Bat survey along the Norris-Madison Junction Road corridor, Yellowstone National Park, Wyoming, 1999

LA <J$H (^ # u rr^u -$

Bat Survey Along the

Norris-Madison Junction

Road Corridor*

Yellowstone National Park,

Wyoming, 1999

A Report to:

National Park Service

P.O. Box 168

Yellowstone National Park, Wyoming 82190

Submitted by:
Paul Hendricks

May, 2000

/ YrT~ MONTANA

\y% Natural Heritage

^ub Program

Montana State Library

3 0864 1004 3985 3

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2000 Montana Natural Heritage Program

This document should be cited as follows:

Hendricks. P. 2UU0.Bat survey along the Noms-Madison Junction Road corridor. Yellowstone National Park.
Wyoming. 1999. Montana Natural Heritage Program Helena. MT. 15 pp.

ABSTRACT

An assessment of bat presence was conducted along the Norris-Madison Junction Road
corridor in Yellowstone National Park, Wyoming during 20-25 September 1999 Twenty-three
sites were monitored for bat activity, 21 sites were monitored overnight with electronic bat
detectors, and two sites were mist-netted for 2.0-2.5 hr after sunset. Five bridges (including one
just outside of the primary road corridor study area) were inspected for evidence of use by bats
(droppings or roosting individuals), and one additional elevated wooden road structure spanning
the outflow at a thermal feature was inspected for similar bat spoor One undeveloped thermal
area uas checked for bat spoor around boulders because the area is a known maternity site by an
unidentified bat species

Bats were recorded at 17 of 21 sites monitored with bat detectors, equipment malfunction
occurred at one site Species tentatively identified included Western Long-eared Myotis (Myotis
evotis) at 3 sites. Big Brown Bat (Eptesicusfuscus) at 3 sites, and Silver-haired Bat
(Lasionycteris noctivagans) at 5 sites Unknown bat species were recorded at 1 1 sites,
unidentified Myotis at 10 sites, and indistinguishable Big Brown/Silver-haired bat at 1 1 sites.
The amount of bat activity (number of recorded passes) was relatively low at the majority of sites
where bats were detected, ranging from 1-40 passes Twelve or fewer passes were recorded at
1 2 of 1 7 sites. 20 or more passes were recorded at the remaining 5 sites where bats were
detected

Two species of unidentified bats (one Myotis and one larger species) were observed
foraging at crown level among lodgepole pines at the Norris Campground (B Loop and entrance
area) between 19 40-21 15 MDT A few bats were observed at the two mist-netting sites, but
only one bat was captured, a male Little Brown Myotis (A/, lucifugus) along the Gibbon Ri\ci
below the Tuff Cliffs picnic area Bats observed at the second netting site (a small pond) were
either Big Brown or Silver-haired bats

Three of six bridges or bridge-like structures had evidence of bat use Three of four
bridges with steel beams and concrete or stone pilings had concentrations of bat droppings on
their undersides The wooden structure at Beryl Springs and the concrete bridge spanning the
Gibbon River at Madison Junction are probably used little if at all as a roost site by bats.

ACKNOWLEDGMENTS

This project was conceived and promoted by Roy Renken (Yellowstone National
Park) to supplement the scant information on bats in the park, especially along the highway
corridors. Roy supported the current effort in all aspects, and his interest, foresight and
enthusiasm are greatly appreciated. Thanks also to Roy Renken and Bob Proctor (Royal Society
for the Protection of Birds; Nethybridge, Scotland) for participating in the most productive
evening of mist-netting bats The study presented in this report was conducted under Research
Authorization Permit Number 5024.

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

Figure 1. Sites 1-7 along the Norris-Madison Junction Road corridor, Yellowstone National
Park, surveyed for bats in September 1999. Base Map from USGS 7.5' topographic quadrangle
"Norris Junction, Wyoming" 1986 Provisional Edition

Figure 2. Sites 8-12 along the Norris-Madison Junction Road corridor, Yellowstone National
Park, surveyed for bats in September 1999 B1-B3 are bridges inspected for bat sign. The "X"
is the site in the Geyser Springs Group of the Gibbon Geyser Basin where bat sign was found.
Base Map from USGS 7.5' topographic quadrangle "Norris Junction, Wyoming" 1986
Provisional Edition.

