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- In some of the habitats where it has been introduced, the grey squirrel has displaced several of its native cousins thanks to its larger size, greater strength, and the ability to digest nutrient-rich seeds more efficiently.
- Grey squirrels do not hibernate during winter; unlike other rodents or squirrels, the grey squirrel does not possess the ability to retain a high level of body fat in order to sustain itself through the cold season without eating.
- Grey squirrels are scatter hoarders: they bury their seeds all over the place, often forgetting where. Fortunately, their forgetfulness is, according to scientists, the main way oak forests grow and spread.
- The grey squirrel is considered a “living fossil” because its current shape has changed very little from the primitive squirrel morphotype.
- Although they can reach 12 years in the wild and 20 in captivity, grey squirrels barely make it past their first two years due to predation and road kill.
Native to Canada and the United States, the Eastern grey squirrel is medium-sized, with no sexual dimorphism in size and color (males and females have about the same size and coloration). The hairs on their body are white, brown, and black, but are tipped with white and give the impression they are grey. It is also not uncommon to see an Eastern grey squirrel that’s entirely black (common in the northern populations of Ontario and Quebec) or entirely white (rarely seen in the southern United States). The color of the fur on their dorsal side ranges from dark grey to pale grey, but also has a lot of red tones, while their chest and stomach are lighter. The fur is thicker in winter and may change with the season.
The bushy tail is one of the most striking things about the Eastern grey squirrel and fulfills several important functions. During the winter season, the squirrel wraps its tail over the body to get protection from cold and rain, while in the summer, it can make it act as a sunshade by pumping more blood into it and allowing its body temperature to decrease. When jumping from high trees, the tail is used as a counterbalance or even as a sort of parachute, slowing the animal’s descend.
Differentiating between the Red and Grey Squirrel
Although there are certain similarities between the red squirrel and the grey squirrel, the two differ in:
- Size: The red squirrel weighs between 270 and 340 g, while the grey squirrel is nearly twice as big, weighing 540-660 g.
- Appearance: Contrary to their name, red squirrels aren't usually red; the color of their fur ranges from black to light brown with white on the chest and stomach. A distinctive characteristic is their long ear tufts, more visible during the cold season. The grey squirrel's coat is, indeed, grey, with brown in the upper body and white on their underside, but can also be brown, black, or white. The ear tufts are lacking.
- Diet: The two squirrels eat pretty much the same things - tree seeds and the buds, flowers, and shoots of deciduous and coniferous trees, as well as fungi, berries, and birds' eggs. However, unlike the grey squirrel, the red squirrel cannot digest acorns and other seeds high in tannin, which puts it at a disadvantage in hard winters.
Diet, Behavior, and Habits
The Eastern grey squirrels’ diet consists primarily of nuts, buds, shoots, and flowers of oaks, hickory, walnut, pecan, and other deciduous trees. They also love maple, elm, wild cherry, black gum, hazelnut, and gingko tree seeds and fruits; cedar, pine, hemlock, and spruce are also on their menu, along with a wide assortment of fungi and herbaceous plants. Squirrels are, after all, opportunistic feeders, meaning that they’ll feed on anything available. In the summer, they prey on insects, frogs, and birds’ eggs, whose nutrient-rich content is essential for the development of juveniles. When food is scarce, especially in winter, grey squirrels will strip bark from trees to get to the sapwood.
Squirrels either build nests near the top of large trees, especially pine, maple, and oak, (where they are able to find a good nesting site in the forked branches of trees or on limbs) or in dens. The nests are usually located high above the ground and are sustained by a platform of twigs and protected by an outer covering of leaves. The inside is lined with moss, grass, and sometimes bird feathers. Dens are mainly used for overwintering and as brood chambers.
There are two breeding seasons, one in January-February and the second in June-July, each lasting for nearly 3 weeks. If conditions are favorable, squirrels can produce 2 liters per year with 2-4 young each (up to 8). Males fight with each other for the ability to mate with a female; females can mate with one or more males. Pregnancy lasts about 44 days, after which the newborn emerge - naked, having only their vibrissae (whiskers), and weighing no more than 18 g. They are able to leave the nest after 7 weeks and, by the end of the 10th week, are able to feed independently and eat solid food. The young are silver in color and get their adult coat after 3-4 months.
