Short-eared Ow1 . A snectacular increase in short-eared owl density 

 was apparent in 1979. While only two owls were recorded in 1977-1978 May- 

 July runs of the five roadside routes (30 runs total), 25 registrations 

 were made in 1979 (15 runs). Although no nests were discovered by pro- 

 ject biologists, local ranchers reported that nests were fairly common. 



Eastern Kingbird . Eighteen nests were located in the Mine Study 

 Area; the average number of eggs or young per nest was 3.0 (n=13, range=l-4). 



Loggerhead Shrike . Six nests were located in the Mine Study Area; the 

 average number of eggs or young per nest was 5.3 (n=4, range=4-7). 



Desert Co ttontail . Results of the 1979 lagomorph survey are presented 

 in Table 4. While no cottontails were observed during this survey, 1979 

 data do not differ significantly from the 1978 data (p -.05) (figure 6). 



White-tailed Jackrabbit. The number of jackrabbits observed during the 

 1979 lagomorph survey (table 4) does not differ significantly from the 

 number observed in 1978 (t-test, p-. 20) (figure 6). 



Mule Deer . A summary of mule deer observations during the study period 

 is presented in table 5. Production ratios obtained during the period 1977- 

 1979 are shown in figure 7. These were based on September-October data 

 since summer foliage cover limits observability of fawns prior to September 

 and since hunting mortality influences November population age structure. 

 The 1979 production ratio was 118 fawns/100 does, the highest obtained 

 since the study began in 1977. 



Aerial census data are presented in table 6. It should be emphasized 

 that the low numbers of deer observed during the summer reflect decreased 

 observability and do not necessarily indicate a corresponding decrease in 

 abundance. Since observability is highest in winter, both density and dis- 

 tribution estimates are based on the winter aerial census. Figure 3 shows 

 winter density indices obtained since 1976. Since the census data in 

 table 6 represent the minimum number known present (i.e., there were at 

 least 208 mule deer present during the December flight, but there may 

 actually have been more that were not seen), the density indices shown in 

 figure 8 may be somewhat lower than true densities. The data indicate an 

 increase in mule deer winter density in the Mine Study Area since the last 

 monitoring period, although the Permit Area showed a decrease. The control 

 area appears to support considerably higher winter densities of mule deer 

 each year than does the Permit Area. 



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