ISSUED: 10-90
Thomas G. Barnes

Kentucky has three species of tree squirrels: eastern gray (Sciurus carolinensis), northern fox (Sciurus niger), and flying (Glaucomys volans). Gray and fox squirrels are game species, whereas flying squirrels are not a game species. Because flying squirrels seldom cause problems for homeowners, they are not discussed in this publication.
Fox and gray squirrels often come into conflict with humans when they take up residence in an attic, eaves or walls of a house. Squirrels sometimes cause damage by gnawing and removing bark or fruits from valuable fruit and nut producing trees, ornamental trees and shrubbery or by feeding on corn, tomatoes, strawberries and other seeds or mature fruits in the garden.
Tree squirrels are the number one game animals pursued by Kentucky sportsmen, but they are protected by Kentucky law. You must contact your local conservation officer before attempting any control measures.

The eastern gray squirrel is the most common tree squirrel found in Kentucky. These medium-sized rodents have a bushy tail. They are 16 to 20 inches long and weigh 1 to 2 pounds. Gray squirrels vary in color from gray to brownish gray with a white belly. Completely black (melanistic) and white (albino) forms are also encountered occasionally.
The northern fox squirrel is Kentucky's largest tree squirrel. Fox squirrels measure 18 to 27 inches, including their bushy tail, and weigh 1 3/4 to 2 1/4 pounds. Fox squirrels are typically grizzled gray with a touch of yellow or orange upper parts and pale yellow to bright orange underparts. The fox squirrel's tail usually has numerous yellow-tipped hairs, while gray squirrels have white-tipped tail hairs.

Animal Biology and Facts
Both fox and gray squirrels are common in Kentucky. The favorite haunts of gray squirrels are largely forested habitats dominated by oak and hickory trees and city parks or suburban yards. Fox squirrels like relatively open country with oak, hickory and walnut trees scattered along fence rows or occurring in small groves.
Squirrels require large old trees which produce their favorite foods: acorns, hickory nuts, walnuts and Osage orange fruits. During the spring and summer when nuts are scarce, squirrels eat tree buds, fruits, berries and succulent green plant material. In the fall they are very busy collecting nuts and storing them for future use. Old mature trees are also necessary for nesting because squirrels prefer nesting in tree cavities, leaf-nests high in a tree or man-made den boxes.
Squirrels are active during the day. Most activity occurs in the early morning and late afternoon to early evening. Squirrels do not hibernate and are active year round. During late December through January and June through July, squirrels become very active and noisy as they prepare to mate.
Squirrels typically breed when they are one year old. Three to four blind and naked young are born in March/April and September after a 42- to 45-day gestation period. Newborn squirrels weigh about one-half ounce and open their eyes after about 32 days. Young begin exploring outside the nest when they are weaned at 10 to 12 weeks of age.
Home range and movements of squirrels vary widely. Most activity is concentrated within several acres although squirrels have been reported to range from 1 to 100 acres. One study reported squirrels traveled 50 miles during the fall in search of suitable habitat.
Squirrel populations periodically rise and fall and are intricately linked to the quantity and quality of available habitat. Like most small game species, squirrels have high reproductive and death rates. Normally more than 50% of the squirrels in a population die each year. Squirrels are a favorite food of many predators, including hawks, owls, snakes, foxes, house cats and dogs. Squirrels are also susceptible to a variety of parasites and diseases, including ticks, mange mites, fleas and internal parasites. Most squirrels in the wild never reach four years old.

