SUMMARY 



This report documents the results of a study of bat occurrence in 

 the Pryor Mountains of south central Montana. The field research 

 was conducted from 15 June to 10 September, 1989. Bats were 

 captured in mist nets set over ponds, streams, and springs and at 

 the entrance of two caves. Numbers of bats captured were 

 greatest at Little Ice Cave and at Mystery Cave. Capture success 

 was considerably lower at water sources, but a greater diversity 

 of species were captured at these sites, particularly at Sage 

 Creek campground and Gyp Spring. Most of the species captured 

 occurred throughout the area, with the exception of the pallid 

 bat, Antrozous pallidus . and the silver-haired bat, Lasionycteris 

 noctivaqans , which were more restricted in distribution. Eight 

 individuals of Antrozous pallidus were captured at Gyp Spring. 

 This species was known previously in Montana from only one 

 specimen taken at Gyp spring (Shryer and Flath, 1980) . Of the 

 eight individual pallid bats netted in 1989, four were lactating 

 females, indicating that this species breeds in Montana. Several 

 of the species of bats found in the Pryor Mountains were captured 

 in numbers significantly different from an expected 1:1 sex 

 ratio. This was especially true at Mystery Cave and Little Ice 

 Cave, suggesting that in some species, males and females may be 

 differentially utilizing habitat. Bat activity at both Mystery 

 Cave and Little Ice Cave indicated that these caves provide 

 important summer roosting habitat for bats. Additionally, both 

 caves possess characteristics which may make them important as 

 hibernacula. 



