Echolocation transects were conducted at 3 6 sites in the study 

 area. At some sites (e.g., Yaak River Campground) bat activity 

 was so intense that accurate counts of passes and feeding buzzes 

 could not be made. Similar conditions often occurred for brief 

 periods of time at other locations. Data were collected from 24 

 sites in the study area that were visited on two sample nights. 

 For purposes of establishing a comparative index of bat activity 

 for each survey location, a count was made of all passes and 

 feeding buzzes detected for 0.5 hours following the start of 

 audible bat activity on each night. This method of analysis 

 eliminates blocks of non-activity that result from beginning 

 monitoring too early in the evening from calculations. The number 

 of passes and buzzes were multiplied by two, to express them as 

 passes and buzzes per hour. The passes and buzzes per hour of two 

 trials at each site were averaged to yield an overall index of bat 

 activity for each site. At some transect locations, sampling for 

 0.5 hours after the start of bat activity was not accomplished for 

 one of the two trials. Sampling at these sites was typically 2-3 

 minutes short of 0.5 hours. Data from these sites were included 

 in the analysis, and contained in parentheses. Foraging 

 percentage was calculated as the percentage of total bat passes 

 containing a feeding buzz detected at the 24 transect locations. 



Mine survey methods 



Several adits were investigated for evidence of bat activity and 

 suitability as bat habitat. Care was taken to minimize 

 disturbance to bats that might be present (Perkins 1993) . Some 

 adits were also set with mist nets to capture any bats that might 

 use them. 



