Southern Red-backed Vole(Clethrionomys gapperi)
from: Saunders, D. A. 1988. Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp.
Description: This slender vole has relatively prominent, rounded ears, and long coarse fur, buffy to yellowish gray on the sides and silvery gray on the underparts of the body. The bicolored (dark brown above and gray below), sparsely haired, 35-45 mm (1.4-1.8 in) tail, and a bright reddish chestnut band along the back from the forehead to the base of the tail separate this species from other small mammals of the Adirondacks. Adults vary in total length from 136-150 mm (5.2-5.9 in), and weigh about 27 g (1.0 oz).
Range and Habitat: The range is the forested regions of Canada, the northern U.S. and the Northeast; to southwestern New Mexico and Arizona in the Rockies; and to northern Georgia in the Appalachians. The southern red-backed vole occurs in all terrestrial habitats of the Adirondacks including alpine tundra, bogs, and swamp edges, and at all elevations. However, it prefers moist forests, especially the mixed coniferous-deciduous, with an abundant supply of logs, stumps, roots, rocks, and twigs which provide shelter, food, and moisture or humidity. Population levels, precipitation, and the relative abundance of other small mammals such as meadow vole influence local distribution in marginal habitat.
Red-backed voles build nest 7.6-10.2 cm (3-4 in) in diameter from plant materials such as sphagnum and dried leaves under logs and stumps; in the abandoned nests and dens of other mammals; but occasionally in trees or underground.
Food and Feeding Behavior: The red-backed vole is primarily an herbivore, although it eats small invertebrates infrequently. A diet of fruit, succulent vegetation, and especially fungi that it excavates from the forest floor indicates that dependence of this species on water, which is acquired from both food, and by drinking. In autumn, voles cache seeds, nuts, and roots near their nests for winter consumption, but the bark of deciduous trees and shrubs may be an important winter food when these are unavailable.
Activity and Movement: Although capable of jumping 15-20 cm (6-8 in) over obstacles, a red-backed vole usually travels by hoping, walking, or running. It swims and climbs well, and may forage in trees 2-3 m (7-10 ft) above the ground. During the winter, this vole is active during daylight hours under snow cover; during the rest of the year, the red-backed vole is primarily active at twilight or night.
Reproduction: Females bear 2-3 litters from late winter to late autumn, and may mate within 12 hours after giving birth. The average litter size is 4 or 5, but can vary from 2-8. The gestation period is 17-19 days. The young are weaned by 17-21 days of age. Age at sexual maturity is 60 days for females, somewhat longer for males. Few red-backed voles live 20 months, the potential life span. Most survive less than one year.
Predators: Merriam state that "the flesh of the red-backed mouse is tender and well flavored." (p 272) While few of us would test his judgment, many predators consume this rodent. A few of the Adirondack representatives are coyotes, short-tailed shrews, fishers, foxes, and broad-winged hawks.
- Social System - The red-backed vole is promiscuous, and other than temporary female-young groups, solitary. Adults either avoid others of the same sex or react aggressively. Home ranges overlap, there size usually 01.-1.4 ha (0.35-3.56 acres), but sometimes much larger. Season, population density, and available food are important determinants of home range size. Local populations fluctuate, peaking at intervals of 3-6 years, and may build to densities of 65 per ha (26 per acre).
- Communication - The behavioral interactions of this vole in the wild are not well known. Vocal, visual, tactile, and chemical signals are likely. Adults have hip glands which probably play a role in chemical communication. Adults tooth-rattle, squeal, chatter, and chur when disturbed.
Fisher, R.L. 1968. An ecological study of the red-backed vole, Clethrionomys gapperi gapperi (Vigors) in central New York. Unpubl. Ph. D. Disset., Cornell Univ., Ithaca, NY. 79pp.
Getz, L.L. and V. Ginzberg. 1968. Arboreal behavior of the red-backed vole, Clethrionomys gapperi. Animal Behavior, 16:418-424.
Hatt, R. T. 1930. The biology of the voles of New York. Roosevelt Wildlife Bulletin, 5(4):513-623.
Kirkland, G.L. Jr., and R.J. Griffin. 1974. Micro-distribution of small mammals of coniferous-deciduous forest ecotones in northern New York. Journal of Mammalogy, 55:417-427.
Martell, A.M. 1981. Food habits of southern red-backed voles (Clethrionomys gapperi) in northern Ontario. Canadian Field Naturalist, 95:325-328.
Merritt, J.F. 1981. Clethrionomys gapperi. Mammalian Species, 146:1-9.
Patric, E.F. 1962. Reproductive characteristics of red-backed mouse during years of differing population densities. Journal of Mammalogy, 43:200-205.
Steblein, P.F. 1984. Niche-habitat relations of red-backed vole, Clethrionomys gapperi (Vigors) from New York and Pennsylvania. Unpubl. M.S. Thesis, Shippensburg Univ., Shippensburg, PA. 84pp.