number of fawns lost annually. Recruitment of fawns to 1 year 

 of age averaged 35% of maximum potential and ranged from 83% 

 in 1979 to 4% in 1984. Generally, the loss of potential 

 production prior to mid-June was low, but was exceptionally 

 high during 1984 (38%) and 1985 (42%). Losses from the 

 estimated maximum production to mid-June included non- 

 breeding, non-pregnancy, less than maximum ovulation and 

 fertilization rate, abortion, resorption, stillbirth, and 

 immediate post-partum abandonment. 



Of fawns surviving to mid-June, an average of 42% (range 

 4-69%, Table 5.3) died by late September. The lowest rate of 

 mortality during summer was for the 1979 cohort; the highest 

 for the 1985 cohort. The rate of fawn mortality during summer 

 was less variable than during autumn and winter (Table 5.3). 

 Mortality was exceptionally low during summer 1979, but 

 exceeded 30% during all other summers except 1978 (28%). Of 

 all fawns dying between mid-June and the following May, 65% 

 died by the end of September. 



Mortality rate of fawns during autumn averaged 12% (range 

 0-35%), was lower than during any other season (Table 5.3), 

 was more variable (CV=113%) than during any other season, and 

 was generally either very low or very high. Highest mortality 

 was observed during 1975, 1976, 1977, and 1984. Overall, 

 however, only 9% of the fawns that died during their first 

 year of life died during autumn. 



Over-winter mortality rates averaged 33% (range 5-82%) 

 and accounted for 26% of all deaths of fawns. Although winter 

 was longer than other periods, almost all mortality occurred 

 by the end of March, so mortality rates were generally 

 comparable among seasons. Mortality rates during winter were 

 high during 1975-76, 1983-84, and 1984-85; moderate during 

 1977-78, 1981-82, and 1985-86; and lower during other years. 



Total annual mortality for fawns that were alive in mid- 

 June averaged 62% and ranged from 17 to 94%. Annual mortality 

 was less than 50% during only 4 of 12 years. Despite annual 

 mortality of fawns that usually exceeded 50%, population 

 growth occurred in some of these years. With no hunting 

 mortality, adult female numbers increased slightly from spring 

 1976 to spring 1978 despite annual fawn mortality of 72% for 

 the 1976 cohort and 75% for the 1977 cohort. Adult female 

 numbers increased substantially from 1978 to 1979, when annual 

 fawn mortality was 43%. Despite annual fawn mortality of 56% 

 and 42% and moderate hunting mortality of adult females, the 

 number of adult females also increased somewhat from spring 

 1981 through spring 1983. 



Seasonal estimates of fawn mortality were further refined 

 by calculating instantaneous monthly rates of mortality for 



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