Myotis leibii (Eastern Small-footed Myotis) Roosting in Buildings
of Great Smoky Mountains National Park, Tennessee
Kirstin E. Fagan, Emma V. Willcox, Riley F. Bernard, and William H. Stiver
Southeastern Naturalist, Volume 15, Issue 2 (2016): N23–N27
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2016 Southeastern Naturalist Notes Vol. 15, No. 2
K.E. Fagan, E.V. Willcox, R.F. Bernard, and W.H. Stiver
Myotis leibii (Eastern Small-footed Myotis) Roosting in Buildings
of Great Smoky Mountains National Park, Tennessee
Kirstin E. Fagan1,*, Emma V. Willcox1, Riley F. Bernard1, 2, and William H. Stiver2
Abstract - Myotis leibii (Eastern Small-footed Myotis) are infrequently encountered across their
range, and as a result, little is known about their summer roosting ecology. This species is not federally
protected, but receives legal protection in many states, including Tennessee. Additional information
on the species, particularly its summer roosting ecology, is needed to inform appropriate management
and conservation planning. While conducting a summer survey of multiple bat species using buildings
as roosts in Great Smoky Mountains National Park, we discovered Eastern Small-footed Myotis roosting
in 3 historic buildings on the northwest slope of Mount LeConte. At least 1 building contained a
maternity colony. Humans used all 3 buildings on a daily basis.
Myotis leibii (Audubon and Bachman) (Eastern Small-footed Myotis) is considered rare
across most of its range (Best and Jennings 1997). The species is infrequently encountered;
thus, its summer roosting ecology is poorly understood. The fungal disease white-nose
syndrome was first documented in North America in 2006. Since then, populations of some
species of Myotis have undergone significant declines across the eastern US (Frick et al.
2010, Moosman et al. 2013, Turner et al. 2011). In 2013, the US Fish and Wildlife Service
found that available data on Eastern Small-footed Myotis did not warrant federal listing
under the Endangered Species Act (USFWS 2013). However, this species receives statelevel
protection in some states, including Tennessee, where it is listed as a species of special
concern and deemed in need of research and management. Research to provide information
on the distribution and habitat needs of the Eastern Small-footed Myotis is a top priority
(TWRA 2015). More specifically, managers in Tennessee and other southeastern states need
comprehensive and accurate information on the roosting behaviors of this species; information
about maternity roosts is particularly lacking.
During summer, crevices in rocky outcroppings, talus slopes, and small boulders with
high solar-exposure are considered preferred natural roosts for Eastern Small-footed Myotis
(Erdle and Hobson 2001, Johnson et al. 2011, Moosman et al. 2015, Tuttle and Heaney
1974), but the species is known to utilize anthropogenic surrogates, including bridges and
tunnels (Best and Jennings 1997, Johnson and Gates 2008, Thomson 2013). Published
observations of Eastern Small-footed Myotis using buildings as summer roosts, however,
are relatively uncommon. Among published records for the southeastern US, O’Keefe and
LaVoie (2010) discovered a maternity colony of ≥18 bats in an 85-y-old cabin at 1447 m
in elevation, on property of the Eastern Band of the Cherokee Nation in Swain County,
NC. Neuhauser (1971) published the first record of the species in Great Smoky Mountains
National Park (GRSM), and observed a single, non-reproductive adult female entering a
hiking cabin at 675 m in elevation in Greenbrier Cove, Sevier County, TN. In Mammoth
Cave National Park, KY, Barbour (1963) reported a male of unknown age that had been
found dead in a campground restroom. In the northern regions of the species’ range, maternity
colonies have been found in buildings (Merritt 1987) and sliding doors of various
1Department of Forestry, Wildlife, and Fisheries, University of Tennessee, Knoxville, TN 37996.
2Great Smoky Mountains National Park, National Park Service, Gatlinburg, TN 37738. *Corresponding
author - ewillcox@utk.edu.
Manuscript Editor: Roger Perry
Notes of the Southeastern Naturalist, Issue 15/2, 2016
2016 Southeastern Naturalist Notes Vol. 15, No. 2
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K.E. Fagan, E.V. Willcox, R.F. Bernard, and W.H. Stiver
outbuildings (Harvey et al. 2001, Hitchcock 1955), in addition to natural roosts (Johnson et
al. 2011; Moosman et al. 2013, 2015).
From 15 May to 14 August 2015, we surveyed 145 buildings in GRSM (Tennessee and
North Carolina) as part of a broader study examining use of buildings by multiple bat species
during summer. When bats were located, we counted individuals and identified them
to species. We captured bats by hand if feasible, avoiding adult females with pups. If we
incidentally captured adult females with pups, we immediately returned them to the roost.
