Two species of squirrels live on the islands of the Kodiak Archipelago. The Arctic ground squirrel (Spermophilus parryii) was introduced a few hundred years ago, and the more common red squirrel (Tamiasciurus hudsonicus) was introduced in 1952. The red squirrel population is slowly spreading across Kodiak Island, and biologists estimate at least 10,000 to 15,000 red squirrels now live on Kodiak.
Red squirrels range across Canada and Alaska and south into the North Central and Northeastern United States, west to the Rocky Mountains. Their range in Alaska extends through most of the forested areas, from the Brooks Range through south central and southeast Alaska.
Red squirrels are members of the rodent family, and the species Tamiasciurus hudsonicus has been divided into 25 subspecies. A red squirrel is small, measuring approximately 12 inches (30 cm) in length, with its long, bushy tail accounting for a third of the total length. A large adult may weigh 8.4 ounces (240 g). In the summer, it has a pale red to olive-gray coat with a black line along each side. It is creamy white or buff-colored on its underside. In the winter, it has reddish-brown ear tufts and a bright rusty red strip along the back, while the black stripes along the side fade or disappear. In all seasons, a red squirrel has a white ring around each eye.
Red squirrels are territorial and vigorously defend their territories. A squirrel’s territory can range in size one-half acre to six acres, and each squirrel knows its territory well and may have several nests and food caches within the boundaries of its territory. Red squirrels build their nests in trees. The nests are usually between 10 to 60 ft. (3-18 m) above the ground and are either constructed inside a tree cavity or out of a mass of twigs, leaves, moss, and lichens inside the dense foliage of a branch.[4,5}
Red squirrels mainly eat the seeds of conifer cones. A spruce forest covers the north side of Kodiak Island, and the squirrels living in this forest eat the seeds of spruce cones. Since few spruce trees grow on the rest of the island, though, squirrels in other areas eat and cache alder cones. When collecting cones, a red squirrel cuts green cones from a tree and allows them to fall to the ground. The squirrel then gathers the fallen cones and buries them in one or several caches in its territory. By collecting only green cones, the squirrel knows the seeds are still in the cones.
A squirrel may collect several bushels of cones in a cache, and a cache may be as big as 15 by 18 ft. with a depth of 3 ft. (5 x 6 x 1 m). In addition to one large cache, a squirrel often has several smaller caches in its territory. Besides seeds, red squirrels also eat berries, buds, fungi, insects and bird eggs. They do most of their food collecting during the day but may also be active on moonlit nights. Red squirrels do not hibernate but instead depend on their stored food caches to make it through the winter. In regions with heavy snow, they may dig elaborate snow tunnels to reach their caches.
Red squirrels can climb trees with ease. They run up and down the trunks and along branches and can jump as far as 8 ft. (2.4 m) from one branch to another. On the ground, they walk or run and can run as fast as 14 mph (22.5 km/hr) over short distances.
Red squirrels are solitary animals except during the breeding season, when males leave their territories, and females allow males to enter their territories. A female has a one-day estrous period, and one to ten males may pursue her during that time. The dominant male will approach the female while uttering quiet vocalizations. Copulation is brief but may be repeated several times until the female becomes aggressive. After a gestation of 36 to 40 days, the female gives birth to three to seven young. The young are blind and hairless at birth and weigh only ¼ oz. (7 g). The young develop slowly and do not open their eyes until they are 27 days old. By 30 days of age, they are fully furred and begin to leave the nest. When young red squirrels are 9 to 11 weeks old, they begin to establish their territories.
A red squirrel will emit a long rattling buzz when another squirrel enters its territory, and this call is often accompanied by tail-jerking and foot stamping. Neighboring squirrels may respond with similar calls. A slowly repeated “whuuk” call is an alarm call announcing the approach of a predator. Biologists have noted red squirrels often produce a high-frequency alarm call when they detect an avian predator and a low, barking call when they sense the approach of a land predator. In addition to vocalizations, red squirrels use posturing and chemical signals to communicate.
Red squirrels have a high mortality rate, and only 22% survive to one year of age. Females that survive their first year have a life expectancy of 2.3 years and a maximum lifespan of 8 years. Red squirrels may be preyed upon by hawks, owls, eagles, bobcats, coyotes, weasels, minks, foxes, raccoons, and fishers. In the long term, habitat loss is the biggest threat to red squirrels.[4,5}
Beginning next week, I’ll write a few posts about bald eagles. As always, I appreciate you stopping by to read my blog and would love hearing from you. Please leave a comment!