Unlike the spotted bat, the Townsend's big-eared bat's call is 

 inaudible to the unaided human ear, and it is not easily 

 distinguishable from other bats with electronic bat detectors. 

 Also, the energy level of this bat's call is relatively low. 

 Thus aural monitoring was not practical for this species. 

 However, the observation of 11 individuals in 1990 confirms the 

 summer occurrence of this species in the study area. One of the 

 specimens captured was a juvenile, suggesting that this species 

 breeds in the area. During the summer, this species may roost in 

 a variety of locations, ranging from abandoned buildings to caves 

 or abandoned mines (Kunz and Martin, 1982) . Individuals may be 

 spread out, and it may be difficult to locate a significant 

 number of individuals to determine abundance, especially if 

 population numbers are small. This species tends to favor 

 roosting near the entrances of mines and caves for hibernation 

 (Humphrey and Kunz, 1977; per. obs.) and tends to remain in the 

 same area throughout the year (Kunz and Martin, 1982). 

 Therefore, examination of potential hibernation sites may be an 

 effective means of determining the abundance of this species in 

 the area. 



The capture of 17 additional pallid bats, including several 

 lactating females and juveniles, suggests that they breed in the 

 area. This species was encountered frequently at the sites where 

 it was captured, and it seems likely that this species may be 

 locally common in the area. 



It would be particularly desirable to continue work on the two 

 candidate species under consideration for listing by the U.S. 

 Fish and Wildlife Service, Euderma maculatum and Plecotus 

 townsendii . In the case of the spotted bat, additional work 

 could take several directions. Wai-Ping and Fenton (1989) have 

 successfully radio-tagged this species in order to obtain 

 information on foraging and roosting areas and habits. Such a 

 program could be undertaken in the Bighorn Canyon NRA and 

 surrounding area in order to identify significant areas of usage 

 by this species. Such research would be labor intensive and 

 costly however. A more immediate concern should probably be the 

 identification of the distribution pattern of this species. An 

 examination by boat of the Bighorn Canyon between Barry's Landing 

 and Big Elk Creek to the north revealed potential spotted bat 

 habitat. The area is characterized by high (300 m) cliffs and is 

 similar to habitat described by Woodsworth et al., (1981) and 

 Watkins (1977) . Monitoring throughout the area, including 

 spending a significant amount of time in the canyon, would 

 provide information on this species' distribution and habitat use 

 throughout the area. 



Only a gross description of cave structure was possible in this 

 study, and the descriptions of Cambell (1978) are limited. 

 During the summer of 1991, a caving group associated with 

 Washington State University is planning to do extensive mapping 



18 