Preventing and Controlling Tree Squirrel Damage
The best long-term solution to managing squirrel problems in the home is to exclude or "build them out" of a building or attic. Because squirrels are rodents and have large front teeth, you must use 1/4 or 1/2-inch hardware cloth or 26 gauge metal when excluding squirrels from buildings. Do not use steel wool or window screening; the squirrels can chew through it.
The best way to eliminate squirrels that have entered a building is to find all their entrances and travel routes. Be sure to look for eave openings, attic vents, loose flashing around chimneys and pipes and openings around cables. Plug all entrances except one, and set a trap at the open entrance (see section on trapping below). Once the squirrels have been eliminated from the building, be sure to repair any damage they caused. Then use the preventive measures outlined below.
To prevent further damage, trim all trees which have limbs within eight feet of the building. Squirrels can be discouraged from climbing trees if you put a band of two-foot-wide sheet metal six feet away from the bottom of the tree. Remove any branches less than six feet from the ground to prevent squirrels from jumping onto them. If the squirrels are gaining access via telephone or electrical wires, put a two-foot section of lightweight 2- to 3-inch diameter plastic pipe over the wire by slitting the pipe lengthwise and placing it over the wire. Be careful not to touch the wire. The pipe will rotate on the wire causing squirrels to tumble.
Squirrels may temporarily vacate an attic and give you enough time to seal entrances if you place mothballs correctly throughout the attic. Use one pound of mothballs per 100 square feet of attic space. Because the mothball vapors are heavier than air, they must be suspended in baseball-size clumps close to the damaged area. Using old pantyhose is an inexpensive, effective way to do this.
One method of controlling and preventing squirrel damage is to reduce the population through shooting or trapping. In rural areas squirrel populations can be reduced effectively by hunting. You must have a valid Kentucky hunting license to shoot squirrels. If you hunt at times other than normal Kentucky hunting seasons, you must contact your local conservation officer before killing any squirrels. Because squirrels are most active during the morning and evening, concentrate your hunting activities during these periods. Many types of firearms are capable of taking squirrels, but a shotgun loaded with #6 shot shells or a .22 caliber rifle is most effective.
A variety of traps can be used to catch squirrels. If you know the squirrels' entry point and you can easily reach it without endangering yourself, place a #110 conibear trap directly over the open entrance. As the animal passes through the opening, it will be killed instantly.
Squirrels can also be captured with live cage traps (Figure 1 ). To be effective, these traps must be pre-baited and wired open for several days before trapping. A variety of baits works well, including peanut butter, walnuts, pecans, apple or orange slices, corn and sunflower seeds. To prevent squirrels from returning, take trapped squirrels at least 5 to 10 miles from the capture site before releasing them. If squirrels are entering an attic where there is space to set a live trap, place the trap immediately behind the opening and catch the squirrel as it enters the building. Do not remove squirrels when young are present.
One box-type of trap has been effective in California. This trap, shown in Figure 2a, Figure 2b and Figure 2c is placed in adjacent trees. A final method of trapping gray squirrels is to use rat-snap traps nailed to a tree or house 15 to 20 feet above ground. The traps should be baited with peanut butter or sweet corn.
No poisons or fumigants are registered for controlling tree squirrels in Kentucky. One method of keeping squirrels from browsing on trees and gnawing on wood is to use a chemical repellent. Repellents do not stop gnawing damage but do reduce the severity of damage. The best repellent is one containing Thiram. Always follow label instructions for using any chemical substance.
Old reports found in the literature suggest repellents containing polybutenes can be used to repel squirrels. The substance burns the squirrels' feet. The following substances can be sprayed on wood to repel squirrels: ( 1 ) One pound of copper napthenate mixed in 2 1/2 quarts of mineral spirits. (2 ) Three pounds asphalt emulsion and 2 pounds copper carbonate mixed in 2 quarts of water. (3) One teaspoon of Lysol® or 3 ounces epsom salts mixed in 1 gallon of water. Several of these solutions may discolor wood; treat a small area hidden from view first to determine the amount of discoloration.
Be patient and persistent. Wildlife damage problems are rarely solved quickly. Once the squirrel problem has been eliminated, be sure to repair any damage to remove the attractive feature and prevent further damage.

About the Author
Tom Barnes has worked at the University of Kentucky's Department of Forestry for two years as an Extension specialist in wildlife. After working on his master's degree at South Dakota State University, he worked in the state Game, Fish and Wildlife department and at the U.S. Fish and Wildlife Service. He also gained experience in the field while working at U.S.D.A. Animal Damage Control. He has published information on mice, rabbit and vole damage to trees. His Ph.D. from Texas A&M is in wildlife management.