TREE SQUIRRELS

Damage Prevention and Control Methods

Exclusions

• Close external openings to building to stop damage to building interiors

Cultural Methods

• Remove selected trees or their branches to prevent access to structure

Trapping

Identification
There are 3 types of large tree squirrels in this area; the fox squirrel, eastern gray squirrels, and red squirrels.

Fox squirrels measure 18-27 inches from nose to tip of tail. They weigh about 1 3/4 pounds to 2 1/2 pounds. Color varies greatly, from all black to grizzled gray-brown above an orange underside. Sometimes several color variations occur in a single population

Eastern gray squirrels are also variable in color. Some have a distinct reddish cast to their gray coat. The squirrels measure 16 to 20 inches and weigh on average 1 1/2 pounds.

The red squirrel is a member of the pine squirrel species. They are red-brown above with white underparts. Red squirrels have small ear tufts and often have a black stripe separating the dark upper color from the light belly.

Habitat
Fox squirrels and gray squirrels inhabit the same kinds of forests, both hardwood and coniferous, over much of their range. Gray squirrels are more abundant where a high percentage of land is forested. In areas with 10% forest cover, fox and gray squirrel populations may be equal. Fox squirrels prefer oak-hickory habitats over much of their range. Red squirrels prefer coniferous forests but also occur in mixed conifer and hardwood forests, or sometimes in hardwood habitats.

Food Habits
Fox and gray squirrels have similar food habits. They will eat a great variety of native foods and adapt quickly to unusual food sources. Typically, they feed on mast (wild tree fruits and nuts) in fall and early winter. Acorns, hickory nuts, walnuts, and osage orange fruits are favorite fall foods. Nuts are often cached for later use. In late winter and early spring they prefer tree buds. In summer they eat fruits, berries, and succulent plant materials. Fungi, corn, and cultivated fruits are taken when available. During population peaks, when food is scarce, these squirrels may chew bark from a variety of trees. They will also eat insects and other animal matter.

Red squirrels are often heavily dependent on coniferous forests for cones and buds but will also eat a variety of other foods common to gray and fox squirrel diets.

General Biology, Reproduction, and Behavior
Fox and gray squirrels breed when they are 1 year old. They breed in mid-December or early January and again in June. The gestation period is 42 to 45 days. About 3 young comprise a litter. At birth they are hairless, blind, and their ears are closed. Newborns weigh about 1/2 ounce at birth and 3 to 4 ounces at 5 weeks. Young begin to explore outside the nest about the time they are weaned at 10 to 12 weeks.

During the breeding season, noisy mating chases take place when one or more males pursue a female through the trees.

They nest in tree cavities, human-made squirrel boxes, or in leaf nests. Leaf nests are constructed with a frame of sticks filled with dry leaves and lined with leaves, strips of bark, corn husks, or other materials. Survival of young in cavities is higher than in leaf nests. Cavities are the preferred nest sites.

Home range size depends on the season and availability of food. It may vary from 1 to 100 acres. Squirrels move within their range according to availability of food. During the fall, squirrels may travel 50 miles or more in search of better habitat. Squirrel populations periodically rise and fall. During periods of high populations, squirrels - especially gray squirrels - may go on mass emigrations. At such times many animals die.

Fox and gray squirrels are vulnerable to numerous parasites and diseases. Ticks, mange bites, fleas, and internal parasites are common. Squirrels are a food source for hawks, owls, snakes, and several mammalian predators. Predation seems to have little effect on squirrel population. Typically about half the squirrels in a population die each year. In the wild, squirrels over 4 years old are rare.

The biology of the red squirrel is very similar to the fox and gray squirrels, although they only have one breeding season per year.

Damage and Damage Identification
Squirrels may occasionally damage forest trees by chewing bark from branches and trunks.

In nut orchards, squirrels can severely curtail production by eating nuts prematurely and by carrying off mature nuts. In residential areas, squirrels sometimes travel power lines and short out transformers. They gnaw on wires, enter buildings, and build nests in attics. They frequently chew holes through pipelines used in maple syrup production.

Squirrels occasionally damage lawns by burying or searching for and digging up nuts. They will chew bark and clip twigs on ornamental trees or shrubbery planted in yards. Often squirrels take food at feeders intended for birds. Sometimes they chew to enlarge openings of bird houses and then enter to eat nestling songbirds. In gardens, squirrels may eat planted seeds, mature fruits, or grains such as corn.

To learn more about our animal control and animal removal services, please contact us.

ACKNOWLEDGEMENTS
The above information was adapted from PREVENTION AND CONTROL OF WILDLIFE DAMAGE with permission of the editors, Scott E. Hygnstrom, Robert M. Timm, and Gary E. Larson (Cooperative Extension Division, Institute of Agriculture and Natural Resources University of Nebraska-Lincoln, United States Department of Agriculture Animal and Plant Health Inspection Service, Animal Damage Control, Great Plains Agricultural Council Wildlife Committee). It is will great gratitude and appreciation that we are able to pass along this useful information.