We recorded age, sex, reproductive status, mass (g), and forearm length (mm) for adults
and volant juveniles. We banded adults with individually numbered 2.4-mm split-ringaluminum
bands on their forearm (Porzana Ltd., East Sussex, UK). After processing, we
returned each bat to the roost. We assessed human activity and structural characteristics at
each building, including type, design, and construction; presence of human disturbance; and
ease of access by bats to the interior (i.e., airtight building or open windows and doors). We
placed Thermocron iButtons (Model DS1921, Maxim Integrated, San Jose, CA), wrapped
in a layer of 2-mm polystyrene to attenuate ultrasound emitted by the device, at roost sites
to record temperature to the nearest 0.1 °C at 60-min intervals .
While conducting our surveys, we observed Eastern Small-footed Myotis occupying 3
buildings in GRSM, 2 of which were classified as historic buildings. These buildings were
located within the LeConte Creek, Roaring Fork, and Baskin’s Creek watersheds on the
northwest slope of Mount LeConte, outside Gatlinburg, TN. Combined, these watersheds
cover 3914 ha of rocky upland terrain and are dissected by a single road that allows access
to National Park Service (NPS) buildings and others managed by NPS for cultural heritage
and tourism along the Roaring Fork Motor Nature Trail, including the 3 historic structures
mentioned above.
Building A was an 85-y-old, 2-story, 395.0-m2 (4252-ft2) structure with an irregular
floor plan (i.e., not rectangular), multiple perpendicular gables with dormers, a wrap-around
porch at the northeast corner, and a small, second-story back porch at the southwest corner.
The structure consisted of horizontally laid logs, masonry, partial wood-shingle siding, a
wood-shingled main roof, and a corrugated-tin porch roof. The interior was modern and
airtight. The building was used as an office and occupied daily by NPS personnel. It was
located with 5 other NPS buildings in a 1.32-ha clearing at an elevation of 601 m. Surrounding
habitat consisted of floodplain, oak–hickory, and hardwood cove forest.
We observed Eastern Small-footed Myotis at Building A on 5 occasions at 3 roosts. On the
northeast porch, 1 roost was in a rotting rafter (Fig. 1a), and a second roost was a few meters
away in a crevice between the roof and rafters (Fig. 1b). Due to the proximity of these 2 roosts,
we only placed one iButton to record temperature (daytime temperature = 23.7 °C ± 3.8 °C
[mean ± SD], nighttime temperature = 21.8 °C ± 2.1 °C). The third roost was on the floor joists
under the southwest porch (Fig. 1c; daytime temperature = 22.0 °C ± 2.4 °C, nighttime temperature
= 21.1 °C ± 1.7 °C). Prior to June 16, we noted fresh guano only under the southwest
porch. On 16 June, we observed 17 bats roosting on the northeast porch in the rotting rafter,
and we captured 4 lactating females, 1 female with an attached pup, and 4 volant juveniles. On
2 July, 3 July, and 8 July, we observed a total of 15 volant bats of unknown age at the northeast
and southwest porch roosts. On 11 August, we observed 2 volant bats in the crevice between
the rafters and roof of the northeast porch, 1 of which we captured and identified as an adult
non-reproductive female. Our observations suggest that Eastern Small-footed Myotis used
this roost location for most of the summer maternity period.
Building B was a 129-y-old, 2-story, 49.8-m2 (536-ft2) cabin, consisting of 2 rooms,
each with a fireplace connected to a central chimney, with a common wood-shingled gable
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K.E. Fagan, E.V. Willcox, R.F. Bernard, and W.H. Stiver
roof and a small attached room on the west side. It was constructed of logs covered by sawn
board panels on the interior and exterior, and was painted on the exterior. The doors were
permanently open; thus, the building was not airtight. The stairway that allowed access to
the attic was closed off, but we investigated the space using a flashlight through gaps around
the chimney. Building B was located in the center of a 0.08-ha clearing at 647 m elevation.
We observed Eastern Small-footed Bats at Building B on 2 occasions. On 8 July, we
captured 4 individuals roosting together on a ceiling beam in the northeast corner of the
south main room (daytime temperature = 23.0 °C ± 2.3 °C, nighttime temperature = 22.1 °C
± 1.5 °C): 2 adult post-lactating females, 1 volant juvenile male, and 1 volant juvenile female.
On 11 August, we captured 1 adult scrotal male Eastern Small-footed Bat and 1 adult
scrotal male Eptesicus fuscus (Beauvois) (Big Brown Bat) that were roosting 2 m apart on
the north-most ceiling beam of the north main room. This beam was similar in appearance
and structure to the one described above (Fig. 1d; no temperature data available).