Grey squirrels communicate through a wide range of sounds and positions, also using their strong sense of smell to identify things such as the stress levels and reproductive state of other squirrels. 11 different types of calls have been identified so far, along with scolding noises and tail flicking movements directed at other squirrels or predators.
- Displace native species in regions where they have been introduced (in most of England and Wales, for instance, grey squirrels have spread rapidly and displaced the native red squirrel)
- Strip bark from the stem and branches of trees, reducing the value of the crop and leading to the loss of more vulnerable species
- Eat the above-ground parts of crops as soon as they emerge in the spring; the plants can also be damaged by the amount of soil they are covered with during squirrels' burrowing activities
- Burrows weaken stock dams and levees and speed up soil erosion in mountainous regions
- When it comes to some crops such as alfalfa, they compete with livestock for forage (one study showed that nearly 100 squirrels can eat as much forage as one sheep per day)
- Strip the bark off trees, particularly maple, sycamore, and beech, leading to timber discoloration and exposing them to fungal attacks and other diseases
- Eat the buds, fruit, nuts, and, twigs, and flowers of fruit trees
- Curtail production of nuts in nut orchards by eating and taking nuts away
- Dig up and eat flower bulbs and corms
- Dig up tiny holes in lawns to hide or search for nuts
- Gnaw on wood decks, furniture, mail posts, fences, and any wooden or plastic things
- Gnaw on wires and power lines, occasionally shorting out transformers and causing power outages
- Compete with birds at the bird feeder during the cold season
- They are important predators in their ecosystem and hosts to various parasites
Through their scatter hoarding behavior, they indirectly have a major role in forest regeneration
- They contribute to forest growth and health by distributing truffle fungal spores
They are prey for other animals including foxes, bobcats, wolves, and coyotes
In some regions, they are still considered an important source of food and fur
They are valuable to nature watchers, ranking second in value after birds
Management and Control
Squirrels will quickly take up residence inside buildings if there are access points to sheltered areas such as attics and crawlspaces. Gnawing and scratching are the first signs of their presence, as well as cardboard and dried vegetation brought in to build their nest. Here are the main methods used for the elimination and prevention of squirrels inside structures:
You can prevent squirrels from getting inside the house by sealing all access points to attics, chimneys, and other locations inside the house that can make a good nesting site. Make a thorough inspection of the exterior of your house, specifically gaps and places where the wood has rotten or where utility cables enter your building, and seal all entrances with hardware cloth (available at hardware and box stores) and other suitable materials. After all openings are closed, use sheet metal to cover the trunks of nearby trees 6-8 feet above the ground and consider installing customized wire mesh fences to prevent squirrels from entering gardens and orchards.
To prevent squirrels from getting inside structures via the roof, trim tree branches that can provide easy passage. If squirrels are competing with birds for feed around your bird feeder, provide corn separately for them and grease the pole with oil to discourage them from climbing.
Repellents have limited effectiveness; they mainly work by discouraging squirrels from getting inside attics and crawlspaces. Naphthalene can be used in places with low human traffic, and capsaicin or ro-pel can be sprayed on seeds, bulbs, poles, fences, and outdoor furniture. Polybutenes can be placed on poles and the exterior of buildings to prevent squirrels from climbing.
Trapping is very effective for eliminating small to medium populations, and there is a variety of trap types (leghold traps, box traps, cage traps, glue traps, etc.) for all squirrel sizes. In some regions, a permit may be required from your local state wildlife agency, since squirrels are considered game species.
At the bird feeder:
- Put a single kind of seed into a bird feeder to prevent birds from dumping the seeds they don't like on the ground
- Modify your feeder so that spilled seeds are collected into a tray before getting on the ground; make sure you regularly check them to prevent overflowing
- Place feeders away from trees, poles, and wires that could serve as launching points for squirrels
- Surround your feeder with a wire cage and make the entry small enough to be accessed only by the birds you plan to feed (and keep intruders such as starlings, pigeons, and squirrels away)
- Eliminate sources of water from your garden (leaking and standing), as well as incidental food such as seeds from a local bird feeder
- Install fencing to protect garden beds and plants and add a layer of wire mesh underneath and above the beds for extra protection
- Spray burrows and plants being eaten with cayenne pepper and repellents containing capsaicin
- Place traps near burrows' entry points and other areas where squirrel activity is present; bait them with peanut butter, bacon, or apple