ABSTRACT 



Eight species of vespenilionid bats were identified during field surveys on the Sioux 

 District. Custer National Forest in June and September 1994. Most of the 18 sites surveyed 

 were associated with water (springs, reservoirs, beaver ponds, stock ponds). 

 Species identified were long-eared myotis (Myotis evo(is), western small-footed myotis (M. 

 ciliolabrum) , long-legged myotis (M. volans), fringed myotis (M. thysanodes), silver-haired 

 bat (Lasionycteris noctivagans), big brown bat (Eptesicus fuscus) , hoary bat (Lasiurus 

 cinereus), and Townsend's big-eared bat (Plecotus townsendii). The literature on the bat fauna 

 of the Sioux District includes one species not detected in 1994, little brown myotis {Myotis 

 lucifugus) (Andersen and Jones 1971, Jones et al. 1973). Most Myotis species cannot be 

 distinguished with bat detectors (the primary survey tool in 1994), so M. lucifugus may 

 actually have been present (unidentified Myotis species were detected at nine sites). M. 

 thysanodes (an adult non-lactating female), caught in a mist net in the Slim Buttes, is a new 

 species recorded for the area. 



Current lists include 2 bat species from Chalk Buttes, 7 species from Ekalaka Hills, 8 

 species from the Long Pines, 6 necies from North Cave Hills, 3 species from South Cave 

 Hills, and 9 species from Slim Buttes; no survey work was conducted in Chalk Buttes in 

 1994. Only the list from Slim Buttes includes all species known to occur on Sioux District 

 lands. Only Eptesicus fuscus has been recorded from each of the six main units of the Sioux 

 District; with the exception of M. thysanodes, all other species have been detected on at least 

 three of the six units. 



Seven species are known to breed on the Sioux District, based on males with enlarged 

 testes, Iactating females, or females with embryos. One other species (Plecotus townsendii) 

 was present at sites in the Ekalaka Hills, Long Pines, North Cave Hills, and Slim Buttes 

 during the breeding season, is known to breed in the Black Hills to the south, and probably 

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

 status on the Sioux District at this time. Currently, nothing is known about which species 

 overwinter on the Sioux District. 



