deer population trends and dynamics. Deer numbers fluctuated 

 widely through the years, and in recent years were as high or 

 higher than at any time in the past, while browse plant 

 abundance was relatively unchanged. During periods when there 

 appeared to be some general correlation between deer numbers 

 and utilization, use tended to follow rather than precede 

 changes in population size. 



Deer population trends and dynamics through and following 

 severe winters were particularly enlightening with respect to 

 the role and importance of winter range and forage supplies. 

 During several of the most severe winters (e.g., 1968-69, 

 1977-78, and 1978-79) when deer were most concentrated and 

 forage and winter range were most limited, mortality of both 

 fawns and adults was light to moderate. Subsequent fawn 

 production and survival was generally high. In fact, fawn 

 production and survival in 1979, following what may have been 

 the most severe winter during the study, was the highest 

 recorded. Those trends clearly were influenced by range 

 forage conditions the previous summer and other interacting 

 factors, not by the amount of winter range or "key" browse 

 forage available. Such findings lead us to question the 

 generalization or "principle" that winter range and forage 

 supplies are invariably limiting, or that winter, when range 

 and forage is most limited, represents the "bottleneck" in 

 deer management in northern environments. 



Because these findings contrast sharply with 

 long-prevailing concepts, perhaps it is necessary to ask why 

 and what, if anything about the study, study area, or findings 

 differed significantly from other works. 



Most studies related to deer have been short term and 

 concerned primarily with either plants or animals. Few, if 

 any, studies have been long term and coupled information 

 simultaneously on ungulate and plant demography (Macnab 1985) . 

 Thus, our information on the relationship of forage quantity 

 and deer numbers may not really be an exception when compared 

 to the few other studies that collected information on both 

 plant and animal numbers. We can compare our findings with at 

 least 2 other studies on mountain-foothill ranges where mule 

 deer were dispersed during summer but typically very 

 concentrated during winter. One major interpretive difference 

 is that our data were collected for a deer population that 

 remains relatively dispersed over its range except in the most 

 severe winters . 



Studies by Wallmo et al . (1977) of a migratory mule deer 

 population in north central Colorado indicated that forage 

 quantity on summer through early winter range was enough to 

 support more than 30 times the number of deer that actually 

 occurred. Forage quantity on late winter range would have 



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