, larger adult males are dominant over smaller males. Females are generally subordinate to males, except when they have litters. During this maternal period, females become territorial, defending small areas around their dens or nests. The home ranges of both males and females overlap, with males typically having larger ranges. Home range size is primarily influenced by food availability, usually spanning 0.4-2.4 hectares (1-6 acres). Adult grey squirrels are promiscuous and do not form lasting pair bonds. The only stable social unit is the association between a female and her young, which can sometimes extend into the winter.
Communication within the grey squirrel family is rich and varied. They heavily rely on vocal signals, producing a wide array of vocalizations. Before and after mating, females emit sounds described as “kuks,” “quas,” and “moans.” Young squirrels produce a “shrill-cry” when disturbed, signaling distress. Alarmed adult grey squirrels “buzz” and use slow “kuks,” low “moans,” and high-intensity, repetitive “quaas” to communicate danger or agitation. These vocalizations may be accompanied by foot-stamping and tail-waving, enhancing the signal. Visual communication is also important, involving postures and motor patterns where tail position, movement, and shape are crucial components. Anal glands provide scent cues that convey sexual status and potentially other information, adding another layer to their complex communication system.
Further Reading:
- Barkalow, F.S. and M. Shorten. 1973. The world of the gray squirrel. J.B. Lippencott Co., Philadelphia. 160pp.
- Barkalow, F.S. and R.F. Soots, Jr. 1975. Life span and reproductive longevity of the gray squirrel, Sciurus c. carolinensis. Journal of mammalogy, 56:522-24.
- Horwich, R.H. 1972. The ontogeny of social behavior in the gray squirrel (Sciurus carolinensis). Verlag Paul Pary, Berlin, Hamburg. 103pp.
- Johnson, C.E. 1937. Part I. Preliminary reconnaissance of the land vertebrates of the Archer and Anna Huntington Wildlife Forest Station. Roosevelt Wildlife Bulletin, (4):552-672.
- Uhlig, H.G. 1956. The gray squirrel in West Virginia. Bulletin No. 3. Charleston, West Virginia Conservation Commission.
