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Biological Assessment for DMG Permit Renewals McClave Canyon & Munger Canyon Mines
<br />(Fitzgerald et al. 1994). Centers of population density appear to occur around Big Bend, Texas
<br />(Ellison et al. 2004). No breeding records exist for Colorado, but individual wanderers may be
<br />expected across the region in appropriate habitat, which is pinyon-juniper woodlands, arid
<br />grasslands, and semi-desert shrublands (Fitzgerald et al. 1994) below about 8,500 feet in
<br />elevation (Ellison et al. 2004). The population status of the big free-tailed bat within the
<br />assessment areas is unknown. Little is known of the species' natural history. Big free-tailed bats
<br />are seasonally migratory, roost in crevices on cliff faces or in buildings, and forage mostly on
<br />large moths after dark (Fitzgerald et al. 1994). Threats to the species have not been identified,
<br />but general, widespread threats to bats likely affect big free-tailed bats: use of insecticides or
<br />pesticides and overgrazing in foraging areas, and disturbances to roosts such as rock blasting
<br />(Ellison et al. 2004).
<br />Fringed mvotis (S). This bat is apparently uncommon in Colorado, inhabiting ponderosa pine
<br />woodlands, oakbrush, greasewood, and saltbush shrublands (Fitzgerald et al. 1994). Xeric
<br />woodlands (pinyon-juniper or oak) to elevations of 7,500 feet appear to be the most commonly
<br />used habitat type in the western U.S. (Ellison et al. 2004). Its population status within the
<br />assessment areas is unknown. Caves, crevices in cliff faces, mines, and buildings are used as
<br />both day and night roosts (Fitzgerald et al. 1994; Ellison et al. 2004). The fringed myotis is a
<br />localized migratory species and a colonial rooster, with colonies ranging from 10 to 20,000
<br />individuals (Ellison et al. 2004). This species forages close to the plant canopy, often gleaning
<br />insects and other invertebrates off foliage (Fitzgerald et al. 1994). Roosting bats are thought to
<br />be easily disturbed by human presence. Other threats include pesticide and insecticide
<br />spraying, livestock grazing, renewed mining at historic sites where roosting colonies have
<br />become established, vegetation or building conversions, and toxic material impoundments
<br />(Ellison et al. 2004).
<br />Spotted bat (S). The spotted bat is apparently uncommon in Colorado (Fitzgerald et al. 1994).
<br />Its distribution is patchy throughout its range in the western U.S. and central Mexico, where it is
<br />strongly associated with prominent rock features required for roosting (Ellison et al. 2004). Its
<br />ecology is poorly understood. The spotted bat is a solitary forager, feeding after midnight on
<br />moths, grasshoppers, Mormon crickets, and katydids. Specimens have been captured in a
<br />broad range of habitats, from semi-desert shrublands to pinyon-juniper woodlands to montane
<br />ponderosa pine forests. Its population status within the assessment areas is unknown. Because
<br />of the remoteness of their roost sites, threats to this species are thought to be mainly
<br />recreational rock-climbing, impoundment of reservoirs in canyon situations, and large-scale
<br />control of Mormon crickets and grasshoppers with insecticides (Ellison et al. 2004).
<br />Townsend's big-eared bat (S, SC). This bat occurs across western and southern Colorado,
<br />occupying semi-desert shrublands, pinyon-juniper woodlands, and montane woodlands to
<br />elevations of about 9,500 feet, and is closely associated with caves, abandoned mines, or
<br />abandoned buildings for winter hibernacula and day roosts (Fitzgerald et al. 1994). During
<br />summer, single individuals may roost in cliff cracks or tree hollows. Much of their foraging
<br />occurs after midnight over water and over vegetation at water's edge, where they often glean
<br />insects directly off foliage. Primary prey appears to be the moths. The population status of this
<br />bat in western Colorado or within the assessment areas is unknown. Principal threats to this
<br />species are disturbances to hibernacula in caves or mines. The species appears to be easily
<br />disturbed and may abandon roost sites after a single human visitation (Ellison et al. 2004).
<br />Insecticide spraying is thought to affect prey base (Ellison et al. 2004).
<br />Yuma mvotis (S). This bat is probably fairly common in the semi-arid canyon and mesa country
<br />of western Colorado and occurs in a variety of habitats near riparian areas (Fitzgerald et al.
<br />2004) with perennial sources of water (Ellison et al. 2004). It is a crepuscular forager, and
<br />March 27, 2006 14 Rare Earth Science,
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