EASTERN GRAY SQUIRREL & FOX SQUIRREL: Eastern Gray (Sciurus carolinensis) Fox (Sciurus niger) 

Conflicts with humans can occur when squirrels feed on sweet corn, tomatoes, and other vegetables, or when they dig and eat flower bulbs and newly planted seeds. High squirrel populations can also affect commercial nut production, especially of walnuts and pecans. Because squirrels are rodents, they constantly chew to wear down their always-growing incisor teeth, behavior that can damage wooden decks, exterior siding, fencing, and electrical wiring. Individual squirrels sometimes gnaw into the attics of homes, causing water and structural damage, and damage to electrical wiring.

 

Identification

Among the members of the Squirrel Family living in Missouri, the Eastern gray and fox squirrels are the most common. Their common names are descriptive of the general coat color-the grayish of one, and the "reddish fox" coloration of the other. The gray squirrel varies in length from 14-21 inches (355-533 mm) and in weight from 3/4-1 1/2 pounds (340-680 g); the fox squirrel is generally larger, having a length from 19-29 inches (482-736 mm) and a weight from l-3 pounds (453-1,360 g).

 

Range

Fox squirrels occur in much of the eastern and central United States, as well as in several locations in the West, where they have been introduced. Eastern gray squirrels have a similar range to that of fox squirrels but do not occur in many western areas of the fox squirrel’s range. They have been introduced in several locations in the West.

 

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 habitat over much of their range, especially in the West. In Georgia and Florida, fox squirrels seem to prefer pine timber.

 

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.

 

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. Young squirrels may breed only once in their first year. The gestation period is 42 to 45 days. 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.About 3 young comprise a litter. At birth they are hairless, blind, and their ears are closed. Newborns weigh about 1/2 ounce (14 g) at birth and 3 to 4 ounces (84 to 112 g) at 5 weeks. Young begin to explore outside the nest about the time they are weaned at 10 to 12 weeks. At weaning they are about half of their adult weight.Home range size depends on the sea- son and availability of food. It may vary from 1 to 100 acres (0.4 to 40 ha). Squirrels move within their range according to availability of food. They often seek mast-bearing forests in fall and favor tender buds in elm and maple forests in the spring.During fall, squirrels may travel 50 miles (80 km) 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 mites, fleas, and internal parasites are common. Squirrel hunters often notice botfly larvae (called “wolves” or “warbles”) protruding from the skin. These fly larvae do not impair the quality of the meat for eating.Squirrels are a food source for hawks, owls, snakes, and several mammalian predators. Predation seems to have little effect on squirrel populations.Typically about half the squirrels in a population die each year. In the wild, squirrels over 4 years old are rare, while in captivity individuals may live 10 years or more. Both fox and gray squirrels are active during the daytime hours.

 

Damage and Damage Identification

Squirrels may occasionally damage forest trees by chewing bark from branches and trunks. Fox squirrels damage loblolly and other pines.Squirrels may eat cones and nip twigs to the extent that they interfere with natural reseeding of important forest trees. In forest seed orchards, such squirrel damage interferes with commercial seed production.In nut orchards, squirrels can severely curtail production by eating nuts prematurely and by carrying off mature nuts. In New England fruit orchards, squirrels may eat ovaries of cherry blossoms and destroy ripe pears. Gray and fox squirrels may chew bark of various orchard trees.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.

 

Damage Prevention and Control Methods

In Missouri, squirrels are classified as game mammals and are protected by regulated hunting seasons. Taking squirrels during the prescribed season can help control their numbers. Damage-causing squirrels may be controlled to prevent further damage. Control methods can include exclusion, habitat modification, trapping and removal. Our technicians will help you determine the best options for your situation.

