RESULTS AND DISCUSSION 



Eighteen sites were surveyed during 1994: 10 sites in mid-June and 8 sites in late 

 September (see Appendix B2). All main units of the Sioux District were sampled, with the 

 exception of Chalk Buttes: 2 sites in Ekalaka Hills. 4 sites in the Long Pines. 6 sites in North 

 Ca\c Hills. 2 sites in South Cave Hills, and 4 sites in Slim Buttes. All sites were sampled 

 vt ith ultrasound bat detectors, and three of these sites (one in North Cave Hills and two in 

 Slim Buttes) were sampled with mist nets as well (Appendix B2). Bats were detected at 13 

 (72%) of the sites, 12 of 18 sites using bat detectors and 2 of 3 sites using mist nets. A mean 

 o\ 2.7 _+ 15 species were detected at sites where bats were present; the largest number of 

 species at a single site ( 6 at Reva Gap Campground, Slim Buttes) were detected using a 

 combination of bat detectors and mist nets. 



Eight species of vespertilionid bat (common names follow Jones et al. 1986) were 

 identified during 1994 field surveys (see Appendix B3): Long-eared Myotis (Myotis evotis; 2 

 sites). Western Small-footed Myotis (M. ciliolabrum; 1 site), Long-legged Myotis (M. 

 volans; 2 sites). Fringed Myotis (M. thysanodes; 1 site), Silver-haired Bat (Lasionycteris 

 noctivagans; 4 sites). Big Brown Bat (Eptesicus fuscus; 10 sites). Hoary Bat (Lasiurus 

 cinereus; 2 sites), and Townsend's Big-eared Bat (Plecotus townsendii; 4 sites). Unidentified 

 Myotis sp. were detected at 9 sites. The Little Brown Myotis (M. lucifugus) has been reported 

 previously but was not identified in 1994; because of the difficulty of distinguishing the 

 species of Myotis on calls alone, and the presence of unidentified Myotis at nine sites, this 

 species may well have been present. The Fringed Myotis (an adult non-lactating female) 

 represents a new species reported for the Sioux District. Thus, the total number of bat species 

 known to occur on the Sioux District is nine. 



Current lists (see Appendix B4) include 2 bat species from Chalk Buttes, 7 species from 

 Ekalaka Hills, 8 species from the Long Pines, 6 species from North Cave Hills, 3 species from 

 South Cave Hills, and 9 species from Slim Buttes. Only Slim Buttes includes all species 

 known to occur on Sioux District lands, and only the Big Brown Bat has been found in all six 

 main units of the Sioux District. With the exception of the Fringed Bat. all other species have 

 been detected on at least three of the six units. Seven species (M. evotis, M. ciliolabrum, M. 

 lucifugus. M. volans, L. noctivagans . E. fuscus, L. cinereus) are known to breed on the Sioux 

 District. This knowledge is based on males with enlarged testes, lactating females, or females 

 with embryos. P. townsendii was present at a number of sites during the breeding season, is 

 known to breed in the Black Hills to the south (Turner 1974. Turner and Davis 1970). and 

 probably breeds in the area. Only M. thysanodes. which also breeds in the Black Hills, is 

 currently of uncertain status on the Sioux District. Nothing is known, however, about which 

 species overwinter on the Sioux District. Two, perhaps three, additional species may appear 

 in the area: the Northern Long-eared Myotis (Myotis septentnonalis), the Red Bat (Lasiurus 

 borealis). and possibly the Spotted Bat (Euderma maculatum). Species accounts follow, which 

 summarize distributional and life history information for all (detected and potential) species on 

 the Sioux District. Distribution maps show results of the 1994 survey. 



