Jeffrey J. Jackson Extension Wildlife Specialist Warnell School of Forest Resources TREE SQUIRRELS University of Georgia Athens, Georgia 30602 Fig. 1. Fox squirrel, Sciurus niger Damage Prevention and Plastic tubes on wires may prevent Fumigants access to buildings. Control Methods None are registered. Cultural Methods Trapping Exclusion Remove selected trees or their Leghold traps. Install sheet metal bands on isolated branches to prevent access to trees to prevent damage to structures. Box and cage traps. developing nuts. Repellents Rat snap traps. Close external openings to buildings to Naphthalene (moth balls), Ro-pel, Box choker traps. stop damage to building interiors. capsaicin, and polybutenes are Shooting Place an 18-inch (46-cm) section of registered for controlling tree 4-inch (10-cm) diameter plastic pipe squirrels. Effective where firearms are permit- ted. Use a shotgun with No. 6 shot or a one-way door over openings to Toxicants allow squirrels to leave and prevent or a .22-caliber rifle. them from returning. None are registered. PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994 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 B-171 Great Plains Agricultural Council Wildlife Committee Identification In this chapter tree squirrels are divided into three groups: large tree squirrels, pine squirrels, and flying squirrels. Large tree squirrels include fox (Sciurus niger), eastern gray (Sciurus carolinensis), western gray (Sciurus griseus), and tassel-eared (Sciurus aberti) squirrels. Fox squirrels (Fig. 1) measure 18 to 27 inches (46 to 69 cm) from nose to tip of tail. They weigh about 1 3/4 pounds (787 g) to 2 1/4 pounds (1,012 g). Color Fig. 3. Range of the eastern gray squirrel (dark) varies greatly, from all black in Florida Fig. 2. Range of the fox squirrel (dark) and and western gray squirrel (light) in North to silver gray with a white belly in tassel-eared squirrel (light) in North America. America. Maryland. Georgia fox squirrels usu- ally have a black face. Ohio and Michi- gan fox squirrels are grizzled gray-brown above with 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. Black ones are common in some northern parts of their range. Eastern gray squirrels measure 16 to 20 inches (41 to 51 cm). They weigh from 1 1/4 pounds (567 g) to 1 3/4 pounds (794 g). The western gray squirrel is gray Fig. 4. Range of the red squirrel (dark) and Fig. 5. Range of the northern flying squirrel above with sharply distinct white Douglas squirrel (light) in North America. (dark) and southern flying squirrel (light) in underparts. Size is similar to that of North America. the eastern gray squirrel. Two species of flying squirrels occur in where they have been introduced Tassel-eared squirrels are similar in North America. The southern flying (Fig. 2). size to gray squirrels and have several squirrel (Glaucomys volans) is 8 to 10 Eastern gray squirrels have a similar color phases. The most common is inches (20 to 25 cm) long. The northern range to that of fox squirrels but do gray above with a broad reddish band flying squirrel (Glaucomys sabrinus) not occur in many western areas of the down the back. Black tufted ears are averages 2 inches (5 cm) longer. It can fox squirrel’s range. They have been their most distinguishing characteristic be difficult to distinguish between the introduced in several locations in the (the tufts are larger in winter, about 1 two; both may be various shades of West (Fig. 3). inch [2.5 cm]). gray or brown above and lighter There are two species of pine squirrels: below. A sharp line of demarcation Western gray squirrels are confined to the red squirrel (Tamiasciurus separates the darker upper color from west coast states and a small portion of hudsonicus) and Douglas pine squirrel the lighter belly. The most distinctive western Nevada (Fig. 3). characteristics of flying squirrels are (Tamiasciurus douglasii). Pine squirrels Pine squirrels occur across northern the broad webs of skin connecting the are 10 to 15 inches (25 to 38 cm) in total North America south into the Appala- fore and hind legs at the wrists, and length and weigh 1/3 to 2/3 pounds chians and Rockies, and on the west the distinctly flattened tail. (151 to 303 g). Red squirrels are red- coast. brown above with white underparts. Douglas squirrels are gray-brown Range Red squirrels are often associated with above with yellowish underparts. Both coniferous forests. The Douglas squir- species have small ear tufts and often Fox squirrels occur in much of the rel is restricted to the west coast from have a black stripe separating the dark eastern and central United States, as southwestern British Columbia south