Part 2

Young from the first litters of the year were above ground by late June and represented the largest segment of the population at that time; for example, only three of 17 individuals collected from June 20 to 27 were adults. Adult females collected on June 20 and July 7 had enlarged mammae but were no longer lactating.

Time of emergence from hibernation in northwestern South Dakota is unknown, but many ground squirrels were active in the last week of March, 1963. A male obtained on March 28 had testes that measured 27 and was in full winter pelage, which is easily distinguished from the shorter, darker pelage of summer.

~Cynomys ludovicianus ludovicianus~ (Ord, 1815)

Black-tailed Prairie Dog

_Specimens examined_ (5).--Sec. 25, R. 3 E, T. 22 N, 2; 1-1/2 mi. W Buffalo, 1; 1/2 mi. W Camp Crook, 3200 ft., 2.

The extensive flatlands of short grasses on relatively deep soils provide ideal habitat for the black-tailed prairie dog in Harding County. Visher (1914:89) mentioned extensive colonies along "flats" of streams and reported one "town" west of the Little Missouri River that covered several sections and another "on the table of the West Short Pine Hills." Recently, emphasis on control of numbers of prairie dogs in the area has reduced many formerly extensive colonies to small, disjunct units. According to Robert Kriege (personal communication, 1968), a "town" of approximately 3000 acres, about five miles east of the Little Missouri River (in R. 2 E, T. 21 N), is the largest remaining in the county. Thirteen other colonies then known to him ranged in approximate size from 25 to 300 acres.

White-colored prairie dogs apparently are not uncommon in some areas of the county and local residents reported to us a number of instances of sighting such individuals. One "town" located 7-1/2 mi. N and 12 mi. W Ladner, in the northwestern corner of the county, contained at least six families of white individuals, congregated together at the edge of the colony, in the spring of 1968. White prairie dogs also were noted by one of our field parties in 1963 in a "town" formerly located 7-1/2 mi. W Buffalo.

~Tamiasciurus hudsonicus dakotensis~ (J. A. Allen, 1894)

Red Squirrel

Visher (1914:88) reported that he obtained a red squirrel in the Long Pine Hills, along the western border of Harding County, in July of 1910 and noted that the species had been reported to him as occurring also in the West Short Pine Hills. Visher's record evidently has been overlooked by subsequent cataloguers (see, for example, Hall and Kelson, 1959: map 257). Insofar as we can ascertain, _T. hudsonicus_ does not now occur on any of the pine-clad buttes and ridges of the county, although the species is present in relatively dense stands of ponderosa pine in the Long Pine Hills of adjacent Carter County, Montana, at a place only a few miles west of the South Dakota border. Probably some individuals stray into the relatively small and sparsely-wooded areas of the Long Pine Hills that extend eastward to the north of Camp Crook.

On the basis of color, specimens we have examined from the Long Pines clearly are assignable to _T. h. dakotensis_ rather than to _T. h. baileyi_, substantiating in part the statement of the distribution of _dakotensis_ published by Miller and Kellogg (1955:263).

~Thomomys talpoides bullatus~ Bailey, 1914

Northern Pocket Gopher

_Specimens examined_ (22).--NE 1/4 sec. 22, R. 1 E, T. 23 N, 1; 7 mi. N, 2-1/2 mi. W Camp Crook, 3300 ft., 3; Camp Crook, 1; 10 mi. S, 5 mi. W Reva, 10; 10 mi. S, 4 mi. W Reva, 4; 2 mi. S, 5 mi. E Harding, 2; Crow Buttes, 1 (USNM).

The northern pocket gopher probably occurs in most areas of northwestern South Dakota where the soil is sufficiently deep for constructing burrows, but we found it commonest in the lower grassy slopes of buttes and in relatively sandy areas along some of the major streams.

A female obtained on June 20 contained two embryos that measured 3. Testes of an adult male trapped on May 18 measured 19 and those of one taken on July 6 measured 9. Juveniles were collected in both May and June.

