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Red Squirrel

Red Squirrel
(Tamiasciurus hudsonicus)

from: Saunders, D. A. 1988. Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp.

Order: Rodentia

Family: Sciuridae

Description: This, the Adjidaumo of Longfellow’s celebrated poem Hiawatha, is the voice of the Adirondack’s brooding forests. The red squirrel’s appearance varies seasonally. The paler, reddish to olive gray coat of summer includes a black line along each side, and creamy white or buffy underparts. In the winter, reddish brown ear tufts and a bright rusty red stripe along the back develop while the black lines along the sides are usually faint or absent, and the underparts become silvery gray or white. A buffy or white eye-ring is present in all seasons. This common tree squirrel of the Adirondacks is about half the size of a gray squirrel, and is stouter, longer, and lacks the dorsal stripes of the eastern chipmunk. The red squirrel is about 30 cm (12 in) long, the tail accounting for nearly a third of the total length. Large adults weigh 240 g (8.4 oz).

Range and Habitat: The range of the red squirrel is from the tree line of North America south into the northern U.S., the Northeast, and continuing in the Rocky and Appalachian Mountains. Although primarily an inhabitant of coniferous and mixed forests, it may also reside in deciduous forests, especially the northern hardwoods. In the Adirondacks, the red squirrel is associated with the coniferous and mixed forests at all elevations.

Within these habitats, red squirrels build nests 3-18 m (10-60 ft) above the ground inside a natural tree cavity, abandoned woodpecker nest, or on a branch. Exposed nests are usually near the trunk on a large branch, occasionally in a witch’s-broom.

Five week old red squirrel

The nest is 20-50 cm (10-20 in) in diameter, and made of a coarse outer layer of bark or litter from the forest floor, and an inner layer of finely shredded bark, often from yellow birch or white cedar. A single entrance, opposite the side nearest the trunk of exposed nests, leads to the inner chamber. Red squirrels may also build nests in an underground chamber which they excavate. These chambers are approximately 23 cm (9 in) long, 10-13 cm (4-5 in) in diameter, and 30 cm (12 in) beneath the surface of the ground. Buildings, logs, stumps, log piles, bird houses, and rock walls are other locations.

Food and Feeding Behavior: The seeds of conifer cones form the mainstay of diet of this rodent. To get these cones, the red squirrel clambers about the branches of balsam fir, larch, white cedar, pines, and spruces, cutting green cones. A dozen or more may fall to the ground before the squirrel descends to retrieve and bury the cones in one or several chambers in its territory. By cutting only green cones, the red squirrel ensures that the seeds are still present. Middens mark the presence of the red squirrel. The term midden in the case of this species refers to both food cache, and to the debris that accumulates over months and even years from stripping cones on a nearby log, branch, or stump.

Other important foods include the buds, inner bark, sap, nuts and seeds of deciduous trees and shrubs. Fungi, even some species of the toxic genus Amonita, and fleshy fruits may form a large part of the summer diet with the surplus carried aloft to dry among twigs or wedged between branches. Red squirrels also consume invertebrates such as insects, and some vertebrates, for example, small mammals birds, and birds’ eggs.

Remnants from a red squirrel meal

Remnants from a red squirrel meal

Juvenile red squirrel peeking from

Juvenile red squirrel peeking from
it's underground den

Activity and Movement: The red squirrel is diurnal and arboreal, its activities in the trees often unnoticed because of the dense foliage. During the warmest days of mid-summer, activity peaks at twilight. Midday activity is typical of cold winter days when red squirrels leave the protection of their nests to visit food stores, sometimes digging elaborate snow tunnels to reach there stockpiles.

Red squirrels navigate trees with ease, running up and down trunks, or along branches, bounding up to 2.4 m (8 ft) through the air from one branch to another to reach different trees, occasionally falling to the ground unscathed. On the ground, they walk or run, and when alarmed, they may attain speeds of 22.5 km/hr (14 mph) for short distances.

Reproduction: The courtship which precedes mating between a pair of red squirrels is brief and relatively unritualized. One to 10 males may pursue a female during her one day estrous period, the dominant male eventually approaching the female while giving quiet vocalizations, and then mounting her. Copulation is brief, but may recur several times before the female becomes aggressive. Some females may mate again with different males. After a gestation period of 36-40 days, the female bears her young in a nest of shredded bark and leaves. A typical litter contains 3-5 young, but can vary from 1-8. Blind, naked, and pink at birth, the young develop slowly, their eyes not opening until 27 days of age. By day 30, they are fully furred, and they begin to venture from the nest. They are weaned soon after. By 9-11 weeks of age, they establish their own territories.

Some females produce litters in both April and August, but others produce just one litter annually during one of these periods. Sexual maturation of the young occurs the winter following their birth. Red squirrels may live 10 years, although 3-5 years is the average life span for adults.

Predators: Raccoons, foxes, bobcats, coyotes, weasels, minks, fishers, hawks, owls, and martens are predators of the red squirrel.

Social Behavior:

  • Social System - Pugnacious, fearless, timid, saucy, curious, and loquacious are terms early naturalists used to characterize the red squirrel. While more descriptive terms are used today, these older words do capture the personality of the red squirrel. The red squirrel is sedentary, solitary, and promiscuous, and defends a territory of 0.4-3.2 ha (1-8 acres). During breeding season, males wander from their territories. While in estrous, a female permits their encroachment on her territory.
  • Communication - A resident red squirrel gives a long, rattling buzz, the notes slowing and fading, when another red squirrel enters its territory. At the highest intensity, tail-jerking and foot stamping accompany the call. Neighboring red squirrels may respond with similar calls, producing a chorus. This call functions to advertise an occupied territory and to increase the distance between individuals. A slowly repeated “whuuk” occurs as an alarm call. Motor patterns, posturing, and chemical signals convey information among red squirrels, but are not as specialized as vocalizations, a consequence of the lifestyle amidst concealing conifer.

Additional References

Fitzwater, W.D., Jr. 1941. The red squirrel: territorialism, activity, census methods. M.S. Thesis, SUNY CESF, Syracuse NY. 117pp.

Hatt, R.T. 1929 The red squirrel: its life history and habits, with special reference to the Adirondacks of New York and the Harvard forest. Syracuse Univ. Press, Syracuse, NY. 146pp.

Layne, J.N. 1954. The biology of the red squirrel, Tamias sciurus hudsonicus loquax (Bangs), in central New York. Ecological Monographs, 24:227-267.

Robbins, C.T.1971. A study of red squirrel activity. M.S Thesis, SUNY CESF, Syracuse, NY. 117pp.


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