areas nearby, and 67% had beaver ponds in the vicinity (Table 3). 

 Components that were part of the habitat at half or more of the 

 sites with high bat activity, in addition to those mentioned, 

 were mature Douglas fir (50%), and mature hardwoods (50%), rock 

 outcrops (50%), and lodgepole pine forest (50%). No sites with 

 high bat activity had old buildings in the area (Table 3). 



These results are similar to those reported during the 1991 study 

 (Butts 1993). During 1991 and 1992, high and moderate bat 

 activity was associated with sites that had rock outcrops, beaver 

 ponds, mature hardwoods, or mature Douglas fir as components of 

 the habitat. 



All bat species, with the exception of Silver-haired bats 

 {Lasionycteris noctivagans) in Washington, were detected at 

 dramatically higher rates in old-growth stands than in young or 

 mature stands of Douglas fir in studies done in Oregon and 

 Washington (Thomas and West 1991). Bats were between 2.5 and 9.8 

 times more abundant in old-growth than in young or mature stands 

 in both regions. Thomas and West (1991) speculated that the 

 activity of the Myotis species, the Big brown bats, and the 

 Silver-haired bats in Oregon were more abundant in old-growth 

 because that habitat provided an increased variety and abundance 

 of day roosts. Perkins and Cross (1988) reported that all of the 

 Hoary bats and most of the Silver-haired bats in their study 

 roosted in old-growth Douglas fir. They speculate that Hoary 



31 