Bailey (1915:102) referred a specimen from Crow Buttes to _T. t. bullatus_, but Swenk (1941:3), in the original description of _T. t. pierreicolus_, suggested that this same specimen "probably" was referable to the latter because he assumed it came from soils of the Pierre series. However, Baker (1952:8) included the Crow Buttes in the Hell Creek formation and, in any event, one of us (Jones) examined the specimen in question and found it clearly referable to the subspecies _bullatus_. Over and Churchill (1945:32) erroneously assigned pocket gophers from northwestern South Dakota to two different subspecies (_bullatus_ and _clusius_), referring at least one individual from Harding County to _T. t. clusius_.

Fleas, _Dactylopsylla ignota_ (Baker), were found on one individual examined. Molting adults were taken in each month from May through August.

~Perognathus fasciatus fasciatus~ Wied-Neuwied, 1839

Olive-backed Pocket Mouse

_Specimens examined_ (16).--2 mi. N, 5 mi. W Ludlow, 3; 4 mi. S, 7 mi. W Ladner, 9; 10 mi. S, 5 mi. W Reva, 1; 14 mi. S, 4 mi. W Reva, 2; 15 mi. S, 4 mi. W Reva, 1.

This pocket mouse is not uncommon in areas of short grass and sage in Harding County. None of five adult females taken late in June was pregnant or lactating, but three had enlarged mammae indicative of reproductive activity earlier in the spring, to which young of various sizes in our series also attest. Active molt was evident on adults taken on June 19, 26, and 28.

Our specimens are intergrades between _Perognathus fasciatus fasciatus_ and the paler _P. f. olivaceogriseus_. Average external measurements of seven adults (two males and five females) are: total length, 138.0 (130-150); length of tail, 65.3 (59-74); length of hind foot, 17.1 (15-18.5); length of ear (six specimens only), 6.8 (6-7); weight in grams (five specimens only), 12.9 (11.2-14.6). Selected cranial measurements of the two males and two of the females are, respectively, as follows: occipitonasal length, 24.0, 23.2, 23.5, 22.3; interorbital breadth, 4.9, 5.2, 5.0, 5.0; mastoid breadth, 13.0, 13.1, 12.2, 11.9; length of maxillary toothrow, 3.3, 3.3, 3.1, 3.4.

~Perognathus hispidus paradoxus~ Merriam, 1889

Hispid Pocket Mouse

An adult female, not reproductively active, that was trapped in rather sparsely vegetated rangeland to the southwest of Slim Buttes (14 mi. S and 4 mi. W Reva) on July 19, 1961, is the only specimen of the hispid pocket mouse on record from Harding County. Other species of small mammals taken in the same or adjacent traplines were _Perognathus fasciatus_, _Dipodomys ordii_, _Reithrodontomys megalotis_, _Peromyscus maniculatus_, and _Onychomys leucogaster_.

A single individual reported from Wade, Grant Co., North Dakota, by Bailey (1927:123), approximately 100 miles to the northeast, is the only specimen known from a more northerly locality.

~Dipodomys ordii terrosus~ Hoffmester, 1942

Ord's Kangaroo Rat

_Specimens examined_ (13).--NE 1/4 sec. 22, R. 1 E, T. 23 N, 6; 2 mi. N, 5 mi. W Ludlow, 1; 2 mi. S, 11 mi. W Reva, 1; 14 mi. S, 4 mi. W Reva, 4; 15 mi. S, 4 mi. W Reva, 1.

Ord's kangaroo rat is found in sparsely vegetated flatlands throughout Harding County, although it appears to be uncommon except in localized areas of relatively sandy soils. Five of seven specimens taken from June 18 through 24, 1961, were young of the year, as were three of six individuals trapped on May 31, 1968. One adult female (81.1 grams) obtained on May 31 was lactating and had four placental scars, whereas another that weighed 67.2 grams evidenced no recent reproductive activity. An adult male (67.9 grams) taken on May 31 had testes that measured 9; those of a subadult male (46.5 grams) taken on the same date measured only 6.

