Your Land & Water September 2026
THE WORLD OF EASTERN SQUIRRELS
We are all familiar with squirrels and find them either charming or annoying, and sometimes both, especially as they gobble up all the bird seed we put out. But most of us don’t really know that much about these energetic little mammals.
There are over 200 species of squirrels around the world. They belong to the family Sciuridae and can be divided into three groups: tree squirrels, ground squirrels, and flying squirrels. The Sciuridae family demonstrates incredible adaptability, with species thriving in tropical rainforests, temperate woodlands, arid grasslands, and even urban environments. Squirrels are found on every continent except Australia and Antarctica.
NEW JERSEY SQUIRRELS
In New Jersey, the primary tree squirrel is the Eastern Gray Squirrel (Sciuris carolinensis) that we know from the deciduous trees in parks and our backyard (and bird feeders). The smaller American Red Squirrel (Tamiasciurus hudsonicus) can also be found here but is predominantly a resident of coniferous woods. They are more numerous in northern forests
but are known to live in the NJ Pinelands.
A variety of species of ground squirrels are found in the western U.S. but, in the East, the Eastern Chipmunk (Tamias striatus) is our only ground dweller. They prefer forest edges, clearings, and areas with fallen logs or rock piles that offer both food sources and cover.
In the eastern half of the country, the Southern Flying Squirrel (Glaucomys volans) is native, found in deciduous and mixed woods from southeastern Canada to Florida. They are much smaller than the Eastern Gray Squirrel by 8 to 10 inches, counting the tail. They are nocturnal and secretive, so are difficult to see. They do not actually fly but, rather, glide from one tree to another, using the large skin between their claws called a patagium.
DIET AND FEEDING BEHAVIOR
The diet of all three groups is similar. They feed on nuts, seeds, fruits, berries, leaves and stems, fungi and mushrooms, insects and larvae, and occasionally on birds’ eggs and mice. Diet varies by season according to what is available.
Squirrels store food for the winter, since they do not migrate or hibernate, although chipmunks do enter states of torpor - a period of reduced physiological activity characterized by lowered body temperature, heart rate, and breathing. Unlike true hibernators, such as groundhogs, chipmunks wake up periodically throughout the winter to feed. These cycles typically last several days, during which their metabolic rate plummets. Once their stored energy reserves deplete, they awaken, consume some of their stored food, and then return to torpor.
FOOD STORAGE
Squirrels are highly intelligent. Gray and flying squirrels utilize hundreds or thousands of stored nuts which have been cached for months. They generate these sites by burying nuts 2 to 5 inches deep in loose soil in numerous locations, called scatter caching. They both excel in spatial memory, especially gray squirrels, remembering the location of their caches and able to relocate about 75% of buried items. Sites are marked with scent for later identification, but they also use spatial landmarks such as rocks and trees and triangulation to create mental maps from numerous reference points. They seem to remember approximate burial dates, as well, which enables them to prioritize the retrievals. Finally, we know they are super problem-solvers. Their behavior at bird feeders makes this obvious.
Red squirrels feed more on the seeds from pinecones and form one or more centralized “middens” to store their supplies. These middens consist of large piles of cones, cone scales, and debris that serve as both food storage sites and territorial markers and are placed near nest sites and water sources. They can be several feet high, decades old, and can be passed down between generations.
Chipmunks are also intelligent, but their expertise is more specialized — they are highly efficient at ground-based foraging, caching, and burrowing. All squirrels use internal cheek pouches to carry and store food, but chipmunks can seem to stuff in more than the others. Their caching is different from gray, red, and flying squirrels, however. They create extensive larder hoards within their burrow systems, capable of storing 8 pounds or more of food for winter consumption.
PHYSICAL CHARACTERISTICS
The Sciuridae family of rodents share certain physical features: sharp incisors for gnawing, strong hind legs for jumping, and a highly flexible skeletal structure that aids climbing and gliding. Squirrels can turn their ankles about 180 degrees, allowing their wrists to support their body weight while climbing in any direction, including headfirst down a tree. Animals that cannot turn their ankles like this, such as cats, may be able to easily climb up trees but have a much harder time climbing down.
Gray squirrels use their tails to aid their superb balance, acting as a balance pole during acrobatic leaps, as a parachute during falls, and as a communication device during social interactions. Whenever you see a squirrel standing still twitching its tail, it is usually sending some type of message such as warning other squirrels of danger or to stay away from its food caches.
COMMUNICATION
Chipmunks, and gray squirrels especially, also have a wide variety of vocalizations. Chipmunks use a “chip” note to warn of aerial threats and a “chuck” call for ground dangers. Gray squirrels have three different alarm calls – a sharp bark alert for ground predators, a series of kuk-calls warning of aerial threats, and longer, more complex quaa-calls indicating specific danger types. They also make two different social sounds including soft muk-muk calls between family members, and teeth chattering warnings in territorial disputes. You are unlikely to hear it, but they purr, making contentment sounds during grooming and feeding.
