of alternate prey and create advantageous hunting and killing 

 conditions for coyotes preying on deer. 



Net emigration of yearling females during some years, 

 although enhancing adjacent populations in marginal habitat, 

 resulted in "mortality" or reduced recruitment to the female 

 population on the study area. Induced primarily by behavioral 

 factors, emigration may act periodically as a natural 

 population regulating mechanism by reducing population growth 

 rate following several years of low fawn survival at either 

 low or high female densities. Overall, however, it did not 

 appear to be of singular importance in limiting numbers and 

 the population dynamics of mule deer on the area. Rather, 

 dispersal in the early years of increase following population 

 declines or lows may benefit recovery by rapidly refilling 

 vacant habitats capable of sustaining and producing deer 

 during periods of favorable environmental conditions, both on 

 and off of the study area. This, at high densities, may also 

 serve to maintain deer in more marginal habitats during years 

 of good conditions. 



Considering all other factors affecting the population, 

 hunter harvests that were not adjusted to periodically low 

 recruitment and increased natural adult mortality rates 

 directly reduced the population and influenced trends and 

 dynamics over periods of one to several years. Although 

 hunting generally did not significantly influence fawn 

 recruitment rates, its role in reducing the number of adult 

 females on the area, in conjunction with other mortality 

 factors, did influence absolute numbers of fawns/yearlings 

 recruited and, thus, also population trends during some 

 periods. The fact that hunting mortality, especially among 

 adult females, was largely additive to other mortality 

 indicated that hunting can be an important regulatory factor 

 or mechanism in the population at times. However, its overall 

 effect in determining trends through the years was minimal 

 relative to environmental variation. 



Although any attempt to model the role or importance of 

 various single factors on the population is unrealistic, 

 considering all interactions involved, it may be somewhat 

 indicative of the relative contribution of some factors to 

 trends we observed. For example, for 7 years from December 

 1980 through December 1987, the population increased from 

 1,175 to 1,405 mule deer, though not in a straight-line manner 

 (Fig. 4.2). Despite this growth, many "potential" deer were 

 lost to the population. 



If no mortality other than a few deaths from accidents 

 and old age had occurred and reproduction had been at the 

 maximum observed rate each year, simple arithmetic modeling 

 shows that the population could have increased to 38,840 deer 



317 