The two May-taken adult females mentioned above still were completely in winter pelage, but the adult male trapped at the same time was molting. An adult male (57.2 grams) obtained on June 22 had completed molt save for a small patch between the ears and immediately behind the head.

~Castor canadensis missouriensis~ Bailey, 1919

Beaver

_Specimens examined_ (2).--Sec. 22, R. 1 E, T. 20 N, 1; 32 mi. SE Buffalo, 1.

According to local residents, the beaver is common along many of the water courses in the county. One of our two specimens came from a tributary of the Little Missouri River north of Camp Crook and the other was taken from a tributary of the Moreau River in the southeastern part of the county. Robert Kriege of Buffalo reported to us that beaver are not restricted to wooded areas, but frequently inhabit streams and more or less permanent impoundments bordered by grassland. In such places they are said to construct bank dens and eat principally sage and forbs.

Visher (1914:89) reported this species along the Little Missouri River, Boxelder Creek, the forks of Grand River, Bull Creek, and "Devil's Gulch" in the North Cave Hills, and figured (pl. 6) a dam on Rabbit Creek. We have observed evidence of beaver activity along the Little Missouri River southwest of Ladner and along aspen-wooded stream banks in the Short Pine Hills, where in the spring of 1963 abundant sign was found.

~Reithrodontomys megalotis dychei~ J. A. Allen, 1895

Western Harvest Mouse

_Specimens examined_ (27).--NE 1/4 sec. 22, R. 1 E, T. 23 N, 1; 4 mi. S, 7 mi. W Ladner, 3; 2 mi. N, 5 mi. W Ludlow, 7; 1/2 mi. W Reva, 14; 10 mi. S, 5 mi. W Reva, 1; 14 mi. S, 4 mi. W Reva, 1.

The western harvest mouse was taken commonly in stands of tall grasses and forbs, particularly along roadways and fencerows. Occasional individuals were trapped in areas of mixed shrubs and grasses. Four pregnant females taken in late June carried the following number of embryos (crown-rump lengths in parentheses): seven (4), six (5), six (10), five (4). Three adult males taken in the same period had testes that measured 7, 7, and 8, whereas those of two May-taken males measured 12 and 6.

Molt from winter to summer pelage was in progress, from anterior to posterior, on both the dorsum and venter of many May- and June-taken animals. Some individuals had completed molt, or had but a small patch of winter pelage remaining on the rump, as early as the last week in June.

~Reithrodontomys montanus albescens~ Cary, 1903

Plains Harvest Mouse

_Specimens examined_ (3).--2 mi. N, 5 mi. W Ludlow, 2; 1/2 mi. W Reva, 1.

This harvest mouse is uncommon in northwestern South Dakota, although the species probably occurs sparingly in upland grassy habitats throughout Harding County. Our specimens, along with one in the collections of the University of Michigan Museum of Zoology, not previously reported, from 11 mi. S Mandan, Morton Co., North Dakota, represent the northernmost known records of this mouse.

A young adult female, obtained on June 21, carried three embryos that measured 17 and was in summer pelage; an adult male taken on June 27 still was in a worn winter pelage.

At the locality 1/2 mi. W Reva, where traps were set in sparse to relatively lush grassy areas along South Dakota Highway 20, the following small mammals were taken in the same trapline (or adjacent lines) in which one plains harvest mouse was captured: _Spermophilus tridecemlineatus pallidus_, _Reithrodontomys megalotis dychei_, _Peromyscus maniculatus nebrascensis_, _Microtus ochrogaster haydenii_, and _Microtus pennsylvanicus insperatus_.