Figure 3. Sites 13-16 along the Norns-Madison Junction Road corridor, Yellowstone National
Park, surveyed for bats in September 1999. Base Map from USGS 7.5' topographic quadrangle
"Madison Junction, Wyoming" 1986 Provisional Edition.

Figure 4. Sites 17-23 along the Norris-Madison Junction Road corridor, Yellowstone National
Park, surveyed for bats in September 1999. B4 is a bridge inspected for bat sign. Base Map
from USGS 7.5' topographic quadrangle "Madison Junction, Wyoming" 1986 Provisional
Edition.

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1. .°-

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before dusk facing over water bodies or meadows, out over cliff faces, under or near bridges, or
down forest corridors and left in place overnight. An attempt was made to set out four or five
detector units each night. Recorded calls were analyzed on an IBM compatible PC using
ANABAT II zero-crossings analysis interface module (ZCAIM) and software.

Assignment of vocalizations to a particular species of bat was achieved by matching
time-frequency structure of field recordings with a reference set of calls obtained from captured
individuals and published descriptions of vocalizations (e.g., Fenton et al. 1983, O'Farrell 1997).
However, bat species can show significant variation in call structure (Betts 1998, Barclay 1999),
and we did not actively track and record flying bats (O'Farrell et al. 1999) to maximize quality
and quantity of diagnostic sequences. Furthermore, some units recorded bats flying near
potential roosts, such as cliffs or bridge structures. Roost-exit calls and calls in high
environmental clutter tend to be fragmentary, lacking diagnostic features necessary for species
identification (O'Farrell 1999). Therefore, all species-level identifications based on recorded
vocalizations are considered tentative where made in this study

Mvotis designations (as a group) were assigned to recordings with vocalizations of short
duration (< 3 msec) with a relatively linear, perpendicular call pattern. Where call sequences
were assigned toM evotis the sweep pattern ranged from a maximum 75 kFIz to a minimum of
30 kHz. Otherwise all were classified Myotis species. Calls with a bilinear (extreme curvilinear)
pattern were tentatively assigned to a non-Myotis species or classified as unknown bat. Passes
with call fragments were also designated unknown bat if no associated calls allowed finer
resolution. Bilinear call sequences were assigned to Eptesicusfuscus if a continuous frequency
tail fell within the range of 33-28 kHz with duration of the narrow band component of 1-3 msec,
and the maximum frequency extended to 45-50 kHz This could result in confusion with
Lasionycteris noctivagans (Betts 1998) because of significant overlap in call structure.
Maximum frequency of the latter species is about 40 kHz with a narrow band component lasting
3-5 msec, and calls with these characteristics were assigned to this species. However, in the
majority of cases these two species were not distinguished by the recorded calls.

Number of "passes" (defined here as a distinct vocalization with at least a 1 sec gap
between prior and following vocalizations) was recorded as a measure of relative activity at each
site. At one site equipment malfunctioned prematurely, and at another site with recorded activity
the recorder malfunctioned during the night Therefore, relative activity as presented here is
useful primarily as an index with variable degrees of error.

Capture of bats was attempted using 50-denier mist nets of various lengths (most often
2.8 and 6 m) and set in a variety of arrays across and along water bodies at two sites Nets
typically were operated for 2.0-2.5 hours (dusk until 21:30). Captured bats were identified with
aid of keys in van Zyll de Jong (1985) or Nagorsen and Brigham (1993). Individuals were
sexed, aged, measured (forearm, weight), reproductive status noted, then released.

The undersides of all bridges spanning the Gibbon River (n = 5, including one just
outside the primary study area) and a section of elevated road on a wooden structure at a thermal
site were inspected for evidence of use by bats. Areas most likely to provide roosting sites
included steel I-beam girders near any cross structure, and the spaces between longitudinal spans
and pilings. Bat sign most often included accumulated droppings (easily distinguishable from
rodent droppings) and sometimes staining of surfaces above potential roosting sites.