upper color from the light belly. well as in several locations in the West, through the Sierras to northern Baja California (Fig. 4). B-172 The tassel-eared squirrel is restricted Pine squirrels are often heavily depen- During fall, squirrels may travel 50 to Ponderosa pine forests in the South- dent on coniferous forests for cones miles (80 km) or more in search of bet- west, usually at altitudes above 5,000 and buds but will also eat a variety of ter habitat. Squirrel populations peri- feet (1,500 m). It occurs in portions of other foods common to gray and fox odically rise and fall. During periods Wyoming, Colorado, New Mexico, squirrel diets. Douglas squirrels of high populations, squirrels—espe- Arizona, and Utah (Fig. 2). depend largely on Ponderosa pine for cially gray squirrels—may go on mass food. Flying squirrels’ food habits are emigrations. At such times many The northern flying squirrel occurs generally similar to those of other animals die. across northern North America. Its squirrels. However, they are the most range extends south into the Appala- carnivorous of all tree squirrels. They Fox and gray squirrels are vulnerable chians and Rockies. The southern fly- eat bird eggs and nestlings, insects, to numerous parasites and diseases. ing squirrel occurs in the central and and other animal matter when avail- Ticks, mange mites, fleas, and internal eastern United States (Fig. 5). able. Flying squirrels often occupy bird parasites are common. Squirrel hunt- houses, especially bluebird houses. ers often notice bot fly larvae (called Habitat “wolves” or “warbles”) protruding General Biology, from the skin. These fly larvae do not Fox squirrels and gray squirrels impair the quality of the meat for inhabit the same kinds of forests, both Reproduction, and eating. hardwood and coniferous, over much Behavior Squirrels are a food source for hawks, of their range. Gray squirrels are more owls, snakes, and several mammalian abundant where a high percentage of Fox and gray squirrels breed when predators. Predation seems to have land is forested. In areas with 10% for- they are 1 year old. They breed in mid- little effect on squirrel populations. est cover, fox and gray squirrel popu- December or early January and again lations may be equal. Fox squirrels in June. Young squirrels may breed Typically about half the squirrels in a prefer oak-hickory habitat over much only once in their first year. The gesta- population die each year. In the wild, of their range, especially in the West. tion period is 42 to 45 days. squirrels over 4 years old are rare, In Georgia and Florida, fox squirrels while in captivity individuals may live During the breeding season, noisy seem to prefer pine timber. The west- 10 years or more. mating chases take place when one or ern gray squirrel prefers mixed hard- more males pursue a female through The biology of other North American woods and conifers and dry open the trees. squirrels has much in common with hardwoods. Tassel-eared squirrels are that of fox and gray squirrels, although strongly associated with Ponderosa They nest in tree cavities, human- most other species have one breeding pine. Pine squirrels prefer coniferous made squirrel boxes, or in leaf nests. season per year. Flying squirrels are forests but also occur in mixed conifer Leaf nests are constructed with a unique in that they are active at night. and hardwood forests, or sometimes frame of sticks filled with dry leaves All other species are active during the in hardwood habitats. and lined with leaves, strips of bark, day. corn husks, or other materials. Sur- Food Habits vival of young in cavities is higher than in leaf nests. Cavities are the pre- Damage Fox and gray squirrels have similar ferred nest sites. Squirrels may occasionally damage food habits. They will eat a great vari- About 3 young comprise a litter. At ety of native foods and adapt quickly forest trees by chewing bark from birth they are hairless, blind, and their branches and trunks. Pine squirrels to unusual food sources. Typically, ears are closed. Newborns weigh they feed on mast (wild tree fruits and damage Ponderosa pine, jack pine, about 1/2 ounce (14 g) at birth and 3 to and paper birch. In the Southeast, fox nuts) in fall and early winter. Acorns, 4 ounces (84 to 112 g) at 5 weeks. hickory nuts, walnuts, and osage squirrels damage loblolly and other Young begin to explore outside the pines. orange fruits are favorite fall foods. nest about the time they are weaned at Nuts are often cached for later use. In 10 to 12 weeks. At weaning they are These species and others may eat late winter and early spring they pre- about half of their adult weight.