2018 Northeastern Naturalist Notes Vol. 25, No. 3
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S.A. Fulton and L.E. Dodd
Acoustic Activity of Bats in Kentucky during the Total Solar
Eclipse of 2017
Shelby A. Fulton1,2 and Luke E. Dodd1,*
Abstract - We characterized patterns of bat activity outside primary hibernacula of Myotis bats at
Mammoth Cave National Park on the days preceding, concurrent with, and following the total solar
eclipse which occurred on 21 August 2017. Additionally, we documented nightly patterns of bat activity
for hydric habitats and forest corridors across Kentucky during a 7-d period encompassing the
eclipse. Our results suggest there was no diurnal bat activity occurring in response to the total solar
eclipse, and there was no clear evidence of altered nightly activity patterns. However, these observations
provide baseline data for future study of bat responses to eclipse events.
Bat-emergence patterns are inherently cyclical, but are subject to light disturbance. Experimental
manipulation of external lighting has been shown to result in delayed emergence
and reduced activity of numerous bat species (Stone et al. 2015). Considering the novelty
of such observations, our objective was to assess patterns of bat activity in the context
of the atypical light conditions imposed by a total solar eclipse occurring on 21 August
2017. Although total solar eclipses are rare, this event was conspicuous and widespread
in its impact as it traversed a wide swath of North America (NASA 2017a). Our acoustic
surveys during this eclipse incorporated data from 3 sites in Kentucky, located ~20, 115,
and 110 km, respectively, from the path of total occultation: Mammoth Cave National
Park in Edmonson County, Lower Howard’s Creek Nature and Heritage Preserve in Clark
County, and Floracliff Nature Sanctuary in Fayette County. These sites experienced 99.5%,
94.7%, and 94.9% solar occultation, respectively (NASA 2017b). During the hour of the
eclipse, ambient light at Mammoth Cave National Park decreased by ~80% (NPS 2017). In
contrast, ambient light decreased by ~30% in Madison County, adjacent to both Clark and
Fayette Counties (M. Ciocca, Eastern Kentucky University, Richmond, KY, unpubl. data).
We hypothesized that abnormal activity patterns would be more likely to occur at Mammoth
Cave National Park given its proximity to the path of total eclipse.
We conducted acoustic sampling of caves at Mammoth Cave National Park from 20
to 22 August 2017; the sampling interval represented 1 day prior to, the day of, and 1 day
following the eclipse. We deployed Song Meter SM3BAT Ultrasonic Recorders (Wildlife
Acoustics, Maynard, MA) that were active 24 h a day at a default sampling rate of 256 kHz
at the principal, gated entrances of Dixon Cave and Long Cave. These caves are Priority 1
hibernacula for Myotis sodalis Miller and Allen (Indiana Bat) (USFWS 2007) and, despite
the impact of White-nose Syndrome, continue to support thousands of bats throughout the
winter months (R. Toomey, Mammoth Cave National Park, KY, pers. comm.).
Additionally, we deployed 5 Song Meter SM2BAT+ Ultrasonic Monitors (Wildlife
Acoustics) on the landscape of Mammoth Cave National Park (37°11'13.2"N,
86°06'05.2"W), Floracliff Nature Sanctuary (37°54'10.1"N, 84°21'35.3"W), and Lower
Howard’s Creek Nature and Heritage Preserve (37°55'09.4"N, 84°16'25.4"W) from 18 to 24
August. The SM2BAT+ units were active from sunset to sunrise and recorded at a sampling
rate of 384 kHz; we chose detector locations to represent both forest corridors and hydric
1Department of Biological Sciences, Eastern Kentucky University, Richmond, KY 40475. 2Current
address - Office of Kentucky Nature Preserves, Kentucky Energy and Environment Cabinet, Frankfort,
KY 40601 *Corresponding author - luke.dodd@eku.edu.