Figure 1. Roosts found in buildings in the Twin Creeks area of Great Smoky Mountain National Park.
(a) Eastern Small-footed Myotis roost in rotting rafter on the northeast porch of Building A. (b) Eastern
Small-footed Myotis roost in crevice between the roof and rafters on the northeast porch of Building
A; (c) Eastern Small-footed Myotis roost on floor joist under the southwest porch of Building A;
(d) Big Brown Bat roosting 2 m right of Eastern Small-footed Myotis roost on ceiling beam in Building
B; and (e) Eastern Small-footed Myotis roost on ceiling beam in front of a fireplace in Building C.
2016 Southeastern Naturalist Notes Vol. 15, No. 2
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K.E. Fagan, E.V. Willcox, R.F. Bernard, and W.H. Stiver
Building C was a 135-y-old, 1.5-story, 42.3-m2 (455-ft2) structure, consisting of 2 rooms
that each had a fireplace and were connected by a central breezeway, all under a woodshingled
gable roof. There was no interior or exterior wall covering except some limited
paneling at the gable ends. The building was not airtight because the doors and windows
were permanently open. The attic space above each room was reachable only by ladder
through an access hole. Building C was at an elevation of 699 m in the center of a 0.13-ha
clearing, which also contained a similarly constructed 0.09-m2 (114-ft2) structure where we
detected no bats. Building C was located 600 m north of Building B, and tourists visited
both buildings every day during the summer months. Vegetation in proximity of both cabins
consisted of hardwood acid cove, chestnut–oak, and mixed-hardwo od–pine forest.
We found 1 dead adult female Eastern Small-footed Myotis at Building C on 8 July.
Examination suggested she was lactating or post-lactating. We found the bat on the ground
directly adjacent to the northwest end of the breezeway. We observed no obvious signs of
fracture or other trauma, and due to the absence of rigor mortis and lack of fly eggs or larvae,
suspect the individual had died recently. We collected this bat and stored it at the University
of Tennessee, Knoxville, TN. Though we only detected 1 bat at this building, we observed
guano inside the cabin throughout the summer, particularly under beams in the southeast
room in front of the fireplace (Fig. 1e; daytime temperature = 21.6 °C ± 2.8 °C, nighttime
temperature = 20.6 °C ± 2.1 °C).
We found evidence that Eastern Small-Footed Myotis used all 3 buildings throughout
the summer, with at least 1 confirmed as a maternity colony. We first found lactating
females with attached young, as well as some volant juveniles, in the buildings in
mid-June. Our findings agree with those of Best and Jennings (1997), who reported
parturition in May or June, and Johnson et al. (2011), who noted the first capture of a lactating
female of the species on 2 June. However, Moosman et al. (2015) did not observe
lactating females until late June, and reported lactating females and volant juveniles into
mid-July; females we captured during mid-July were post-lactating. We caught a scrotal
male Eastern Small-footed Myotis in mid-August slightly earlier than Moosman et al.
(2015), who did not report scrotal males until early September.
We observed lactating and post-lactating female and juvenile Eastern Small-footed
Myotis roosting in GRSM historic buildings despite considerable human disturbance and
an abundance of rocky terrain in the immediate area that appeared suitable for roosting.
Although buildings may provide benefits, including reduced predation and preferred microclimatic
conditions (Lausen and Barclay 2006), the buildings where we observed bats
were used by humans each day, often for prolonged periods. Studies examining the use of
buildings by other bat species indicate human disturbance may negatively affect survival
rates (López-Roig and Serra-Cobo 2014), and bats may select structures with low human
activity (De Boer et al. 2013, White 2004).
Further research is needed to avoid negatively impacting Eastern Small-footed Myotis
and understand their roosting preferences. Future work on this species should include
repeated surveys of buildings, intensive searching for natural roosts, investigation of the
costs and benefits of different roost locations, and exploration of roost fidelity and potential
maternity networks incorporating both buildings and natural roost sites. This knowledge
could be used to improve management of buildings to benefit these bats across the species
range, including timing of maintenance activities and, if necessary, restriction of human
access. Ultimately, these research results would allow managers to better balance bat conservation,
cultural resource preservation, and public health concerns, which are important
considerations in protected areas. When making management decisions regarding buildings
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K.E. Fagan, E.V. Willcox, R.F. Bernard, and W.H. Stiver
in forested areas, we suggest structures not yet surveyed for bats should be considered potential
bat roosts during the summer months.
Acknowledgments. This research was funded by the National Park Service. We would like to thank
Shelby Cotham and Michael Barnes for their help with fieldwork a nd data collection.
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