A visit was made to one thermal area off of the highway to inspect the undersides of
boulders for roosting bats or evidence of roosting activity (presence of bat droppings). This

10

thermal area (the Geyser Springs Group of the Gibbon Geyser Basin) has been a maternity site
for an unidentified species of Myotis in previous years (S Martinez personal communication)

RESULTS

Twenty-three sites (Figs 1-4, Table 1 ) were surveyed for bats using bat detectors (n = 21 )
or mist-nets (n = 2) In addition, five bridges (one near Norris Campground outside the stud)
area) crossing the Gibbon River and one elevated wooded road structure crossing a thermal
feature were inspected for bat use, and one thermal area was checked for sign of roosting bats
(see Figs 2 and 4)

Bat detector Survey Sites Bats were recorded at 17 (81°o) of 21 sites where bat detectors
were deployed (Table 1 ) Of the four sites with no detected activity, equipment failed at one. At
the sites where bats were detected, the majority ( 12 of 17) recorded low levels of activity ( 12 or
fewer passes) Activity at the remaining five sites ranged from 20-40 passes The vast majority
(> 90°o) of recorded passes occurred between 19:30-22 30 MDT at all sites

Bats of unknown identity were detected at 1 1 sites and undifferentiated Myotis were
detected at 10 sites These two categories represented 151 (72 6° o) of 208 total passes recorded
The remaining 57 passes were identified as Western Long-eared Myotis (A/, evotis): 8 passes at
three sites. Big Brown Bat {Eptesicusfuscus) 1 1 passes at three sites. Silver-haired Bat
[Lasionycteris noctivagans) 13 passes at five sites, undifferentiated Big Browa'Silver-haired
bat 25 passes at 1 1 sites Four of five sites with the most activity (20 or more passes) were
down river from Gibbon Falls, bat activity in the Norris area was relatively widespread but at
low intensity Not surprisingly, greatest activity was at water sources

Mtst-net Survey Sites Bat activity at the two sites where mist-nets were deployed was
low No bats were captured at the first site (*6, see Table 1 ), a small pond near a service road at
Gibbon Meadows However, a bat was observed flying along the road corridor nearby at crown
height, first at 19 45 with the last often passes at 20 35 (the nets were folded at 21 30) This
species was either a Big Brown or Silver-haired bat, based on size and the sound of the converted
vocalizations

At the second netting site (#19. bank of Gibbon River with a small backwater of calm
water below Tuff Cliffs), bats were first detected at 19:52 and continued activity at very low
levels nearby until nets were folded (21 30) Thirteen total passes were noted in two hours of
netting One Little Brown Myotis (A/, lucifugus) was captured at 20 05 when it came down to
drink from the pocket of calm water It was a mature scrotal male (right forearm length = 38 2
mm. weight =8.5g)

Bridges Four bridges spanning the Gibbon River in the Norris-Madison Junction road
corridor were checked for sign of bat use The first three bridges are built with steel I-beams
across stone or concrete pilings, the bridge at Madison Junction is solid concrete A fifth bridge.
near \orns Campground, was essentially constructed like bridges B1-B3 An elevated section o\'
road on wooden ties and pilings at Beryl Springs was also inspected

No bat droppings were noted under the span of the first bridge ( B 1 ) south o\~ Norris.
although this bridge appears to offer some suitable roosting sites Scattered bat droppings were
noted on stone/concrete pilings and the steel beams of bridges B2 and B3 at the upstream ends
Two sizes of droppings were found at bridge B3. indicating that more than one bat species has
roosted under this span The concrete span ( B4 ) at Madison Junction offers no roost sites for

ll

TABLE 1. Sites surveyed for bat activity, 20-25 September 1999 along the Norris-Madison
Junction Road corridor in Yellowstone National Park, Wyoming. Primary survey methods used
at these sites were bat detectors (D) or mist-nets (N).

Site

#

Site Name Date Method

Bats Detected1 (# passes)

1

Tantalus Creek (S of highway)

24 Sept

D

None

2

Slope above Gray Lakes

24 Sept

D

MYSP(l)

3

SW end of Elk Park

24 Sept

D

EPFU/LANO (1)

4

Gibbon River Rapids

24 Sept

D

None

5

Gibbon Meadows service road

20 Sept

D

EPFLVLANO(l)

6

Gibbon Meadows service road pond

2 1 Sept

N

EPFU/LANO (10 distant passes; no captures)

7

Gibbon Meadows. N end on nver

20 Sept

D

UNKN(2). MYSP(10)

8

Gibbon Meadows. S end cliffs

20 Sept

D

MYSP (2). LANO ( 1 ). EPFU/LANO (3)

9

Near Bridge B 1 (Gibbon Canyon) ! 2 1 Sept

D

MYSP ( 1 ). EPFU/LANO ( 1 )

