Figure 6.5 



A simplified model illustrating adult female 

 mortality rates that will maintain a stable 

 female population and mortality rates for males 

 that will maintain selected male: 100 female 

 ratios given various recruitment rates. 



The model also indicates that within the normal range of 

 adult sex ratios, stable populations of females cannot be 

 maintained with a mortality rate similar to that of males. At 

 40 fawns recruited per 100 females, annual mortality rates for 

 adult males of 25%, 33%, 50%, and 67% would maintain post- 

 season sex ratios of 60 males:100 females, 40:100, 20:100, and 

 10:100, respectively. At the same recruitment rate, the 

 female population would decline if annual mortality exceeded 

 17%. Fawn recruitment of at least 12-18 fawns: 100 females is 

 necessary to replace the average annual natural mortality rate 

 of 6-8% for adult females. A harvest rate of 33% for adult 

 females would have reduced the female population during all 

 years 1960-1986, except 1979-80, when numbers would have 

 roughly stabilized rather than continued to increase. Also, 

 because female populations are larger than male populations, 

 an eguivalent harvest rate for the 2 sexes will result in a 

 higher numerical harvest of females. 



174 



