water during wet summers and from 0.805-2.41 km during dry 

 summers. During wet autumns, more elk than deer were 

 distributed within 0.805 km and at greater than 2.41 km from 

 water. During winter and spring, when the availability of 

 free water might be considered least important, deer were 

 significantly closer to water sources than were elk. 



Mule Deer and Cattle 



Although some changes in livestock grazing patterns on 

 the study area occurred and may have influenced changes in 

 spatial distribution between periods of intensive study in the 

 early 1960s and 1975-1986, the lack of data on cattle 

 distribution and habitat use precluded statistical comparisons 

 with distribution and habitat use by mule deer and elk. Our 

 observations generally supported those of Mackie (1970). 

 During hot, dry summers and autumns, cattle made much more 

 extensive use of timbered areas and second and third order 

 drainages than during wet or "normal" years. This indicated 

 they could potentially have an impact on deer at that critical 

 time. However, because most heavy use of timbered types by 

 cattle was near water sources during hot, dry periods and much 

 of the timbered types did not contain water sources, potential 

 impacts were somewhat reduced. 



As discussed in Chapter 7, we believe it possible that 

 some changes in distribution of mule deer between the 1960s 

 and the 1970s and 1980s may have been related to changes in 

 the distribution and seasonal grazing patterns of cattle. 

 Because of the lack of quantifiable data, however, we cannot 

 prove that those changes were more than coincidental. 



Campbell and Knowles (1978) indicated that highly mobile 

 elk actively selected rested pastures over grazed pastures in 

 a rest-rotation system in the Missouri River Breaks (NCRCA) 

 and selected the most lightly grazed areas in other grazing 

 systems. The shifting of elk distribution away from areas of 

 intensive use by cattle could result in increased competition 

 between elk and less mobile mule deer. 



All of these considerations indicate the potential for 

 impacts on mule deer by cattle grazing, but we have no 

 evidence that mule deer populations were adversely impacted. 

 One problem with investigating impacts of cattle grazing on 

 wildlife in the western United States is that there are few or 

 no areas of significant size where livestock grazing in some 

 form does not occur. Thus, we know nothing about mule deer 

 distribution, habitat use, and population performance in the 

 absence of livestock. The mule deer distribution, food 

 habits, habitat use, and population performance we report 

 probably all reflect adaptation to the long-term presence of 

 cattle . 



270 



