specific differences in recruitment and female age structure; 

 70% or more was related to factors influencing fawn survival 

 across all female age classes. The contribution by non-age- 

 related factors must have been even greater during 1972-1977 

 when age-related factors should have resulted in above-average 

 ratios . 



Although age-specific differences in recruitment are 

 interesting, valuable for comparison with deer in other 

 environments, have implications for individual survival, and 

 help explain condition cycles, they probably did not explain 

 major population changes on our study area. Some age classes 

 may be affected to a greater degree than others by conditions 

 influencing fawn recruitment (1984-85, Table 5.4), but major 

 changes in fawn recruitment apparently were the result of 

 factors affecting all age classes rather than individual age 

 classes . 



Fawn Mortality Related to Litter Size and Sex 



Proportions of fawns of single (38.7%) and twin (31.4%) 

 litters that died during summer, 1976-1986, were not 

 significantly different (X 2 =0.62, P=0.45, 1 df, n=167 fawns). 

 Mortality rate of male fawns (n=82) was not different for 

 litter size (X 2 =0.03, P=0.88, 1 df), nor was a difference 

 apparent for female fawns (X 2 =1.06, P=0.33, 1 df, n=85). 

 Overall, male and female fawns died at similar rates during 

 summer (X 2 =0.24, P=0.65, 1 df). However, during years of poor 

 fawn survival (1976, 1977, and 1983-1985), 62% of 37 female 

 fawns died and only 40% of 38 male fawns died (X 2 =3.01, 

 P=0.09, 1 df). During other years, no difference was apparent 

 in mortality of female (17%) and male (25%) fawns (X 2 =0.53, 

 P=0.48, 1 df). Although the relationship was statistically 

 marginal for this small sample, the possibility of lower 

 survival for female fawns during years of higher fawn 

 mortality may warrant further investigation. An additional 

 substantiation of this relationship was the fact that 9 of 10 

 fawns captured during December 1983 (a cohort of poor 

 survival) were males. 



Proximate Causes of Fawn Mortality 



Determination of causes of fawn mortality was based on 

 annual samples of 10-19 radio-collared newborn fawns during 

 1976-1986. Although these sample sizes were small, they 

 indicated the same trend in mortality rates during summer as 

 indicated by changes-in-ratios (Fig. 5.5). Generally, few 

 fawns retained radio-collars during autumn and winter, and 

 they were used only to determine cause of death during that 

 time. 



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