 

• Exclusion - Prevent squirrels from climbing isolated trees and utility poles by encircling them with a two-foot-wide collar of smooth metal 6 feet above ground. Attach the collar with encircling wires held together with springs to allow for tree growth. Trees adjacent to buildings should be trimmed to prevent squirrels from jumping onto roofs. Exclude squirrels from buildings by closing all openings with half-inch wire mesh, taking care to ensure that no squirrels are trapped inside because additional damage will result when the animal chews its way out. If young may be present, delay repairs until the young have matured and exited.Prevent travel on overhead wires by installing a two-foot section of lightweight, 2- to 3-inch-diameter plastic pipe. Slit the pipe lengthwise and place it over the wire. The pipe will rotate with the weight of the squirrel, causing it to tumble. WARNING: Due to the danger of electrical shock, this should only be attempted by a qualified electrician, utility company representative, or other professional.An electric fence can exclude squirrels from vegetable gardens.

• Habitat Modification - Trim limbs and trees to 6 to 8 feet (1.8 to 2.4 m) away from buildings to prevent squirrels from jumping onto roofs.In backyards where squirrels are causing problems at bird feeders, consider providing an alternative food source. Wire or nail an ear of corn to a tree or wooden fence post away from where the squirrels are causing problems.In high-value crop situations, it may pay to remove woods or other trees near orchards to block the “squirrel highway.” 

• Repellents - Naphthalene (moth balls) may temporarily discourage squirrels from entering attics and other enclosed spaces. However, it can cause severe distress to people, it’s use in attics of occupied buildings is not recommended. Supplement this method with lights. A cat in the attic may also discourage squirrels.Ro-pel is a taste repellent that can be applied to seeds, bulbs, and flowers; trees and shrubs; poles and fences; siding and outdoor furniture. Capsaicin is also a taste repellent, registered for use on maple sap collecting equipment.Polybutenes are sticky materials that can be applied to buildings, railings, downspouts, and other areas to keep squirrels from climbing, they can be messy.

• Trapping - Squirrels are relatively easy to catch in traps, but it takes the proper trap to capture one. Translocation of tree squirrels is a questionable practice because of the stress placed on transported and resident squirrels and concerns regarding the transmission of diseases. For best and quickest results, have an experienced professional perform trapping. There are many effective methods for trapping squirrels, however, a great deal of experience is required to effectively trap a squirrel. For homeowners with pets, a box or cage-type trap is usually the preferable alternative to a foothold trap. Body-gripping traps are not allowed for dry-land sets in Missouri, but in locations such as an attic they may be set 6 feet or more above ground. Foothold traps are effective but require special skill and experience. Many people oppose trapping with foothold traps, especially in urban situations. The most common objections to foothold traps include the perception that traps are cruel and inhumane, and concern over catching non-target animals, especially pets. When used properly, traps are effective, selective, and safe, especially when used by an experienced trapper. Restrictions on use apply and our technicians will determine the best option for your situation while following all applicable laws and regulations.  

• Shooting - Squirrel populations can be controlled by shooting. However, in most situations it is not a practical solution. Squirrels are nervous and alert, so they make difficult targets. Safety is a critical factor that in some circumstances may preclude the use of firearms (for example, local laws may prohibit shooting, or neighbors may be too close). Shooting is best left to professionals. In many urban areas, firearms may not be discharged, in most situations local authorities have regulations and restrictions regarding the use of firearms.

• Other Methods - Often several control methods used simultaneously are more successful than a single method. For example, to remove a squirrel from an attic, watch squirrels to determine where they enter. Then use repellents and lights to drive them out. After squirrels appear to have left the building, use appropriate exclusion methods to keep them out. One or more baited traps will catch squirrels that are accidentally closed in. This last step is very important because locked-in squirrels may cause damage when they try to chew their way out.Squirrel damage in yards, gardens, forests, and orchards is often very difficult to control. During population highs, new squirrels arrive quickly to replace those shot or trapped.

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Economics of Damage and Control

Squirrels cause economic losses to homeowners, nut growers, and forest managers. The extent of these losses is not well known.Squirrels caused 177 power outages in Lincoln, Nebraska, in 1980, which was 24% of all outages. Estimated annual costs were $23,364 for repairs, public relations, and lost revenue. In Omaha, in 1985, squirrels caused 332 outages costing at least $47,144. After squirrel guards were installed over pole- mounted transformers in Lincoln in 1985, annual costs were reduced 78% to $5,148.