mortality substitute for or add to natural mortality? Also, 

 does mortality from coyote predation substitute for emigration 

 or mortality from starvation and "old age"? 



Obviously, at least some hunting mortality substitutes 

 for natural mortality that would occur in any case; the 

 question is how much? Our data indicated that this varies 

 among sex and age classes and probably among locations and 

 species. Because forage conditions for survivors were not 

 improved as the result of death of individuals, substitution 

 probably only functioned on an exact basis. That is, if the 

 specific animal harvested was one that was "doomed" to die 

 overwinter, then that hunting mortality substituted for 

 natural mortality and was not additive to other mortality. On 

 the other hand, the harvest of a healthy, fat 3-year-old 

 female could not and did not prevent a malnourished fawn (or 

 16-year-old female) from dying. Similarly, the harvest of 

 deer in core habitat did not guarantee survival of deer in 

 marginal habitat. Thus, the degree of substitution depends 

 upon the varying annual percentage of the population 

 vulnerable to "natural" mortality. 



The impact of additive hunting mortality to the 

 population depended upon subsequent recruitment rates that 

 determined replacement. Thus, even though a varying degree of 

 hunting mortality was additive to other mortality, population 

 declines did not occur when recruitment was adequate to 

 replace that mortality. Because recruitment rates varied 

 substantially among years, the effect of any given rate of 

 hunting mortality also varied among years. 



Pre-season male: female ratios on our study area were not 

 much different in many years than those reported for unhunted 

 populations. Thus, much hunting mortality of adult males 

 appeared to substitute for high natural mortality which would 

 probably occur in the absence of hunting. Our data suggest 

 that the degree to which pre-season male: female ratios are 

 below about 40:100 may indicate the extent to which hunting 

 mortality of males is additive to natural mortality. 



Hunting mortality of adult females did not substitute for 

 natural mortality to the same extent as for males because of 

 lower natural mortality among females than males. Also, the 

 removal of adult females by hunting potentially affected 

 future population dynamics more than removal of males because 

 it more directly affected future numbers of fawns produced. 

 Because emigration by yearling females probably increased at 

 high densities, there is likely an increased degree of 

 substitution for hunting mortality of adult females by 

 yearlings remaining in or returning to the population. 



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