Grey Squirrel, Sciurus carolinensis

Wisconsin Native Squirrels

Squirrels are nimble, bushy-tailed rodents found all over the world. They belong to the Sciuridae family, which includes prairie dogs, chipmunks and marmots.

There are more than 200 species of squirrels and they are categorized into three types: tree squirrels, ground squirrels and flying squirrels. Wisconsin has 5 native species of squirrel:

  Eastern Grey Squirrel, Sciurus carolinensis
  Eastern Fox Squirrel, Sciurus niger
  Red Squirrel, Tamiasciurus hudsonicus
  Northern Flying Squirrel,Glaucomys sabrinus
  Southern Flying Squirrel, Glaucomys vilans

All five species are popular with people who enjoy watching wildlife, although flying squirrels, because of the nocturnal habits, are rarely seen. As abundant animals low in the food chain, squirrels are important prey species for many mammalian and avian predators.

Why You Should Learn To Love Squirrels

Forest Regeneration

Squirrel reaching from a tree

They are huge contributors in shaping plant composition due to their eating and food saving habit. While they eat seeds and nuts though they have this peculiar habit of burying some of them for future consumption throughout the environment for later, but their forgetfulness helps the ecosystem to thrive.

The seeds or nuts they stored later sprout and grow into trees. After a considerable amount of time this caching leads to altering the composition of the forest. New types of trees become present in the forest. Over a long length of time, the forest can even expand.

Role In The Food Chain

Another important role of squirrels in the ecosystem is being a food source for other animals. They hold a significant place in the natural food chain and are preyed on by several avian and mammalian predators. Squirrels become food for air and land predators.

Indicator Of Forest Health

To determine the health of a forest ecosystem, and to measure how well it is doing, researchers take into account the population of tree squirrels there. Demographics of squirrels are important indicators for a forest’s condition, and these can be studied to determine the impact of climate changes, global warming, logging, fires, and other events on forest habitats.

Eastern Grey Squirrel, Sciurus carolinensis

Eastern Grey Squirrel
Length: 18-21 inches
Tail Length: 8-10 inches
Coloration: Yellowish brown summer coat becomes thicker and gray in winter
Lifespan: 1-2 years
Gestation: 40-44 days
Litter Size: 1-9 (average 2-3)

Range and Habitat

The deciduous forests of Wisconsin provide the optimum habitat for the eastern gray squirrel. Home for an eastern gray squirrel may be a leafy nest, a dome-shaped mass of twigs and leaves with an inner chamber of shredded bark and leaves, or a tree cavity which it seems to prefer.

Diet

The principle foods are seeds and nuts with acorns, beechnuts, butternuts, and hickory nuts providing the mainstay of the autumn and winter diet. Beech and nuts, because of their relative abundance in parts of the Adirondacks, make the greater contribution. The smaller seeds of maples, ashes and basswood are of lesser importance. The buds, flowers, and inner bark of all these species, and others, contribute to the late winter and spring diet. Gray squirrels feed extensively on fungi, berries, and fruits during the summer, especially the fruit of the black cherry.

Eastern Fox Squirrel, Sciurus niger

Eastern Fox Squirrel
Length: 21 inches
Tail Length: 8-10 inches
Coloration: Gray and black fur on its back and orange-colored fur on its belly
Lifespan: Average is 7 months
Gestation: 44 days
Litter Size: 3-4

Range and Habitat

Eastern Fox Squirrels, like other tree squirrels, use trees for escaping from predators. They are fast and agile in the trees. They can readily escape predators on the ground and large birds of prey if they can seek refuge in the trees. Fox squirrels are found in a diverse array of deciduous and mixed forest. Areas with a good variety of tree species are preferred due to variability in mast production.

Diet

A wide variety of foods are taken, ranging from vegetative matter to gall insects, moths, beetles, bird, eggs, and dead fish. Acorn, hickory, walnut, mulberry, and hawthorne seeds are preferred. Food can often become limiting in the winter, so squirrels commonly cache seeds in a scattered fashion for the colder months. Nuts are opened by a levering technique of the lowering incisors, a skill at which squirrels become proficient quickly.

