Many of the bats in the Pacific Northwest have a strong association with lower-elevation, old-growth forests that is believed to be the result of bats selecting roosts located in the cracks, peeling bark, and cavities of snags and damaged trees predominantly found in these older forests (Thomas and West 1991). However, in most areas in this region, such old-growth stands have been harvested, being replaced with young, structurally simplified Douglas-fir (Pseudotsuga menziesii) stands. Mount Rainier National Park represents the largest area of late-successional forest in the Cascade Range of southern Washington (see map), and likely serves as an important refugium for many of these bat species.