were areas that had been preempted by established matriarchs. 

 Home ranges that included the stable "core blocks" were passed 

 on through the matrilineal family. As long as the matriarch 

 remains alive, however, female fawns must establish their own 

 "parturition territory" (Ozoga et al . 1984) in areas adjacent 

 to that of their mother. Thus, "core blocks" become larger 

 "core areas" and include the "parturition territories" of 

 several generations. The pattern of dispersion for the 

 population indicated that in rapidly increasing populations, 

 marginal habitat is filled as female fawns recruited in "core 

 areas" must establish their own "parturition territories" at 

 some distance away from that of the original matriarchs. All 

 of this leads to a density distribution (Fig. 7.1) that 

 appears as aggregated areas of high use surrounded by roughly 

 concentric areas of lower, declining use. Mature males and 

 yearlings of both sexes were relegated to areas not preempted 

 by productive females . 



It was apparent that not only did different sex and age 

 classes most often occur in different social groups, but they 

 also tended to occupy different land areas during most of the 

 year. Thus, for many analytical purposes, the different sex 

 and age classes should be viewed as separate populations 

 rather than as a homogeneous "mule deer population". Clutton- 

 Brock et al . (1982) also indicated that male and female red 

 deer, at least, should be viewed as separate populations. For 

 some analyses, it may be valid to treat mature females and 

 their fawns, non-productive females, yearling males, and 

 mature males as 4 separate populations. 



Collectively, the information from marked deer indicated 

 that matrilineal groups are the predominant social group for 

 mule deer in the Missouri River Breaks. The predominance of 

 matrilineal social groups and their structure was very similar 

 to that reported for white-tailed deer by Hawkins and Klimstra 

 (1970) and Ozoga et al . (1982a). The association of mother 

 and daughter was known to last a minimum of 8 years . The 

 relatively low level of dispersal by yearling females 

 contributed to the formation of matrilineal groups. The 

 degree of association between mother and daughter generally 

 declined with age, but that was probably primarily related to 

 the increasing likelihood that the daughter had her own fawns 

 and became more likely to form her own matrilineal group. 

 When both mother and daughter recruited fawns, reassociation 

 often did not occur until mid-to-late-winter. Data on group 

 characteristics from the entire population also indicated that 

 females were less likely to group with other females when fawn 

 survival was high. However, a 12-year-old female and her 7- 

 year-old daughter were known to reassociate by early autumn 

 when neither had living fawns. Matrilineal groups were known 

 to contain a minimum of 3 generations; a matriarch, her 

 daughter (s), and fawns of both the matriarch and her previous 



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