Silver-haired Bat (Lasionycteris noctivagans) 



Description: This bat can be distinguished from all other bats in the Northern Rocky Mountains 

 by its distinctive coloration. The dorsal pelage is long, blackish brown, and "frosted" 

 with silvery white. Membranes are blackish brown, ears are short (12-17 mm), rounded, 

 and naked. The dorsal surface of the uropatagium is furred. Weighs 8-12 g. 



Distribution: Occurs throughout much of the United States and southern Canada north to 

 southeastern Alaska and south to northern Mexico. 



Habitat and Habits: Found in a variety of forested habitats, sometimes in open country 



associated with stands of frees; preferably near ponds and sfreams. Few summer roosts 

 have been described, but probable sites are behind bark or in free cavities. This bat is 

 more common in buildings in autumn during migration. Hibemacula include free 

 cavities, rock crevices and buildings, and infrequently in mines or caves. Most 

 individuals probably migrate out of the area (Izor 1979), but winter records exist for 

 British Columbia (Nagorsen er a/. 1993). In the Pacific Northwest, summer roosts are 

 probably most abundant in old growth forests (Perkins and Cross 1988, Thomas 1988). 

 This species is solitary, so it is rarely found in groups with more than 3-4 individuals. 

 Mating occurs in autumn, and the young are usually bom in June. Volant yoimg and 

 lactating females were caught in mid- July in Carter County, Montana (Jones et al. 1973). 

 This species emerges early in the evening to forage around sfreet lights, among frees, and 

 around standing water in a slow leisurely pattern low over the groimd. In 1994-1995 this 

 species was detected on the Kootenai National Forest at one site in July, 23 sites in 

 Augxist, and 23 sites in September (Appendix 3). 



Status: A fairly common summer resident in coniferous forest habitat throughout Montana 

 (Hofftnann and Pattie 1968), locally common in Carter County, Montana (Jones et al. 

 1 973), and probably common in Glacier National Park (Lechleitner 1 967). Most 

 individuals probably migrate out of the region in autumn. Seven of 1 13 bats captured by 

 Roemer (1994) were this species; it has been recorded from all Forest Districts 

 (Appendix 4). This species is present in the Idaho panhandle (Groves and Marks 1985). 

 The silver-haired bat is not listed by any federal agency. 

 Natural Heritage Program rank: G5; S4. 



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