10

Beryl Springs > 24 Sept

D

None (equipment malfunction)

11

Near Bridge B2 (Gibbon Canyon)

21 Sept

D

UNKN ( 1 ). MYSP (2). EPFU/LANO (1)

12

Near Bridge B3 (Gibbon Canyon)

21 Sept

D

UNKN (14). MYSP (4). EPFU (4). LANO (1)

13

Secret Vallev Creek, near mouth

21 Sept

D

UNKN(l)

14

N of Gibbon Falls, W side cliff

22 Sept

D

LANO (9)

15

Gibbon Falls picnic area (W end)

22 Sept

D

UNKN (4)

16

Gibbon River bottom . at stone wall

23 Sept

D

UNKN (5). MYSP (29). EPFU/LANO (2)

17

Base of Tuff Cliffs

23 Sept

D

UNKN (2). MYSP (5). MYEV (1).
EPFU/LANO (1)

18

Gibbon River at Tuff Cliffs

22 Sept.

D

UNKN (15). MYSP ( 14). MYEV (6). EPFU
(2). LANO (1). EPFU/LANO (2)

19

Gibbon River at Tuff Cliffs

24 Sept

N

MYLU (1 male). 12 passes by at least 2 species

20

Terrace Spring

23 Sept.

D

None

21

Purple Mountain trailhead

22 Sept

D

UNKN (2). MYEV ( 1 ). EPFU/LANO (2)

22

Madison Junction marshes/ponds

23 Sept.

D

UNKN (2). MYSP (4). EPFU (5). LANO (1).
EPFU/LANO (8)

23

Madison Junction sewage ponds 23 Sept D

UNKN (31). EPFU/LANO (3); equip problems

1 UNKN (unknown bat species). MYSP (Myotis species). MYEV (Myotis evotis). MYLU {Myotis lucifugus). EPFU
(Eptesicus fuscus). LANO (Lasionyteris noctivagans). EPFU/LANO (either E. fuscus or L. noctivagans).

12

bats, and no sign of bat use was found The largest quantity of bat guano was found under the
downstream end of the bridge near Norris Campground No sign was found on or under the
wooden road structure at Beryl Springs, a thermal area that passes under the road span

Undeveloped thermal areas The Geyser Springs Group of the Norris Geyser Basin is a
known maternity site for an undetermined species of Myotis (S Martinez personal
communication) This site was visited to search for roosting bats or signs of use under the
boulders in the thermal area (where the roost is located) Numerous boulders or exposed rocks
imbedded in the area were checked for bats and bat sign Scattered droppings were found
beneath 2-3 boulders near the site marked "X" in Fig. 2.

Nun is Campground Bat activity in the campground (B Loop and entrance area) was
observed during the evening of 23 September The first pass by a bat was noted at 19 40 At
least three individuals of two species were observed foraging near treetop and lower crown
height (10-13 m): a species of Myotis and the larger Big-Brown or Silver-haired bat Foraging
rate was about 3 passes/min from 20: 10-20:43, about 1 pass/min from 20:45-21 00, and about
0.5 pass/min from 21 00-21 15, when observations terminated

DISCISSION

At least four species of bats were recorded during the survey in the Norns-Madison
Junction area Western Long-eared Myotis, Little Brown Myotis, Big Brown Bat. Silver-haired
bat Activity levels were relatively low at all sites, but this could be partly a result of the late
date of the surveys. Activity in the Norris and Gibbon Meadows area was lower than that
recorded at the lower-elevation area below Gibbon Falls to Madison Junction This did not seem
to be related entirely to differences in over-night temperatures.

Foraging activity by bats at and over thermal features was low. as Martinez (1999) also
noted Perhaps thermal areas are not as attractive to the variety and abundance of aerial insects
that are fed upon by bats as are some non-thermal sites Nevertheless, maternity colonies of at
least two bat species (Townsend's Big-eared Bat. and a species of Myotis) have been
documented in thermal areas in YNP (Martinez 1999, personal communication) Similar
maternity sites have been reported elsewhere in western North America (eg Nagorsen and
Bngham 1993, West and Swain 1999) The thermal areas of YNP could support matermtv
colonies of several bat species and merit closer survey effort by qualified biologists and park
personnel

