Tuttle and Stevenson (1978) suggest that those caves that possess 

 structural and elevational complexity and a wide thermal range 

 provide the greatest diversity of roosting sites. Tuttle (1979) 

 found that of 1635 known caves in Alabama, only 2.4% were used by 

 gray bats ( Myotis griscens) in summer, and only .1% were used in 

 winter. Larger, more complex caves may provide suitable roosting 

 habitat for a diversity of species (Dalquest and Walton, 1970) 

 and may provide sites for larger aggregations of these species 

 (Kunz, 1982). While caves are numerous in the Pryor mountains, 

 most are small and horizontal (Cambell, 1978). The few large 

 caves found in the area may be of primary importance to bats, and 

 were a primary focus of this study. 



Of the many caves known in the area, one is known to have been 

 used as a hibernaculum by Plecotus townsendii (D. Center, per. 

 comm) , and two of the larger caves were found to be occupied by 

 four species of Myotis during the summer of 1989 (Worthington and 

 Ross, 1990) . 



This study was conducted largely to expand the base of 

 information available on the species of bats occurring in the 

 Pryor Mountains. The large number of caves in the area, combined 

 with a diversity of habitats, together with information gathered 

 from research conducted in 1989 (Worthington and Ross, 1990) and 

 from previous studies, suggested that the Pryor Mountain area 

 could support a large diversity of bat species, including those 

 discussed above that are potentially rare. The information 

 presented in this report provides additional information 

 regarding the distribution, abundance, and ecology of these 

 species. Such information is useful both from a scientific 

 perspective, given that ecological information is very often 

 lacking for the species considered in this study, as well as from 

 a management perspective. The Federal Cave Resources Protection 

 Act of 1988 mandates that federal agencies identify significant 

 caves and manage for their protection. The caves discussed in 

 this report may warrant such management. The two candidate 

 species, together with Antrozous pallidus and the more abundant 

 species, may require special management consideration. The 

 information gathered from this study will assist the federal 

 agencies involved in management of the Pryor Mountain area in 

 making management decisions for bats as well as caves and their 

 biological resources. 



STUDY AREA 



This study was conducted in the Pryor Mountains, approximately 72 

 km south of Billings, Montana. The area is primarily federal in 

 ownership, and is administered by the Bureau of Land Management, 

 the Custer National Forest, and the National Park Service. The 

 Crow Indian Reservation borders the northern portion of the area, 

 and small portions of private land are dispersed throughout the 



