Hoary Bat {Lasiurus cinereus) 



Description: Can be distinguished from other bats by a combination of its large size (20-35 g) 

 and distinctive coloration. Dorsal pelage varies from yellowish brown to mahogany, 

 frosted with silver (imparting a "hoary" appearance). Hairs on the neck are longer than 

 those on the back, forming a slight "ruff." The wings are furred outward to the level of 

 the elbows, and the dorsal surface of the uropatagium is covered with dense ftir. There is 

 a yellowish white patch on each shoulder and a cream-colored spot near the wrist. Ears 

 are short (1 7-20 mm) and broad, and the calcar is moderately keeled. 



Distribution: Widespread across southern Canada south through the United States to northern 

 South America. 



Habitat and Habits: Occurs in many places during migration, but found in wooded habitats 

 during the breeding season. This species has not been found wintering in the region 

 (Nagorsen et al. 1993) although there is a winter record from western Washington 

 (Perkins et al. 1990); arrives in this region in June (Findley and Jones 1964). Day roosts 

 (about 3-5 m above ground) are mostly in trees, well-covered with vegetation above and 

 open below; apparently both deciduous and coniferous frees are used. Enters caves, 

 mines, and houses only rarely. Solitary or in small family groups during summer, 

 although larger aggregations may form during migration. Mating may take place before 

 migration or on the wintering grounds; females are pregnant by the time they migrate 

 north. Lactating females and volant young have been collected in July in the Long Pines 

 and Ekalaka Hills of Carter County, Montana (Jones et al. 1973). This species emerges 

 later in the evening than other species and is a swift flyer; it flies low, occasionally 

 impaling itself on barbed-wire fences. This bat regularly emits a chattering during flight 

 that is audible to the human ear. Usually found at lower elevations; summer roosts may 

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

 1994-1995 this species was detected at six sites in August and seven in September 

 (Appendix 3). 



Status: Hoffinaim and Pattie (1968) indicated that there are relatively few records for Montana, 

 and the species is hypothetical for Glacier National Park (Lechleitner 1967). It is, 

 however, a common summer resident in Carter County (Jones et al. 1973), and 

 Worthington (1991) captured several in southern Carbon County. Present in the Idaho 

 panhandle (Groves and Marks 1985). In 1994-1995, this species was recorded from all 

 Districts (Appendix 4). The Hoary Bat is not listed by any federal agency. 



Natural Heritage Program rank: G5; S4 



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