~Peromyscus leucopus aridulus~ Osgood, 1909

White-footed Mouse

Seven adults of this woodland inhabitant were trapped along shrub-covered banks of the spring-fed stream and small impoundment in Deer Draw of the Slim Buttes (10 mi. S and 5 mi. W Reva). Deciduous trees grew in the bottom of the draw, but the slopes above supported ponderosa pine and juniper. No white-footed mice were found along the generally treeless tributaries of the Moreau and Grand rivers to the east of Slim Buttes nor were these mice found along the Little Missouri River or in likely-looking habitat in the North Cave Hills. The _P. leucopus_ of Deer Draw likely represent, therefore, an isolated segment of a formerly much more broadly distributed population of white-footed mice on the Northern Great Plains in post-Wisconsin times. Other such populations may exist in Slim Buttes and perhaps elsewhere in the county. _Zapus hudsonius_ and _Microtus pennsylvanicus_ were trapped in Deer Draw in association with white-footed mice.

Females collected on June 15 and August 7 were lactating and one taken on June 20 contained six embryos that measured 15. Two males taken on June 2 had testes that measured 12 and 15. These two males and a lactating female taken on June 15 still were in winter pelage, whereas a non-breeding female obtained on June 15 and a male and female (pregnant) trapped on June 20 were in summer pelage or an advanced stage of molt to that pelage. A lactating female taken on August 7 was in summer pelage excepting that what definitely appeared to be new winter pelage was present on the head, cheeks, and below the ears, and molt was evident adjacent to these areas.

Selected average (and extreme) measurements of the seven adults from Deer Draw are: total length, 184.4 (175-199); length of tail, 77.4 (70-88); length of hind foot, 21.1 (20-22); length of ear, 16.7 (16-18); greatest length of skull, 27.8 (27.0-28.4); zygomatic breadth, 14.6 (14.0-14.9); least interorbital width, 4.1 (4.0-4.3); length of maxillary toothrow, 4.2 (4.0-4.4). Three males and two non-pregnant females weighed 34.9, 34.6, 30.5, 32.2, and 31.4 grams, respectively.

~Peromyscus maniculatus nebrascensis~ (Coues, 1877)

Deer Mouse

_Specimens examined_ (214).--19 mi. N, 1 mi. E Camp Crook, 5; 18 mi. N Camp Crook, 2; 2 mi. N, 5 mi. W Ludlow, 58; 4 mi. S, 7 mi. W Ladner, 14; 9 mi. N, 3 mi. W Camp Crook, 3400 ft., 3; 7 mi. N, 2-1/2 mi. W Camp Crook, 3300 ft., 2; NW 1/4 sec. 32, R. 1 E, T. 20 N, 4; 1/2 mi. W Reva, 2; SW 1/4 sec. 30, R. 7 E, T. 18 N, 5; 9 mi. S, 7 mi. W Reva, 3; 10 mi. S, 5 mi. W Reva, 64; 14-15 mi. S, 4 mi. W Reva, 33; 2 mi. S, 5 mi. E Harding, 16; 7 mi. S, 4-1/2 mi. E Harding, 3.

The deer mouse is the most abundant and widespread small mammal in northwestern South Dakota. We took specimens in all terrestrial habitats, although the species was commonest in upland situations such as grassy fencerows, rocky areas, and hillsides supporting shrubs, juniper, or pine.

Adult mice in reproductive condition were taken in each month from May through August, although most of our information is for the months of May and June. In the last half of May, seven pregnant females carried an average of 5.0 (4-6) embryos that ranged in crown-rump length from 2 to 10; three others taken in the same period had six, six, and three recent placental scars, and another was lactating. Twenty-three males collected late in May had testes that measured 5 to 15 (average 10.2). In the last half of June, 19 females contained an average of 4.9 (2-7) embryos that ranged in size from 3 to 30 in crown-rump length, and two more were lactating; seven males obtained in the period June 15-25 had testes that averaged 8.7 (8-10).