Bats use a number of man-made structures in YNP for maternity roosts (Bogan and
Geluso 1999) Bridges may also be used for this purpose, but are more likely to be used as night
roosts Bridges throughout YNP deserve closer monitoring to determine when thev are being
used, by bow many individuals and species, and for what purposes Bridges could provide
important roosting habitat to some species in areas receiving considerable human impact As
bridges are repaired or replaced, they could be designed to be "bat friendly" by providing the
undersides with tight or secure spaces for roosting, usually on exposed steel I-beams or where
these are secured close to the pilings supporting the bridge The bridge design at Madison
Junction is distinctlv unsuitable for bats, and the elevated road span at Beryl Springs is perhaps
too low and accessible to predator attack to be very attractive to bats

\n is already obvious, more inventory effort is needed in YNP to determine which
species of bats are present and when, what habitat features are especially attractive to them, and

13

what human activities within the park are most likely to have the greatest impact on the bat
populations present. Sites in most need of identification are maternity roosts and hibernacula, as
these are very sensitive to human disturbance. Future systematic inventories should make use of
multiple survey techniques (see Thomas and West 1989, O'Farrell and Gannon 1999) to assure
the most complete assessment of the bat fauna.

LITERATURE CITED

Barclay, R. M. R. 1999. Bats are not birds — a cautionary note on using echolocation calls to
identify bats: a comment. Journal of Mammalogy 80:290-296.

Betts, B. J. 1998. Effects of interindividual variation in echolocation calls on identification of
Big Brown and Silver-haired bats. Journal of Wildlife Management 62:1003-1010.

Bogan, M. A., and K. Geluso. 1999 Bat roosts and historic structures on National Park Service
lands in the Rocky Mountain region. US G S Midcontinent Ecological Science Center,
Albuquerque, NM. Unpublished report. 25 pp

Clark, T. W., and M. R. Stromberg. 1987. Mammals in Wyoming. University of Kansas

Museum of Natural History, Public Education Series No. 10. Lawrence, KS. 3 14 pp

Fenton, M. B., H. G Merriam, and G L Holroyd. 1983. Bats of Kootenay, Glacier, and Mount
Revelstoke national parks in Canada: identification by echolocation calls, distribution,
and biology. Canadian Journal of Zoology 61 :2503-2508

Martinez, S. 1999. Evaluation of selected bat habitat sites along the Mammoth-Norris Grand

Loop road corridor, Yellowstone National Park, Wyoming, 1997-1998. Montana Natural
Heritage Program, Helena, MT Unpublished report. 16 pp.

Nagorsen, D. W , and R. M. Brigham. 1993. The bats of British Columbia University of
British Columbia Press, Vancouver, British Columbia. 164 pp.

Nesser, J. A., G L. Ford, C. L. Maynard, and D. S. Page-Dumroese. 1997. Ecological units of
the Northern Region: subsections. General Technical Report INT-GTR-369. Ogden,
UT: USDA Forest Service, Intermountain Research Station. 88 pp.

O'Farrell, M. J. 1997. Use of echolocation calls for the identification c e-flying bats
Transactions of the Western Section of The Wildlife Society 33.

O'Farrell, M. J. 1999. Blind test for ability to discriminate vocal signatures of the Little Brown
Bat Myotis lucifugus and the Indiana Bat Myotis sodahs. Bat Research News 40:44-48.

O'Farrell, M. J., and W L Gannon 1999. A comparison of acoustic versus capture techniques
for the inventory of bats. Journal of Mammalogy 80:24-30.

14

O'Farrell, M J,B VV Miller, and W L Gannon 1999 Qualitative identification of free-flying
bats using the Anabat detector Journal of Mammalogy 80 1 1-23

Thomas. D W , and S. D West 1989 Sampling methods for bats Gen Tech Rep PNW-
GTR-243 Portland, OR U.S. Dept Agn . Forest Serv , Pacific Northwest Research
Station 20 pp (Ruggiero, L F , and A B Carey, tech eds. Wildlife-habitat
relationships sampling procedures for Pacific Northwest vertebrates).

van Zyll de Jong, C. G. 1985. Handbook of Canadian mammals 2 Bats National Museum of
Natural Sciences Ottawa, Ontario 212 pp

West. E W . and U. Swain 1999 Surface activity and structure of a hydrothermally-heated
maternity colony of the Little Brown Bat, Myotic lucifugus, in Alaska Canadian Field-
Naturalist 113 425-429.

15