- Losses due to relocation of the Burlington Northern 

 Railroad grade (725 acres of winter range) ; 66-119 

 v/hite-tailed deer. 



- Qualitative loss estimate - high. 



6) Derivation of Loss Estimates 



The main impact to the v/hite-tailed deer population occurred 

 through the loss of crucial winter habitat. Loss of other seasonal 

 habitats was insignificant when compared to this loss and it was 

 assumed the majority of the deer impacted by the loss of spring 

 through fall ranges were also impacted by the loss of winter range. 

 In the determination of actual animals lost from the two segments 

 of the white- tailed deer population, the available density esti- 

 mates were combined with the acres of crucial winter range lost to 

 produce an estimate of the animals lost from the population. Ihis 

 method assumes the deer are uniformly distributed on the winter 

 range for the entire winter period and each acre of winter range is 

 of equal value. This is not actually the case, as the deer shift 

 their distribution in response to changing snow accumulation pat- 

 terns. In addition, deer concentrate along the bottomlands during 

 periods of severe winter weather (Blair 1954b), and these areas 

 were more important to maintaining the population than were the 

 upper benches. However, due to the large size of the impact aiea 

 and the inadequacy of available studies to aid in the determination 

 of losses, and because no better method could be found, this method 

 of impact analysis was used. 



Habitat loss estimates due to the project were determined by: 

 1) measuring the amount of historical white-tailed deer winter 

 range inundated by the reservoir; 2) multiplying the miles of 

 Highway 37 bisecting crucial winter range (11.3 miles) by the 

 acres of habitat lost per mile (26.7 acres); and 3) multiplying tlie 

 miles of railroad grade through the crucial winter range (19 

 miles) by the average acres of hcibitat lost per mile (38.2 acres). 



The density figures observed by Zajanc (1948) were used to 

 determine the absolute mLnimum loss of deer resulting from the 

 inundation of the impoundment area. A white-tailed deer density of 

 .037 deer/acre was combined with the estiiriated loss of habitat, 

 11,000 acres, to produce an estimate of 407 white-tailed deer lost 

 from the pre-impoundment population. Tliis loss has to be con- 

 sidered minimal because the original density estimates were based 

 on ceiTSus strips chat included a large ar-.iount of upland areas 

 (where wintering populations are known to be less) and areas not 

 associated with crucial winter ranges. Tnerefore, they were not 

 representative of the higher v/hite-tailed deer densities impacted 

 due to the loss of rioariaj-! habitat. 



White-tailed densities observed during tlie various studies 

 along the lower Fisher River were originally assumed to !:« the same 



22 



