Eastern Segment 



Mule deer are the most abundant and widely distributed big 

 game animal on the study area. Confirming data were obtained by 

 numerous observations made during the entire study (Constan 1976, 



1977, 1978 and Appendix Table 2). Mule deer are found associated 

 with all vegetation types present in the study area; however, 

 they appear to prefer the Missouri Breaks scrub-pine vegetation 

 type. Generally, mule deer in the study area are nonmigratory , 

 as they usually make only small seasonal movements. Mule deer 



in the breaks habitat tend to disperse in the spring and summer 

 and concentrate at the heads of the drainages in the winter. 

 Deer in the nonbreaks areas also disperse in the spring and sum- 

 mer and then concentrate on rough sagebrush-grasslands or steep 

 wind-swept hillsides during winter. 



Emphasis during the study was placed upon delineating mule 

 deer winter ranges. Winter ranges were identified during the 

 1975-76 and 76-77 winters and plotted. The winters of 1977-78 

 and 78-79 were extremely severe, so they provided an opportunity 

 to identify areas where mule deer winter under severe weather 

 conditions. All winter ranges located, under average and severe 

 winter conditions, were plotted and are presented in Figure 11. 



An intensive winter mule deer survey, by helicopter, was 

 made of the Birch Creek drainage in Hunting District 680, 

 Figure 12. Observations of 948 mule deer were obtained during 

 the flights on February 19 and 20, 1979. The approximately 

 222 square miles covered by the survey had a density of 4.3 

 mule deer per square mile. This breaks habitat density of 4.3 

 is higher than the densities of 3.0 and 3.5 that were found in 

 similar breaks habitat on the south side of the Missouri River 

 during the winters of 1976-77 and 1977-78, respectively. 



Winter classification of 1,157 mule deer was made during 

 the report period (Table 6) . The 1978-79 winter fawn/adult 

 ratios showed significant increases over the 1977-78 ratios and 

 were the highest obtained in Hunting Districts 410, 426 and 680 

 during the 4 years of this study. Overall, it appears that 

 mule deer reproduction and/or survival is on the increase in 

 the Missouri River Breaks. 



Hunter harvest figures are presented in Table 7. The 1978 

 harvest in Hunting Districts 410 and 6 80 (see Appendix Figure 1) 

 decreased from the 1977 harvest and the harvest in Hunting Dis- 

 trict 426 remained about the same. Overall, the harvest of mule 

 deer has dropped drastically from 835 to 200 in H.D. 410 between 

 1975 and 1978 and from 325 to 186 in H.D. 680 between 1975 and 



1978. Hunting District 426 has increased from 511-558 between 

 1975 and 1978. Data for the 1979 hunting season are not avail- 

 able; however, the overall harvest of mule deer will probably 

 increase in 1979, as mule deer were much more plentiful during 

 the 1979 hunting season. 



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