Both our native tree squirrels and chipmunks maintain complex territorial systems and, except for mating, are largely solitary in their foraging and daily life. Flying squirrels are much more social and have been observed flying and foraging together in large groups. In addition, they often cluster together in dens as it gets colder, to conserve energy. However, in the summer months, they tend to forage and cache alone in their home range. In all three groups, family members may stay together more, or longer, although usually without males.
MATING & NESTING
Gray and red squirrels, chipmunks, and flying squirrels have similar mating and breeding characteristics. In our southern New Jersey locale, there are usually two breeding seasons annually, although timing varies between the three types and is influenced by environmental conditions and food availability. The primary breeding season for gray squirrels runs from December to February, while for flying squirrels and chipmunks it occurs from March to April. The second breeding season for gray squirrels is typically during May to July. Flying squirrels and Chipmunks run slightly later, from early to mid-summer for flying squirrels and late summer to early fall for chipmunks. This second period is affected by whether trees are “masting” - producing large crops of nuts and seeds in some years and not in others.
Mating occurs through a complex courtship ritual involving chase sequences, vocalizations, and scent marking. Males establish temporary territories around potential mates, defending them against competitors through aggressive displays and physical confrontation. Successful males may mate with multiple females during the breeding season and females will mate with more than one male.
The favored nest chambers for the blind and helpless offspring of tree squirrels are cavities and woodpecker holes, although leafy ball nests made of woven twigs, leaves, and soft materials may be used in summer. These latter nests, which are easy to see in the fall after leaf drop, are used as refuges and resting sites in summer, while cavities are used more for breeding and in winter. Gray squirrels become independent at about 12 weeks and flying squirrels at 17 weeks.
Chipmunk nesting differs radically. They excavate elaborate, often very long, burrows underground, with multiple entrances and separate chambers for nesting and for food storage. These can be as much as 20-30 feet in length, with construction requiring weeks of excavation, and the chipmunk moving tons of soil, grain by grain, in its cheek pouches. Chipmunk offspring are raised in the burrow and leave this protective nest at
6 to 8 weeks.
These three small mammal groups act as seed dispersers, soil aerators, and even indicators of forest vitality. Their foraging and caching behaviors help propagate plants, because they forget a significant percentage of the cached locations. Additionally, some seeds survive digestion and are dispersed after traveling through squirrel digestive tracts. Other seeds with hard outer shells are helped by being gnawed by squirrels, which creates small cracks that allow water to enter to trigger the germination process.
Squirrel food selection helps to disperse fungi spores and the output of hardwoods (e.g. oak, hickory) which rely on carriers such as squirrels and birds to disperse their seeds. Squirrel habits of burying caches in loose soils near the soil surface and in nutrient-rich microsites, such as beneath leaf litter or near decaying wood, provides young seedlings with conditions they need to thrive.
Ground squirrels aerate the soil with their burrows, while flying squirrels connect fragmented forests through their gliding, maintaining ecological continuity as they move tree nuts and seeds to new sites. The territories of squirrels can be extensive, which enables long-distance dispersal and helps maintain and expand forest ecosystems. Tree-to-tree transport by squirrels is particularly important in fragmented forests or areas where natural seed dispersal mechanisms are limited. By moving seeds across gaps, squirrels help maintain genetic diversity within tree populations, which is crucial for the long-term health and resilience of forest ecosystems.
Article by Suzanne McCarthy
SOURCES:
American Red Squirrel: Complete Species Guide. How To Help Animals.
Connecticut Department of Environmental Protection. Flying Squirrel Factsheet. https://portal.ct.gov/deep/wildlife/fact-sheets/flying-squirrel?archived=true
Flying squirrel. Wikipedia. https://en.wikipedia.org/wiki/Flying_squirrel
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How To Help Animals. Chipmunks. https://howtohelpanimals.com/mammals/squirrels/eastern-chipmunk-complete-species-guide/
How To Help Animals. Eastern Gray Squirrel: Complete Species Guide. https://howtohelpanimals.com/
JeannetteZ, Interesting Facts About Squirrels. (2025, July 5) Close to Nature. https://close-to-nature.org/interesting-facts-about-squirrels/
John, Brian. 40 Types of Squirrels: Species Identification with Pictures. (Last updated on 04/18/2026) https://enjoythewild.com/types-of-squirrels/#fxtoc-how-to-identify-different-squirrel-species
National Park Service. Eastern Gray Squirrel. https://www.nps.gov/bith/learn/nature/eastern-gray-squirrel.htm
Research on Chipmunks and Squirrels. SCIENCEINSIGHTS. https://enjoythewild.com/types-of-squirrels/#fxtoc-how-to-identify-different-squirrel-species
Walters, Andy. Squirrels as Seed Dispersers: Nature’s Tiny Gardeners at Work. (Updated 2025, Oct. 07) https://petshun.com/article/how-do-squirrels-disperse-seeds
Young, Laura. Do chipmunks and squirrels get along? (2025, November 30) https://iere.org/do-chipmunks-and-squirrels-get-along/
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