Western Small-footed Myotis {Myotis ciliolabrnnr, formerly M. leibii ciliolabrum) 



Description: This is the smallest (3-7 g) bat in the area. Dorsal pelage is pale yellowish brown 

 to golden brown, contrasting with the blackish ears (13-15 mm) and membranes. The 

 most notable characteristic other than small size is the strongly-keeled calcar (the spur 

 projecting from the ankle which supports the uropatagium). 



Distribution: Ranges over much of western North America from southern Canada to northern 

 Mexico. 



Habitat and Habits: Appears to prefer more arid habitats, where it is associated with cliffs, talus, 

 clay buttes, and steep riverbanks. Roosts in crevices in buildings, trees, rock faces, and 

 clay banks, and may use spaces under and between talus and boulders. Hibemacula 

 include caves and abandoned mines in central Montana (Swenson 1970) and Idaho 

 (Center 1986). Tends to become active at dusk and forages low along cliffs and rocky 

 slopes rather than over water. Little information is available on reproduction. One of six 

 females collected in Carter County in late June to early July carried an embryo (Jones et 

 al. 1973), and a lactating female was collected on 18 July (Lampe et al. 1974). Roemer 

 ( 1 994) captured a lactating female on 1 September on the Libby District. 



Status: Widespread, but with few records for Montana (Hoffmann and Pattie 1968. Hoffmann et 

 al. 1 969); appears to be fairly common in Carter and Carbon Counties ( Jones et al. 

 1973, Worthington 1991). In western Montana, there are records from Mineral, 

 Missoula, and Ravalli Counties (Hoffmann et al. 1969); found at Osoyoos Lake, British 

 Columbia and Lethbridge, Alberta (van Zyll de Jong 1 985). Seven of 1 1 3 bats captured 

 by Roemer (1994) on the Kootenai National Forest were this species; it has been 

 recorded from the Cabinet, Libby, and Rexford Districts (Appendix 4). While not noted 

 during the 1 994 survey, this species may have been present at sites where Myotis sp. was 

 detected (most species o{ Myotis are not easily distinguishable with bat detectors). The 

 Western Small-footed Myotis is a U. S. Fish and Wildlife Service candidate (C2) species 

 for federal listing. 



Natural Heritage Program rank: G5; S4. 



