FINDINGS 



Mule Deer 



Western Segme nt 



Mule deer are the most numerous and widespread of the three 

 big game species found in the study area. During the course of 

 the project, observations were made on a total of 2,970 mule deer, 

 with many of these observations during the critical winter periods 



Distribution 



While mule deer can generally be found seasonally throughout 

 the study area, they are primarily associated with the Missouri 

 River, Teton River, Marias River, and Arrow Creek breaks and 

 their associated tributaries. They can also be found in the 

 foothills of the Highwood and Bearpaw mountains. The Missouri 

 River Breaks and its tributaries form the major habitat for this 

 species. Figure 9 presents the general winter distribution of 

 this species and the critical winter range. The critical winter 

 range was determined by observations during two severe winters 

 (1977-78 and 1978-79) when deep snows and extreme temperatures 

 greatly restricted deer movements. During these extreme condi- 

 tions, deer made much greater use of the rugged sagebrush breaks 

 along the Missouri and Marias rivers as well as the major tribu- 

 taries, such as Arrow Creek. In more mild winters (1975-76 and 

 1976-77), deer were found wintering in Rowe and Crow coulees with 

 their open terrain and gradual topography. 



In the 1977 progress report, data on seasonal use of vegeta- 

 tion, slope, exposure, and topography were reported. From these 

 data, it was found that mule deer are most limited in distribu- 

 tion and habitat use during the winter. In winter they are found 

 in the sagebrush-grassland vegetation types on the sidehills and 

 ridges of the river, tributary streams and coulee breaks. Here 

 on south facing and wind blown slopes, they find available forage 

 and protection from the elements. In the spring there is a gen- 

 eral movement out of these rugged breaks into the surrounding 

 benchlands and creek bottoms. The greatest variety in use of 

 habitat is found at this time of year. In late summer and early 

 fall there is a further shift toward greater use of agricultural 

 and open habitat types. This expansion of seasonal range is fol- 

 lowed by a returned to the breaks-type habitat during late fall 

 and winter. 



Mule deer used islands in the Missouri River for fawning. 

 Does were commonly found on islands with dense willow cover dur- 

 ing the month of June. When searches were conducted fawns were 

 usually present. These islands provide dense cover and security 

 from predators for the fawns, and along with other riparian areas, 

 appear to be a critical habitat component at this time of year. 



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