o 

 o 

 Q 

 o 



3 



0) 



E 



3 



1600- 

 1400- 

 1200- 

 1000- 

 800 

 600- 

 400- 

 200 

 



Actual Count 

 -»--■ Lincoln Index Estimate 

 •o— — Modeled Estimate 



— i 1 1 1 1 1 1 1 1 1 — 



1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 



Year 



Figure 2.1 



A comparison of the actual count of mule deer 

 during early winter helicopter surveys with 

 the Lincoln Index estimate and the modeled 

 estimate, 1977-1986. 



estimates. Modeling was also employed to calculate estimated 

 size and composition during years of partial or incomplete 

 aerial surveys and for 1968 when no survey was made. 



Population estimates for 1973-1975 were refined by 

 applying the average observability index for 1977-1979 (66.0%) 

 to early winter counts . Surveys during both periods were 

 flown by the same pilot (A) and principal observer (Mackie) 

 and were of egual coverage and intensity. Fawn survival and 

 known adult mortality on the study area and the adjacent NCRCA 

 research area (Knowles 1975, 1976) were also considered. 

 Estimates for earlier years when complete surveys were also 

 flown by Mackie and pilot A (1964, 1965, 1970, and 1971) were 

 based on a 60% observability factor because they were not 

 flown for as close or complete coverage of the study area as 

 those during 1973-1987. Estimates initially derived from 

 partial or no surveys during 1960-1963 (Mackie 1970) and 1966- 

 1969 were refined after comparison with estimates from full 

 surveys before and after years of partial surveys. Additional 

 data for modeling population size and composition were 

 available from helicopter surveys covering portions of the 

 study area in 1963, 1966, 1967, and 1972, a fixed-wing survey 

 in 1969, and from classifications along vehicle routes through 

 the area during autumn, winter, and spring 1960-1963. The 

 partial survey flights also provided a minimum count of deer 



40 



