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Western Small-footed Myotis {Myoiis ciliolabrum; formerly M leibii ciliolabrum) 



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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 



B projecting from the ankle which supports the uropatagium). 



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

 Mexico. 

 I 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 



I clay banks, and may use spaces tmder 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 Coimty in late Jime 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(1994) captured a lactating female on 1 September on the Libby District. 

 Status: Widespread, but with few records for Montana (Hofftnann and Pattie 1968, Hoffinaim et 

 al. 1969); appears to be fairly common in Carter and Carbon Counties ( Jones et al. 



11973, Worthington 1991). In western Montana, there are records from Mineral, 

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

 Columbia and Lethbridge, Alberta (van Zyll de Jong 1985). Seven of 1 13 bats captured 

 m^ 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 and 1 995 surveys, this species may have been present at sites where 



I Myotis sp. was detected (most species of Myotis are not easily distinguishable with bat 



detectors). The western small-footed myotis is not listed by any federal agency. 

 Natural Heritage Program rank: G5; S4. 



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