Habitat f/ye— Bats were detected in most habitat types, from early serai "disturbance" sites in 

 recent clearcuts and bums to mature and old-growth stands, in ponderosa pine and riparian sites 

 at low elevation to Engelmann spruce and subalpine fir at moderate elevation. Riparian, 

 "disturbed", and old-growth/mature sites accounted for 72.3% of the 188 sites sampled with bat 

 detectors, and are the only habitat categories analyzed here. Presence was not imiform across 

 these habitat categories. Bat activity occurred significantly more frequently in old-growth/mature 

 forest (Table 1: 71.4% of sites) than in "disturbed" forest stands (46.7% of sites). Much of the 

 difference was attributable to Myotis sp., but nearly all species identifiable were found at a 

 greater proportion of old-growth/mature sites (Table 1), with the exception of the silver-haired 

 bat {Lasionycteris noctivagans). The long-eared myotis (M evotis) was the only species where 

 the difference was significant, but larger sample sizes would likely show the same pattern for the 

 big-brown bat {Eptesicus fuscus) and hoary bat (Lasiurus cinereus). Bats appeared in equal 

 proportions of old-growth/mature and riparian sites (Table 2), except for the hoary bat {Lasiurus 

 cinereus), which was present at a significantly greater proportion of old-growth/mature sites (it 

 was not detected in any of the 36 riparian sites). 



The patterns of habitat occurrence noted on the Kootenai National Forest are similar to those 

 found in other studies in western North America. Old-growth and mattire forests, which have a 

 more complex structure often show greater bat activity than younger or disturbed forest stands 

 (see Perkins and Cross 1988, Thomas 1988, Thomas and West 1991). The availability of large 

 snags, a component infrequently foimd in young and disturbed stands, is recognized as one of the 

 most important attributes of old-growth and mature forests for bats in western North America 

 (Christy and West 1993, Gellman and Zielinski 1996, Mattson et al. 1996, Wunder and Carey 

 1996), as large snags provide important roost sites. The lack of association of Townsend's big- 

 eared bat to any forest type during this survey (Table 1 and 2) is consistent with its known habits 

 of roosting in buildings, bridges, caves and mines (Christy and West 1993, Wunder and Carey 

 1996). This species rarely if ever roosts in tree cavities; forests are used primarily for foraging. 

 The relatively uniform occurrence of the silver-haired bat amongst old-growth/mature, 

 "disturbed", and riparian sites in this survey is imusual relative to other studies (Perkins and 

 Cross 1988, Thomas 1988, Campbell et al. 1996, Mattson et al. 1996) where old-growth is the 

 habitat of greatest occurrence. It is not clear why our fmdings differ from previous studies. 



It is not surprising that activity at riparian sites was equal to that of old-growth/mature sites 

 (Table 2), as bats need water, and insect activity is often high at water sources (Christy and West 

 1993). The lack of hoary bat activity in riparian sites is surprising, however, as this species 

 routinely roosts and forages among deciduous trees in other areas (Jones et al. 1983). Perhaps 

 the riparian sites we sampled had too few large trees to be attractive. 