Red Squirrel, Tamiasciurus hudsonicus

Red Squirrel
Length: 10-15 inches
Tail Length: 3-6 inches
Coloration: Reddish back and white underside with dark colored lines
Lifespan: Average is 5 years
Gestation: 35 days
Litter Size: 1-8

Range and Habitat

Red squirrels occupy coniferous forests abundant with conifer seeds, fungi, and interlocking canopies. Populations of red squirrels occur in different habit conditions due to the vastness of their range. They are considered to be primarily arboreal. They can be found in a mixed variety of forests including coniferous, deciduous, and mixed forests and they are also able to thrive in suburban and urban settings, as long as cool, coniferous forests with dense, interlocking canopies and abundant fungal resources are present.

Diet

The Red Squirrel eats a wide-variety of foods including insects, seeds, bark, nuts, fruits, mushrooms and pine seeds or cones. Sometimes it eats insects, young birds, mice and rabbits. A large part of its diet is made up of pine seeds. In the fall, it will cut green pine cones from trees and store them in the ground. It also stores nuts and seeds in piles or middens under logs, at the base of trees and underground.

Northern Flying Squirrel, Glaucomys sabrinus

Northern Flying Squirrel
Length: 10-13 inches
Tail Length: 3-6 inches
Coloration: Silky grey and cinnamon brown fur, with white tipped and grey based belly hairs
Lifespan: Average is 4 years
Gestation: 37-42 days
Litter Size: 1-6

Range and Habitat

Most often found in areas dominated by conifers, northern flying squirrels can also be relatively abundant in deciduous and mixed coniferous/deciduous forests. The Northern Flying Squirrel has been found in diverse areas including regions dominated by spruce, fir, and mixed hemlocks, in beech maple forests, and in areas dominated by white spruce and birch with interspersed aspen groves. The Northern Flying Squirrel often nests in conifers 4-50 feet above the ground. The nests are made of twigs and bark, and they are softened with feathers, fur, leaves, and conifer needles. They clumsy on the ground, but can glide gracefully from tree to tree.

Diet

The Northern Flying Squirrel eats nuts, acorns, fungi, and lichens, supplemented by fruits, buds, sap and the occasional insect and bird egg. Northern Flying Squirrels diverge from many squirrels in that lichens and fungi are a large portion of the diet and are not just supplements. It is thought that northern flying squirrels hoard food for the winter, though this has not been confirmed.

Southern Flying Squirrel, Glaucomys vilans

Southern Flying Squirrel
Length: 11 inches
Tail Length: 3-6 inches
Coloration: grey brown fur on top with darker flanks, and are a cream color underneath.
Lifespan: Average is 4 years
Gestation: 40 days
Litter Size: 2-3

Range and Habitat

Southern Flying Squirrels are commonly found in beech-maple, oak-hickory, and poplar forests.Southern flying squirrels are nocturnal animals. They occasionally display social behavior and can be found in pairs. In order to conserve heat during the winter months, these rodents form groups of 10 - 20 squirrels, which huddle together in a den, typically located in a hollow tree. Southern Flying Squirrels do not hibernate. In spite of their name, these rodents don't fly, but glide. During the 'flight', they are able to avoid trees and other obstacles with ease. Moreover, they can glide from a height of up to 60 feet.

Diet

As omnivorous animals, Southern flying squirrels have a rather diverse diet. They feed upon nuts, acorns, seeds, berries, fruit, moths, june bugs, leaf buds, bark, eggs and cheeks of birds, young mice, insects, carrion as well as fungus.

Further Reading:

 Japanese Beetles: Facts and Control
 YIKES! Jumping Worms
 How To Get Rid Of Ants
 All About Aphids and Their Control
 Voles — Both the Good and the Bad