INTRODUCTION 



Little information is currently available on the bats inhabiting Yellowstone National Park 

 (YNP) The most recent comprehensive account of the mammals of Wyoming (Clark and 

 Stromberg 1987) provides records of only three bat species in the park Western Long-eared 

 Myotis {Myotis evotis), Little Brown Myotis (Myotis lucifugus), and Townsend's Big-eared Bat 

 (( 'orynorhinus townsendii) Six additional species were predicted to occur in YNP To date, at 

 least one of these, the Silver-haired Bat {Lasionycteris noctivagatis), has now been confirmed 

 with specimen documentation (R Renken personal communication) 



In the last five years at least two investigations of bats have occurred within limited areas 

 of YNP Bogan and Geluso (1999) studied summer roosts (especially maternity roosts) of bats in 

 human-made structures at several sites Little Brown Myotis was the only bat species thev 

 documented in YNP during their study An inventory of bat use of the Mammoth-Norris Grand 

 Loop road corridor by Martinez ( 1999), using electronic bat detectors and mist-nets, reported six 

 bat species including Fringed Myotis (A/, thysanodes), Big Brown Bat (Eptesicus fuscus), and 

 Hoary Bat (Lasiurus cinereus ) With the exception of Townsend's Big-eared Bat, none of these 

 species were captured or identified visually, so species identifications should be considered 

 tentative (see Study Area and Methods for a discussion of using bat vocalizations for species 

 identifications) 



As pan of a prelimmarv inventory and assessment of bat distribution in YNP the survey 

 reported here compliments previous inventory efforts In the current survey the focus of the 

 inventory was the section of highway and adjacent landscape between Norris and Madison 

 Junction in the northwest portion of the park, a continuation to the south of the previous road 

 corridor survey of Martinez (1999) Primary objectives were to identify areas of bat activitv and 

 provide species determinations where possible 



STUDY AREA AND METHODS 



The portion of highway in YNP covered by the bat survey reported here (Norris to 

 Madison Junction, see Fig 1-4) falls within the Yellowstone Volcanic Plateau of the 

 Yellowstone Highlands Section (Nesser et al 1997), and is characterized by a cold continental 

 climate with warm dry summers and cold dry winters There are a number of thermal features in 

 the area, adding to the diversity of habitats dominated by extensive stands of conifers Sites 

 Mirveved during the inventory ranged in elevation from 6800-7600 ft (2073-23 16 m) Most sites 

 were in terrain dominated by lodgepole pine [Pinus contorta) 



Fieldwork was conducted from 20-25 September 1999 Overnight low ambient 

 temperatures were measured with a Taylor maximum-minimum thermometer Daily minimum 

 temperatures ranged from 26°F on 21 and 22 September to 39°F on 24 September Dailv 

 temperature maxima were about 65-75°F 



Bat detectors (AN \B \ I II. Titley Electronics. Ballina. Australia) or mist nets were 

 deployed near water, cliffs or other outcrops, open corridors in forest, forest-meadow edges, and 

 bridges where bats might be likely to forage Multiple survey techniques are recommended for 

 more complete and accurate inventory (O'Farrell and Gannon 1999) Detector units (consisting 

 of an ultrasound detector, timer tape-driver, and a voice-activated cassette tape recorder) were set 



