Black-Tailed Pra1r1e Dog . Locations of black-tailed prairie dog towns 

 identified in the study area are shown in map 4. These include towns located 

 during this study as well as those reported by the U.S. D.I. Bureau of Land 

 Management, the Montana Department of Livestock, and McEneaney and Jensen (1974). 

 The greatest densities were found along the southern end of Big Dry Arm and along 

 Big Dry Creek while relatively few towns were located in the uplands of central 

 McCone County. One prairie dog town was identified on the proposed mine study 

 area (figure 25). This town contained 364 active burrows over an area of approx- 

 imately 6.2 km2 (2.4 mi^). While a badger burrow was found near the colony, 

 there was no evidence for use of the colony by burrowing owls, mountain plovers 

 or black-footed ferrets. The colony was grazed frequently by a herd of about 40 

 horses and up to 37 pronghorn antelope. Local residents are aware of the loca- 

 tion of the colony, and an unknown proportion of prairie dog mortality is 

 attributable to their shooting. 



Mule Deer . Data were recorded for 3486 mule deer observations representing 

 791 groups during the study period (table 19). Seasonal changes in group size are 

 shown in Figure 26. Groups were largest in winter and early spring, and averaged 

 seven deer during December and January. Average group size decreased from seven 

 in March to three in May as winter herds disbanded during the spring green-up; 

 average group size was lowest during the three summer months, and increased grad- 

 ually throughout the fall months to the winter maximum. The average yearlong 

 group size was four, and the largest group observed was a herd of 26 at the Waller 

 Ranch. 



The distribution of mule deer observations by season is shown in Maps 6-10. 

 During the winter of 1976-1977, aerial flights were completed only over the mine 

 study area; mule deer were occasionally observed within the proposed mining area, 

 but did not appear consistently or in large numbers (map 6). Many sightings were 

 made along Highway 24 west of the proposed mining area during this season, but 

 use is exaggerated by the ease of vehicle observations here. One group of 24 

 mule deer wintered at the Waller Ranch, where they were fed daily. During spring 

 cf 1977, three aerial surveys of the mine study area and one of the reconnaissance 

 area revealed mule deer to be generally distributed over the entire reconnaissance 

 area, with relatively lower densities in the eastern half (map 7). Although biased 

 by area accessibility via vehicles, spring ground observations indicated high den- 

 sities of mule deer along Highway 24 between Timber Creek and the South Fork of 

 Rock Creek in an area of badlands and coulees. Mule deer were observed more fre- 

 quently on the proposed mining area in spring than during the previous winter, 

 and were usually associated with the coulee breaks area in the northern half of 

 th'j proposed mining area. 



During the summer of 1977, limited aerial observations of mule deer did 

 not indicate any distribution trends on the reconnaissance area; summer ground 

 observations again indicated greater densities of mule deer in the concentration 

 areas used during the previous season (map 8). In summer, mule deer were ob- 

 served frequently in the vicinity of the proposed mining area, especially in or 

 near coulees in the northern half of the proposed mining area. Fall, 1977 aerial 

 observations indicated that mule deer were generally distributed throughout the 

 reconnaissance area with greater densities occurring in the southwest quarter 

 of this area (map 9). During fall, mule deer were observed frequently in an 

 area of grassy hills and coulees in the northwest quarter of the proposed mining 

 area, where use was more intense than noted in previous seasons. Fall distri- 

 bution over the remainder of the proposed mining area and vicinity appeared to 



91 



