Fig. 110. Distribution of the heather vole in Washington. A. Phenacomys intermedius oramontis. B. Phenacomys intermedius intermedius.
The winter nests of Phenacomys intermedius are placed on the surface of the ground and in the season when occupied are deeply buried under the snow. They are spherical or oval in shape, six to eight inches in diameter and with a side entrance. One examined by [Shaw] was "formed of white heather twigs, the interstices being filled with leaves of huckleberry." It was "lined with finely shredded grass." All those examined by me were composed of grass and lichens.
The principal foods of the heather vole seem to be white heather (Cassiope mertensiana) and huckleberry (Vaccinium). Red heather (Phyllodoce empetriformis) is not eaten. [Shaw] also lists beargrass (Xerophyllum tenax) and lousewort (Pedicularis) as eaten.
A burrow excavated and figured by [Shaw], was slightly more than a yard long and contained four young in a nest situated but a few inches from one of the three entrances. The nest was made of grass and moss. A female taken at Tye, King County, contained 4 embryos on May 28, 1939. One taken at Pass Creek Pass, Pend Oreille County, contained 3 small embryos on June 14, 1938.
Phenacomys intermedius intermedius [Merriam]
Phenacomys intermedius [Merriam], N. Amer. Fauna, 2:32, October 30, 1889.
Phenacomys intermedius intermedius [Howell], N. Amer. Fauna, 48:15, October 12, 1926.