that nebulous category. Some tests were run using STATISTIX version 2.0 (Analytical 

 Software; Tallahassee, Florida). 



RESULTS 



General Summary of External Surveys 



External inspections of 173 workings at 88 abandoned mine sites were documented in 

 1997-1998 during this survey (Table 1). Of these workings, 77 were adits, 90 were "shafts" (see 

 Methods), and 6 were pits. Ninety-two workings were monitored for bat activity at least one 

 night: 78 with bat detectors and 39 (14 exclusively) with mist nets and/or a harp trap. Some 

 workings were monitored more than once using more than one method (Table 1). Elevation of 

 mine workings ranged from 4970' to 8700'. Monitored adits (46) and shafts/pits (46) were 

 distributed similarly by elevation (Fig. 1; G= 1.780, df = 2, P > 0.4). Dominant vegetation 

 (cover type) was recorded at 87 (94.6%) of the monitored mine workings, of which 76 (87.4%) 

 were in sagebrush steppe. Remaining cover types at mine workings included grassland (1), 

 Douglas-fir (5), mixed conifer (1), spruce/fir (3), and whitebark/limber pine (1). 



Evidence of bat use was gathered at 66 workings of 49 mine sites, ranging in elevation 

 from 4970' to 7640', while elevation range of unused mine workings was 5150' to 8700'. Of 

 these, in-hand identification of bats was made at 20 workings of 16 mine sites (Table 2). Bat 

 activity was recorded by bat detectors at 50 workings of 40 mine sites (Table 3); of these, 41 

 workings at 30 mine sites were at locations where bats were not visually identified. Bat use 

 based only on the presence of guano (usually only one or a few pellets) was recorded at 5 

 workings of 4 mine sites. Bat activity was recorded at 48 (63.2%) of the workings in sagebrush 

 habitat, 4 (80%) in Douglas-fir habitat, each single working in the grassland, mixed conifer, and 

 whitebark/limber pine habitats, and none of the workings in spruce/fir habitat. 



Bat Species Captured or Observed 



During 1997-1998, 64 bats representing four species were captured or observed at 20 

 different workings of 16 mine sites (Table 2). Six individuals of two species may have been 

 sampled twice < two weeks apart at the unnamed adit T4SR8WS18SENW, as the sexes and 

 numbers of each species in each sample were identical. However, forearm measurements and 

 scars did not closely match, so here I assume that 12 different individuals were captured. The 

 Western Small-footed Myotis (Myotis ciliolabrum) represented 78. 1% of the total (n = 44 m, 5 f, 

 1 ?), Western Long-eared Myotis (M evotis) 14.1% (n = 7 m, 2 f), Townsend's Big-eared Bat 

 (Corynorhinus townsendii) 4.7% (n = 2 m, 1 ?), and Big Brown Bat (Eptesicus fuscus) 3. 1% (n = 

 1 m, 1 ?). These species were captured or observed at 17, 5, 3, and 2 workings, respectively. 

 Maximum number of captures during nights when bats were captured (n = 17) was 9 bats, the 

 mean was 3. 12±2.29/night. Successful trapping occurred between 1 1 June and 21 August. 



Sex ratio of the 61 bats assigned to sex was extremely male-biased (7.71 males for every 

 female). Sex ratio for the two Myotis species combined was 7.29 males: 1 female (G = 37.683, P 

 « 0.001). Sex ratio of each species wasM ciliolabrum = 8.8 males: 1 female (G = 17.817, P « 

 0.001), andM evotis = 3.5 males: 1 female. 



Evidence of reproductive activity was scant. A lactating female M evotis was captured 

 on 6 August 1998 at the unnamed adit T4SR8WS18SENW, a second lactating female M evotis 

 was captured on 17 August 1998 at the same adit. Three female M ciliolabrum with evident 

 teats (non-nursing) were captured on 1 1 June 1998 at the unnamed adit T3SR7WS8SESE. Three 



