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Key words: bats, hibernacula, Montana, white-nose syndrome, winter
Management agencies require information on which species of bats remain in their jurisdiction during winter, including where they occur and in what numbers, particularly in light of the threat posed by white-nose syndrome, an infection caused by the fungus Geomyces destructans (Frick and others 2010; Blehert and others 2011). This is a necessary prerequisite for developing informed management and conservation guidelines for mitigating or eliminating on-going human disturbance at hibernacula and addressing the potential impacts of white-nose syndrome. Hibernating bats are especially vulnerable to winter arousal caused by human disturbance or the fungal infection associated with white-nose syndrome because bats have little ability to replenish fat reserves prior to spring emergence, and could starve if aroused unexpectedly from winter torpor (Thomas and others 1990; Thomas 1995; Frick and others 2010; Wilder and others 2011).
A compilation of winter bat records for Montana has not been available, the majority being specimens archived in museum collections or observations reported in unpublished documents. Inspection of mines and caves for hibernating bats in Montana has been limited. Thus, an organized and comprehensive survey of potential and known hibernacula in Montana has not been undertaken. Only a few of the several hundred workings surveyed included internal inspections, and but a minor fraction of these were entered during winter. Similarly, only a small percentage of the approximately 375 caves in Montana (Campbell 1978; J Ballensky, pers. comm.) have been examined during winter for the presence of bats. The most comprehensive winter survey of mines and caves has been in the Pryor Mountains in Carbon County (Madson and Hanson 1992), and only a single hibernaculum, Azure Cave in Phillips County, has been the focus of even moderate monitoring (Hendricks and others 2000). My primary objective for this paper, therefore, was to compile winter records of bats in Montana and identify their hibernacula, using available information. A compilation of winter records of bats will provide a basis for directing limited resources toward the protection of wintering bats in the state. A secondary objective was to compare patterns in Montana with adjacent areas to increase knowledge of winter bat ecology and distributions in this region of North America.
I define winter as the 6-mo period...