Part 7

Prairie Vole

Specimens examined (40).--NE 1/4 sec. 22, R. 1 E, T. 23 N, 1; NW 1/4 sec. 15, R. 5 E, T. 22 N, 1; 2 mi. N, 5 mi. W Ludlow, 4; 4 mi. S, 7 mi. W Ladner, 19; 1/2 mi. W Reva, 2; SW 1/4 sec. 30, R. 7 E, T. 18 N, 3; 10 mi. S, 5 mi. W Reva, 10.

The prairie vole is the most abundant of the three microtines that are known from Harding County. Our specimens came primarily from areas of relatively dense grasses, such as those found in stream bottoms and along fencerows. At two places, along a fencerow 1/2 mi. W Reva and in Deer Draw, 10 mi. S and 5 mi. W Reva, Microtus ochrogaster and the meadow vole, M. pennsylvanicus, were trapped together.

Nine females taken late in May and in June carried an average of 4.4 (3-6) embryos that averaged 14.8 (4-25) in crown-rump length. Each of two lactating females taken in late May had six placental scars. Testes of seven adult males taken in May and June averaged 13.1 (12-16) in length.

~Microtus pennsylvanicus insperatus~ (J. A. Allen, 1894)

Meadow Vole

Specimens examined (14).--1/2 mi. W Reva, 1; 10 mi. S, 5 mi. W Reva, 12; 7 mi. S, 4-1/2 mi. E Harding, 1.

This vole evidently is limited in Harding County to habitats of dense grass and forbs adjacent to water. We failed to trap the species in some areas that appeared to be suitable for occupancy.

Two females, collected on May 15 and June 2, contained three and six embryos, respectively, that measured 15. One female with five placental scars (May 15) and two with six (May 16, June 2) also were trapped, and a lactating female was captured on June 20. Testes of two adult males taken in spring (May 18 and June 2) measured 15, and those of one weighing 45.6 grams that was taken early in June measured 17.

~Ondatra zibethicus cinnamominus~ (Hollister, 1910)

Muskrat

The muskrat is common in Harding County. Half a century ago Visher (1914:89) noted that it was "Fairly plentiful along the streams having deep permanent 'holes'."

Seven adults, all in winter pelage, were taken late in March from a pond near the west side of Slim Buttes (5 mi. S and 14 mi. E Buffalo). Testes of three adult males measured 17, 19, and 22; of three females, none evidenced reproductive activity.

~Mus musculus~ Linnaeus, 1758

House Mouse

The house mouse evidently is uncommon in rural environments in northwestern South Dakota. One subadult female was trapped along a "weedy" fencerow, 2 mi. N and 5 mi. W Ludlow.

~Zapus hudsonius campestris~ Preble, 1899

Meadow Jumping Mouse

Eleven specimens of this jumping mouse were taken from a relict population restricted to a shrub-grass habitat adjacent to a small spring-fed stream and impoundment in Deer Draw (10 mi. S and 5 mi. W Reva). Similar isolated populations may be present in the few other suitable mesic habitats in Harding County, but we have trapped extensively, yet unsuccessfully, for Zapus in such situations; specimens are known, however, from the Long Pine Hills and from along the Little Missouri River in adjacent Carter County, Montana. It is of interest that a relict population of Peromyscus leucopus also occurs in Deer Draw.

The testes of two adult males obtained on June 3 measured 7, whereas those of one taken on May 16 measured 16. Seven embryos (measuring 8 in crown-rump length) were carried by a molting female trapped on June 16. Our specimens of Zapus, currently under study by Paul B. Robertson, appear to be intergrades between the subspecies campestris and intermedius, but resemble the former more closely than the latter.

~Erethizon dorsatum bruneri~ Swenk, 1916

Porcupine

Specimens examined (11).--NW 1/4 sec. 15, R. 5 E, T. 22 N, 1; 2 mi. N, 5 mi. W Ludlow, 3; 4 mi. S, 7 mi. W Ladner, 1; 10 mi. S, 4 mi. W Reva, 1; 10 mi. S, 5 mi. W Reva, 4; 2 mi. S, 5 mi. E Harding, 1.

The porcupine is a common resident of the pine-clad buttes of Harding County and individuals were occasionally encountered some distance from pines. We noted porcupines almost nightly in June of 1961 along the road that parallels the Slim Buttes to the east, and found a number that had been struck by automobiles along this and other roadways in, or adjacent to, wooded areas. Visher (1914:90) earlier reported Erethizon from Harding County.

Order Carnivora

~Canis latrans latrans~ Say, 1823

Coyote

Specimens examined (8).--North Cave Hills, 1; N of Slim Buttes, 1; N end Slim Buttes, 1; 6 mi. N, 4 mi. W Camp Crook, 2; W of East Short Pine Hills, 1; E of Short Pine Hills, 1; Sheep Mountain, 1.