DESERT MULE DEER USE OF GRAZED AND UNGRAZED HABITATS

We studied use of pastures and habitats in relation to moderate cattle grazing for 19 radio-collared desert mule deer (Odocoileus hemionus crooki) in a southeastern Arizona grass-shrubland. For each deer, use of grazed or ungrazed pastures and habitats in relation to their availability within the deer's home range was tested on a seasonal and annual basis. Deer, especially females during summer, tended to use currently ungrazed protions of their home range and dry wash habitats more than expected. Most deer showed a strong preference for ungrazed dry wash habitats, followed by grazed dry washes and ungrazed uplands. Although deer used grazed uplands less than expected based on availability, deer were still observed frequently in this abundant type. Deer use of currently ungrazed habitats may have been due to absence of cattle or to effects of recent cattle grazing in these habitats. During 2 years of favorable precipitation and forage conditions deer appeared to be adjusted to moderate rest-rotation cattle grazing. Leaving some areas periodically ungrazed might also provide a contingency for deer against impacts of cattle grazing during drought.