Microtus townsendii (Bachman)
Townsend meadow mouse
Description.—The Townsend meadow mouse is a large-bodied, long-furred mouse with a tail of moderate length. Head and body measure about 8 inches, the tail about 2-1/2 inches. The legs are short and the ears scarcely project through the fur on the head. In summer the color is dark reddish-brown. The winter color is dark brownish-black. Underparts are paler, more grayish brown, than are the upper parts. The tail is sparsely haired.
Townsend meadow mice occur west of the Cascade Mountains in California, Washington, Oregon, British Columbia, and on some British Columbian and Washington islands. The habitats of the two races of the Townsend meadow mice found in Washington are wholly in the humid subdivision of the Transition Life-zone but vary somewhat in nature. The race townsendii lives in marshes or damp meadows, under cover of deep, rank vegetation. These mice avoid forested areas or dry brush, but sometimes occur in dry grass when it is deep enough to conceal them from enemies. The race pugeti has been recorded from meadows, salt marshes, driftwood strewn on sea-beaches, areas of sparse, dry grass, and piles of rocks.
Townsend meadow mice are as diurnal as they are nocturnal; specimens have been trapped at almost all hours of the day and night. Their ordinary method of traveling is a slow run. When startled they make a dash for the nearest cover, into which they dive headlong. They make considerable noise while moving about and often may be heard from several feet away. Captives in the laboratory seemed rather dull and stupid as compared with other meadow mice.
Fig. 115. Runways of Townsend meadow mice (Microtus townsendii) worn to grooves in the damp soil at Seattle; May 18, 1938; dense cover of cattails has been burned off (W. W. [Dalquest] photo).
In the fall, winter, and early spring the Townsend meadow mice keep to their runways. These runways are used by successive generations of mice, and often are worn into ditches several inches deep. In the late spring and summer, when the grass and other vegetation in their habitat is tall and rank, offering complete concealment, the runways are abandoned and cuttings of rejected food are found scattered over the surface of the ground.
The food of the Townsend meadow mice includes the succulent leaves and stems of many grasses and annuals. Near Seattle the staple summer food is the velvet grass (Holcus lanatus), although many other plants, including the horsetail (Equisetum arvense), are eaten. In winter the common cattail is eaten. [Couch] (1925: 200) found caches of the roots of mint (Mentha canadensis) stored by this species. As much as 14 quarts was found in a single cache.