during all seasons except winter when they appeared to move to lower elevation 

 habitats with less snow cover. 



According to Brown (1967, 1971), tlie most secure habitat for sharp-tailed 

 grouse is upland mixed prairie rangeland, intermixed with trees and shrubs, 

 where despite heavy grazing or cultivation, residual herbage (chiefly grasses) 

 remains from fall to spring. Especially important to sharp-tailed grouse pop- 

 ulations are the areas where grassland, trees, and shrubs border one another 

 (Yde, 1977). This was generally found to be the case in the study area. 

 Seasonal use of various habitat categories is shown in figure 5. (A more detailed 

 account of habitat use is given in Appendix K.) Grassland and sagebrush were the 

 most important habitat categories yearlong, and together accounted for over 50% 

 of all recorded observations. The high observability of grouse gathering grit 

 and feeding on road and highway embankments probably resulted in over-estimation 

 of the importance of these roadside habitats, which accounted for over 12% of 

 all observations. Low coulee shrub, which provided both food and shelter from 

 the weather, and snowberry-rose were important habitats during the relatively 

 mild winter of 1975-77. Grouse also apparently sought spilled grain in farm 

 yar<ls and picked up grit on roads where they were easily visible during the 

 vehicle routes. A majority (60%) of the grouse observed during spring were en- 

 gaged in courtship activities, and leks were typically located in flat or gently 

 rolling grasslands either on benches or floodplains, usually with scattered sil- 

 ver or big sagebrush present. 



During summer and fall, a shift to shrubland habitats, especially sage- 

 brush and tall coulee shrub, was apparent, as birds sought shade and cover. This 

 shift was also reported by Yde (1977) for a study in Phillips County, Montana. 

 While sample size was small during the severe winter of 1977-78, trees and wooded 

 farmsteads appeared more important than low shrubs, which were largely covered 

 with snow. The birds sought food and shelter in the proximity of farmyards. 

 Topography use was recorded for only 68% of the observations, and no clear 

 trends are apparent from the data. Food habits of sharp-tailed grouse in and 

 near the study area are reported by Trueblood (1977). 



Figure 6 shows monthly sample abundances of sharp-tailed grouse along the 

 five roadside wildlife survey routes. Sample abundances peaked in April and May 

 as birds gathered on dancing grounds where they were easily detected. A minor 

 peak in October corresponds to an autumn return to these grounds, related to day 

 length. Most of the observations were made along the Prairie Elk route, which 

 passed near several leks and appeared to provide 'ijery suitable habitat for sharp- 

 tailed grouse. A substantial number of observations were made along the Missouri 

 River route, which also traversed several leks. Few grouse were seen along the 

 other routes. The Dreyer Ranch route passes near a dancing ground near its 

 southern end and it is likely that the May sample abundance along this route 

 would have been higher had the route been run from south to north that month. 



Twelve broods were observed during the study. Broods averaged five birds and 

 ranged from one to eleven birds which indicates substantially smaller broods than 

 reported by Yde (1977) for Phillips County. Annual F & G wing collections in 

 McCone County from 1970 through 1975 revealed an average juvenile adult ratio 

 of 2.5 (Trueblood 1976). Population numbers of sharp-tailed grouse appear to 

 fluctuate between years of high and low production, probably as a result of 



67 