Manuscript Editor: Hugh Broders
Notes of the Northeastern Naturalist, Issue 25/3, 2018
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2018 Northeastern Naturalist Notes Vol. 25, No. 3
S.A. Fulton and L.E. Dodd
habitats where we expected greater bat activity (Fulton et al. 2014). We employed Kaleidoscope
Pro analysis software (Version 3.1.4B) to quantify echolocation passes. Sensitivity
settings selected passes containing a minimum of 2 pulses ranging from 8 kHz to 120 kHz
in frequency and 2 ms to 500 ms in duration.
Nocturnal data from forested habitats displayed no clear trend in hourly bat activity
across nights (Table 1). Only 3 echolocation passes were recorded at cave entrances between
sunrise and sunset during our sample period, and none occurred during the eclipse.
However, we recorded an average of 529.7 and 2497.7 echolocation passes per 24-h day at
Dixon Cave and Long Cave, respectively, confirming bat presence on the landscape. While
historical reports of bat behavior during eclipse events are scarce, Wheeler et al. (1935)
observed several bats in flight during a total solar eclipse. In contrast, Krzanowski (1959)
observed no emergence during totality. Our observations suggest that bats in Kentucky did
not become active during the daylight hours of the eclipse. While our results do not fully
reconcile previous reports, these observations do provide a benchmark of acoustic activity
that may inform future studies of bat responses to infrequent meteorological events.
Acknowledgments. We thank R. Toomey and S. Thomas for helpful comments on earlier drafts of
this manuscript. Technical support was provided by S. Thomas and K. Gorman. We thank Mammoth
Cave National Park and the Kentucky State Nature Preserves Commission for land access. Financial
support was provided by the Joint Fire Sciences Program (Grant #14-1-05-22) and Eastern Kentucky
University Department of Biological Sciences.
Literature Cited
Fulton, S.A., L.E. Dodd, and L.K. Rieske. 2014. Riparian habitats are important to foraging bats in
the Bluegrass Region’s urban parks. Urban Naturalist 3:1–13.
Krzanowski, A. 1959. Behavior of bats during the total solar eclipse in Poland on June 30th, 1954.
Acta Theriologica 2:281–283.
National Aeronautics and Space Administration (NASA). 2017a. NASA Goddard Space Flight Center’s
eclipse website. Available online at https://eclipse.gsfc.nasa.gov/eclipse.html. Accessed 21
September 2017.
NASA. 2017b. Total solar eclipse interactive map. Available online at https://eclipse2017.nasa.gov/
sites/default/files/interactive_map/index.html. Accessed 21 September 2017.
National Park Service (NPS). 2017. National Park Service Gaseous Pollutant Monitoring Program
database. Available online at https://ard-request.air-resource.com/. Accessed 2 January 2018.
Stone, E.L., S. Harris, and G. Jones. 2015. Impacts of artificial lighting on bats: A review of challenges
and solutions. Mammalian Biology 80:213–219.
US Fish and Wildlife Service (USFWS). 2007. Indiana Bat (Myotis sodalis) draft recovery plan. First
revision. US Department of the Interior, Region 3, Fort Snelling, MN.
Table 1. Total number of echolocation passes recorded at Dennison Ferry (Edmonson County, KY),
Floracliff Nature Sanctuary (Fayette County, KY), and Lower Howard’s Creek Nature and Heritage
Preserve (Clark County, KY) from 18 to 24 August 2017. Detectors were operational from sunset to
sunrise. A total solar eclipse occurred in the afternoon hours of 21 August 2017.
Total Passes
Site 18 Aug 19 Aug 20 Aug 21 Aug 22 Aug 23 Aug 24 Aug
Mammoth Cave (Dennison Ferry) 3 0 1 0 0 145 71
Floracliff (Pond) 3 0 0 0 3 3 1
Floracliff (Road) 46 43 32 48 2 24 66
Lower Howard's Creek (Creek) 26 6 9 5 3 12 11
Lower Howard's Creek (Corridor) 8 8 2 5 3 1 8
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Wheeler, W.M., C.V. MacCoy, L. Griscom, G.M. Allen, and H.J. Coolidge. 1932. Observations of the
behavior of animals during the total solar eclipse of 31 August 1932. Proceedings of the American
Academy of Arts and Sciences 70:33–70.