terrain, hillsides, and flat areas provided 55% of the observations for which 

 topography was recorded (figure 34). Pronghorn antelope appeared to use coulees 

 and creek bottoms more frequently than during spring, possibly in response to 

 desiccation of grassland habitats. 



In fall of 1977, pronghorn antelope appeared in a variety of habitat types; 

 however, the majority were observed on grasslands (48%) and cultivated fields 

 (31%) (figure 33). Habitat use did not appear to vary greatly from September 

 to November. Feeding pronghorn antelope were most frequently observed on grass- 

 lands (43%). Stubble, fallow fields, and big sagebrush habitat also appeared 

 to be important during fall. Rolling terrain accounted to the majority of both 

 total and feeding observations during the fall of 1977 (figure 34); flat areas 

 and hillsides received moderate use. 



Over 90% of all pronghorn antelope observed were located on slopes of less 

 than 15% (table 26). No major seasonal differences were apparent. Pronghorn 

 antelope on the Birney-Decker area of southeastern Montana were also observed 

 mainly on gently sloping terrain (Knapp 1977). 



The majority (75%) of all pronghorn antelope were observed between 5:00 

 A.M. and 1:00 P.M. During spring and summer 70% and 68% respectively, were 

 seen from 5:00 A.M. to 9:00 A.M. Pronghorn antelope were observed more fre- 

 quently during afternoon hours in the fall, with nearly half seen between 9:00 

 A.M. and 1:00 P.M. Nearly half of all pronghorn antelope were seen between 1:00 

 P.M. and 5:00 P.M. during the winter. 



Seasonal food habits have been well documented in studies of pronghorn 

 antelope east of the Rocky Mountains in Montana (Knapp 1977, Becker 1972, 

 Freeman 1971, Campbell 1979, Bayless 1969, Wentland 1968, Cole and Wilkins 

 1958, Cole 1956, Couey 1945). Food habits of pronghorn antelope in McCone 

 County should not differ greatly from the findings of these studies. Prong- _ 

 horn antelope on the study area were observed feeding on silver sagebrush, big 

 sagebrush, horizontal juniper, and yucca during the winter. Concurrent with 

 the spring green-up, antelope moved into grasslands and cultivated lands, pro- 

 bably feeding on forbs and sprouting crops. Use of cultivated fields during 

 fall suggests use of waste and sprouting grain in addition to use of range 

 browse. 



Seasonal sex and age ratios calculated from classified observations of 

 antelope are shown in table 24 (see also Appendix M). Reduced observability 

 of fawns during spring and early summer and the low percentage of classified 

 observations during winter dictated the use of fall data for estimating the 

 most realistic age ratios. During the fall, ratios of 57 fawns:100 adults and 

 81 fawns: 100 females were obtained. A production estimate of 80 fawns per 100 

 females is rated "good" by Fish and Game Department standards. Comparison with 

 census data compiled by the Fish and Game Department for several years in Mc- 

 Cone County indicate these ratios may be low (table 25); Aerial census data 

 from 1960 through 1976 gave ratios of 90-100 fawns per 100 females for hunting 

 unit 650. Most studies of pronghorn antelope productivity use summer census 

 data, and using the 452 classified observations made during August, 1977, a 

 ratio of 90 fawns:100 females is obtained. 



Sex ratios calculated from winter and spring data may be inaccurate due to 

 low numbers of classified observations during winter and the reduced observ- 



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