Additionally, we took lactating females on July 6, July 7, and August 7, and two individuals with recent placental scars on August 5. Twenty adult males collected in the period July 6 to 18 had testes that averaged 9.3 (6-11.5), whereas those of two taken on August 4 and 5 measured 10 and 12, respectively. Young animals in juvenal pelage were captured in each month, May through August, the earliest being taken on May 20. The first female young of the year that was found carrying embryos was trapped on June 16.

Molt from winter to summer pelage is evident on some specimens taken as early as the latter part of May, but most individuals from that period and from the first part of June still retained winter pelage. By the last half of June, some mice had completed (or nearly so) the seasonal molt, but many retained at least some worn pelage of winter into the first week of July.

Two distinctive maturational pelages are seen in our material--juvenal and post-juvenal or subadult, which generally resembles adult pelage (of season) in texture but is duller of color. Collins (1918) for _P. maniculatus_, Hoffmeister (1951) for _P. truei_, and Brown (1963) for _P. boylii_, among others, have described maturational pelages and sequence of maturational molts similar to those observed in our specimens.

Deer mice from Harding County clearly are referable to _P. m. nebrascensis_ (rather than to the smaller and paler _P. m. luteus_, which occurs to the east and southeast), even though adults average somewhat paler than adults of typical populations of that subspecies. A tick of the _Ixodes ochotonae-angustus_ complex was obtained from one specimen.

~Onychomys leucogaster missouriensis~ (Audubon and Bachman, 1851)

Northern Grasshopper Mouse

_Specimens examined_ (4).--NE 1/4 sec. 22, R. 1 E, T. 22 N, 2; 2 mi. N, 5 mi. W Ludlow, 1; 14 mi. S, 4 mi. W Reva, 1.

We found the grasshopper mouse uncommon in Harding County. All four of the mice listed as examined were trapped in areas supporting sage and short grasses, with relatively little ground cover.

Three of our four specimens are immature--two males collected on May 31 (testes 10, 12) and a female taken on June 25. An adult male trapped on June 18 was in winter pelage, but molt was underway on the crown, between the ears, and over the upper back and shoulders.

~Neotoma cinerea rupicola~ J. A. Allen, 1894

Bushy-tailed Wood Rat

_Specimens examined_ (8).--2 mi. N, 5 mi. W Ludlow, 5; 12 mi. N Buffalo, 1 (USNM); 7 mi. N, 2-1/2 mi. W Camp Crook, 3300 ft., 1; 2 mi. S, 5 mi. E Harding, 1.

This woodrat is relatively uncommon, yet widely distributed, in northwestern South Dakota. The species probably occurs throughout the rocky areas in the hills and buttes of Harding County, and also frequents abandoned or little-used buildings and feed stations for livestock. All of our specimens were trapped in rocky habitats, but in many such places we trapped unsuccessfully for _Neotoma cinerea_, even though some sign of its presence frequently was evident. Five of our seven specimens (all taken late in June or early in July) are young of the year in grayish pelage. An adult male trapped on July 14 had testes that measured 14.

Over and Churchill (1945:40) mentioned a specimen, which they referred to the subspecies _N. c. cinerea_, that "probably came from the Slim Butte area of Harding County." Visher (1914:89) recorded the species as "plentiful and general" in the county.

~Microtus ochrogaster haydenii~ (Baird, 1858)

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.

The coyote population in Harding County and adjacent areas is low owing to an active predator control program that is supported by local ranchers and by state and federal agencies. Our field parties neither saw nor heard coyotes, although tracks were found at one or two places in March of 1963. According to Robert Kriege (personal communication), the few coyotes that do reside in the area find refuge in the most rugged parts of the hills and buttes. Visher (1914:90) reported that this carnivore was "generally considered as abundant." Our specimens all are skulls of individuals killed by a federal trapper in the winter of 1961-62.

~Canis lupus nubilus~ Say, 1823

Gray Wolf