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 TREE SQUIRRELS
Common names: Eastern gray squirrel / fox squirrel / red (pine) squirrel
Scientific names: Sciurus carolinensis / Sciurus niger /Tamiasciurus hudsonicus
 Biology.
Eastern gray squirrel & fox squirrel
Adult body length (without tail): 8 to 10 inches (gray squirrel);
10 to 15 inches (fox squirrel)
Adult body weight: 1 1/3 to 1 2/3 pounds (gray squirrel);
1 2/3 to 2 1/3 pounds (fox squirrel)
Gestation period: 42 to 45 days
Litters per year: 1 to 2
Litter size: 3 to 5 young (usually 3)
Breeding season: December through January & June
Birthing season: February through March & July through August
Age at which young are weaned: 10 to 12 weeks
Activity period: Daytime
Range: 1 to 160 acres
Primary foods: Seeds, acorns, nuts, fruits, vegetables, live bark
Red (pine) squirrel
Adult body length (without tail): 6 to 8 inches
Adult body weight: 5 to 10 ounces
Gestation period: 35 to 38 days
Litters per year: 1 to 2
Litter size: 3 to 8 young (usually 3)
Breeding season: February through March & July through August
Birthing season: March through May & August through October
Age at which young are weaned: 10 to 12 weeks
Activity period: Daytime
Range: 1 to 100 acres
Foods: Seeds, acorns, nuts, fruits, vegetables, live bark, pine cones
Flying squirrels
Adult body length (without tail): 5 to 6 inches
Adult body weight: 1 1/3 to 3 ounces
Gestation period: 40 days
Litters per year: 1 to 2
Litter size: 3 to 4 young (usually 3)
Breeding season: February through March & June through July
Birthing season: April through May & August through September
Age at which young are weaned: 7 weeks
Activity period: Night
Range: 1 to 100 acres
Primary foods: Insects, seeds, nuts, fruits, vegetables
 Pest status. Tree squirrels and flying squirrels can cause damage or become a nuisance to the homeowner when they use buildings for nesting sites and food storage or they gnaw into attics to take up residence. They also may move into spaces between walls and floors. They often gain access through vents, broken windows, knotholes, and construction gaps under eaves and gables. Occasionally, the chimney and fireplace provide an entry route.
Squirrels have a remarkable ability to destroy wooden shakes and shingles, cedar seeming to be their favorite. The amount of structural damage may at times be severe. They can be particularly destructive to summer or vacation cabins which are vacant during part of the year, as they are free to continue their activities until the owners return. Garages, barns, stables, tool sheds and other buildings often serve as homes for tree squirrels.
Rarely do tree squirrels take up residence inside an occupied building without being seen or heard at once. A possible exception is flying squirrels whose presence in an area may be unsuspected because they are only active at night. The typical evidence of tree squirrels includes droppings, gnawed holes, nest materials, food stores, shells, nut hulls, fruit pits, and other food remnants. If squirrels are in the attic or garage, the occupant will likely hear them moving about, even if one has not seen them.
In backyards and in landscaped areas, squirrels will dig up vegetable and flower gardens, primarily for seeds and bulbs. Seasonally, they will clip flower buds and leaves and often strip the bark from trees and various ornamental plants. They are particularly fond of maturing nuts and fruit; and where only a few trees exist in a backyard, they can literally strip them of a crop of walnuts, hickory nuts, etc. Tree squirrels are fond of burying food items, such as acorns and nuts, and their diggings can be very destructive to turf and other landscaped areas.
Utility companies report that tree squirrels often cause loss of electrical and telephone service by gnawing into cables and stripping insulation. This damage causes shorting, sometimes resulting in fires, or grounding and can be difficult and costly to repair. Power outages cause significant economic losses. Overhead power and communication lines are frequently used by tree squirrels to travel from one site to another. Rodent fleas, ticks and mites are common ectoparasites of tree squirrels. When squirrels take up residence in attics or other parts of a dwelling, their ectoparasites may prove troublesome to humans.
CONTROL
Habitat Modification and Cultural Control
Pruning. Tree branches should be pruned at least six feet from all building surfaces. The removal of tree limbs that overhang the roof will sometimes eliminate access by squirrels. [Any distance of 6 feet or less can be considered an easy jump for most tree squirrels.]
Refraining from feeding. Feeding squirrels and coaxing them to approach dwellings and people is a sure way to encourage nesting in nearby trees or the dwelling itself, if accessible. Those who have squirrels invading or damaging structures should be admonished to refrain from feeding squirrels close to occupied buildings. Likewise, squirrels that routinely gain access to backyard or window bird feeders can be discouraged from continuing their raids as a result of installing squirrel excluder devices on bird feeder poles and brackets, if done correctly.
Physical / Mechanical Control
Exclusion. Exclusion (rodent-proofing) is the best and most permanent solution to squirrels gaining access to dwellings. Sheet metal or wire hardware cloth are most often used to close openings. It is important when closing all possible entry routes not to trap animals inside. Therefore, a thorough trapping effort must precede any exclusion procedure in order to achieve lasting results.
Squirrels may be prevented from climbing trees by attaching a wide metal band or collar around the trunk at least 6 feet from the ground. Aluminum roof flashing, fitted snugly, works very well but must allow for growth to prevent damage to the trees. These collars should be about 18 to 20 inches wide with no gaps or rough surfaces to permit climbing. Collars are useless if tree limbs are within jumping distance of the ground, nearby trees, fences, or other structures accessible to squirrels.
Live-trapping. If the population of tree squirrels must be reduced, trapping is most often the method of choice. Live-catch 24” x 8” x 7” and 16” x 5” x 5” or similar size wire cage traps are very effective. If squirrels are entering the premises via overhead routes such as trees or power lines, traps placed on roof-tops, at gutter level or secured to tree limbs may be the most appropriate settings. For best results in dealing with trap-shy squirrels, traps should be prebaited for several days with the doors secured in the open position; when the bait is readily taken, the traps can be re-baited and set. A wide variety of baits may be acceptable: peanuts, peanut butter, walnuts, pecans, acorns and sunflower seeds have all been effective. Live-catch traps must be checked at least once daily to remove squirrels or to release other animals accidentally captured.
Chemical Control
Repellents. Though not a method employed by Rottler technicians, non-toxic, sticky repellents (e.g., polybutene) may be helpful in discouraging tree squirrels from walking or climbing on some surfaces. Several tacky repellents are currently registered for tree squirrels. The disadvantages to using this method are: 1) the temporary efficacy of these products, 2) unsightliness of dirty and heat-displaced applications and 3) the potential effect on non-target animals and humans.
Toxic baiting. No EPA-registered rodenticides are available for tree squirrel control.
Locations
Serving the St. Louis Metropolitan area since 1956, including
Arnold, Ballwin, Chesterfield, Crestwood, Creve Coeur, Des Peres,
Fenton, Florissant, Kirkwood, Maryland Heights, Overland, St.
Charles, Webster Groves, Wentzville and surrounding areas.
In Illinois: Belleville, Collinsville, Edwardsville, Columbia,
Madison, Waterloo, O’Fallon, Granite City, Alton, St. Clair, Monroe
and surrounding areas.
Columbia & Jefferson City, MO and surrounding areas. |
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