Phenacomys
intermedius
(Heather Vole)
Description:
This little-known small mammals
is grayish-brown above with a light gray to silvery color underneath. They have
a fairly short, bicolored tail. They are hard to distinguish from the montane
and meadow voles. Total length is 4.6 to 6.2 inches (115-155 mm), tail length
is 0.9 to 1.3 inches (22-33 mm), and it weighs 0.9 to 1.4 ounces (25-40 g).
Range:
From Labrador, west across northern Canada
to Yukon Territory, and south to Sierra Nevada and through Rocky Mountains to
northern New Mexico.
Habitat:
Found, from sea level to above treeline,
in open coniferous
forests with heath or
shrub understory, in shrubby areas on forest edges, in mossy meadows in forests,
and in alpine tundra with cover. Has been trapped
in burned and logged areas of northern Idaho.
Diet:
In
winter, feeds on bark and buds of shrubs and heaths. In summer, feeds primarily
on green vegetation, berries, and seeds.
Ecology:
Relatively little is known about the
heather vole, but it is thought to be evolutionarily ancestral to other voles.
They do not develop well-defined runways as other voles do, except in the immediate
vicinity of their nests. In winter, this non-hibernator builds spherical nests
of grasses and lichens under snowcover, and it lives in shallow burrows under
logs, roots, or rocks during the summer. Unlike other voles, this species stores
some food in winter and summer. It appears to be solitary in summer, except
during the breeding season. Family groups may occupy communal nests in winter.
population density estimates range from 0.5-10
per 2.5 acres (1 ha) in different habitats in different areas. Preliminary results
of a northern Idaho study indicated that this species is uncommon in old-growth
coniferous forest stands but more abundant in second-growth and clearcut areas.
Reproduction:
Gestation lasts 19-24 days. Young
are born mid-June to early September (season may possibly be more restricted
at high elevations). In general, young-of-year females produce 3-4 young (average);
older females may produce 2 litters of 4-6 young/litter.
Conservation:
 Status: |
 Unprotected
nongame species |
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Global Rank: |
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State Rank: |
S4 |
Important State References:
Groves, C.R. 1994. A preliminary report:
effects of timber harvest on small mammals and amphibians in old-growth coniferous
forests on the Priest Lake Ranger District, Idaho Panhandle National Forests.
Idaho Dept. Fish & Game, Boise. 18pp.