The Tillet ponds (T. 58 N., R 96 W. , Sections 22 & 23, Bighorn 

 Co., WY; elevation: 1402 m) are located on private land in 

 sagebrush-grassland. These ponds may be difficult to net, due to 

 their large size and the extensive vegetation surrounding them. 

 These areas should be monitored with a bat detector. The ponds 

 proximity to Gyp Spring suggests that those species caught at Gyp 

 Spring, including the pallid bat, may occur here as well. 



Several wells and windmills are indicated on maps along the Gyp 

 Spring road. All of those investigated were dry, and most did not 

 appear to have been used within several years. None of the 

 windmills were functional. Several other developed springs were 

 located in the higher elevations near Bent Spring. All of these 

 springs are very small and apparently operational only during 

 times when livestock are in the area, thus providing an 

 unpredictable source of water for bats. 



CAVES 



Mystery Cave (T. 8 S., R. 28 E., Sec. 21, Carbon Co., MT; 

 elevation; 2384 m) is located near the south end of East Pryor 

 Mountain on BLM land in Douglas-fir forest. The entrance is 

 approximately 4 m wide and 2 m high. The cave extends over 500 m 

 in depth and possesses many interconnecting passages and rooms. 

 The cave temperature is approximately 2° C at 100 m from the 

 entrance, and the cave is very damp, with running water and small 

 pools present. Two searches of the cave on 14 and 2 3 August 

 revealed one Myotis lucifugus roosting, and the skeletal remains 

 of nine Myotis spp. Bat droppings were found throughout the 

 cave. The total of 120 bats captured in two nights of netting 

 (on 23 August and 4 September using one 5.5 m and one 9 m net) as 

 they flew from the cave's entrance indicates that the cave serves 

 as a major roosting site for bats. Many bats were observed 

 avoiding the nets, and many that became entangled in the nets 

 escaped before they could be removed, indicating that a 

 considerably larger number of bats were in the cave than were 

 actually captured. While few bats were observed roosting in the 

 cave during the day, some species of bats (e.g. Myotis volans and 



TABLE 10. — Bats Captured at Mystery Cave. 

 Species Males Females Total 



Myotis lucifugus 62 7 69 



Myotis ciliolabrum 1 - 1 



Myotis volans 27 - 27 



Myotis evotis 19 4 23 



Total 109 11 120 



12 



