Night-Roosting Behaviors for the Northern Long- Eared Myotis (Myotis septentrionalis) Under a Bridge Revealed by Time-Lapse Photography Author(s): Keith Geluso, Emma C. Keele, Nicole M. Pauley, Isabella R. Gomez, and Simon P. Tye Source: The American Midland Naturalist, 179(2):287-293. Published By: University of Notre Dame https://doi.org/10.1674/0003-0031-179.2.287 URL: http://www.bioone.org/doi/full/10.1674/0003-0031-179.2.287 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Am. Midl. Nat. (2018) 179:287–293 Notes and Discussion Piece Night-Roosting Behaviors for the Northern Long-Eared Myotis (Myotis septentrionalis) Under a Bridge Revealed by Time-Lapse Photography ABSTRACT.—The northern long-eared myotis (Myotis septentrionalis) occurs across much of eastern North America and is listed as federally threatened in the United States due to pervasive population declines. Limited data are available about roosting behaviors for this imperiled species. We report on night-roosting behaviors for the northern long-eared myotis under a bridge in northwestern Nebraska. Grooming, short visits, and feeding were the most frequently observed behaviors. Grooming, inactivity, and nursing had the longest durations, albeit all averaged ,15 min per event. We also documented movement and urination infrequently. Prey manipulation associated with feeding was a frequent behavior and consisted of individuals facing upward or downward, culling wings, elytra, and legs of large prey items. When facing upward wing and tail membranes formed a cup against the abutment wall that likely limited loss of prey. Individuals used the bridge throughout the night but roosted most frequently at 4 and 8 h after sunset (00:15 and 04:15 h, respectively), with early morning activity dominated by feeding/prey manipulation. Our study showed night roosts were used frequently for many reasons, especially for grooming and consumption of large prey. Our observations represent the first description of night-roosting behaviors for the northern long-eared myotis. INTRODUCTION The northern long-eared myotis (Myotis septentrionalis) is an insectivorous bat occurring across much of eastern North America, ranging from the Atlantic coast to western Canada and parts of the Great Plains (Hall, 1981; Caceres and Barclay, 2000). The species was common throughout much of its distribution before onset and spread the fungus, Pseudogymnoascus destructans, associated with white-nose syndrome that has killed millions of bats of different species (USFWS, 2013, 2015). Pervasive population declines in eastern parts of its distribution led to the northern long-eared myotis being listed as federally threatened in the United States and as endangered in Canada (Turner et al., 2011; COSEWIC, 2013; Moosman et al., 2013; USFWS, 2015; Ingersoll et al., 2016; Reynolds et al., 2016). The northern long- eared myotis roosts in natural and artificial structures (Whitaker et al., 2006; Ormsbee et al., 2007; Stein and White, 2016); however, limited information is available regarding roosting behaviors, including in anthropogenic structures (Ormsbee et al., 2007). Night roosts serve many important functions for bats including, but not limited to, digestion, energy conservation, feeding, grooming, information transfer, protection from inclement weather or predators, and rest (Kunz, 1982; Ormsbee et al., 2007). Duration of night-roosting bouts vary by species (Ormsbee et al., 2007), and some species can spend up to 75% of their nocturnal activity period at night roosts (O’Shea and Vaughan, 1977). Frequency of night roosting depends on multiple factors, including reproductive status and time of year (Anthony et al., 1981; Barclay, 1982; Ormsbee et al., 2007). Understanding functions of night roosts in anthropogenic structures can benefit conservation efforts toward declining bat species (Ormsbee et al., 2007; Knight and Jones, 2009). Many bat species use anthropogenic structures, such as mines, buildings, and bridges, for night roosts (Ormsbee et al., 2007). The extent to which bats use bridges as night roosts and for what purposes remains unclear for many species (Lewis, 1994; Keeley and Tuttle, 1999; Adam and Hayes, 2000; Ormsbee et al., 2007). Moreover, relatively few studies have quantitatively examined the behaviors at night roosts for many temperate bat species in North America (Ormsbee et al., 2007). Herein we describe night-roosting behaviors of the northern long-eared myotis under a roadway bridge. Use of camera traps with time-lapse photography enabled us to discreetly document frequency and duration of behaviors, details rarely reported from night roosts. Understanding how and when the northern long-eared myotis uses anthropogenic structures will aid in conservation and management strategies, as interactions between this protected species and humans are inevitable. 287 288 THE AMERICAN MIDLAND NATURALIST 179(2) FIG. 1.—Underside of a small bridge in northern Sheridan County, Nebraska, where camera traps were placed to document night-roosting behaviors of the northern long-eared myotis (Myotis septentrionalis), July 2016. Night roosting was observed in semi- enclosed chambers at the top of both abutments between horizontal and vertical girders. Left and right photographs show chambers on the south and north abutments, respectively. White arrows indicate where individuals roosted on abutments METHODS We conducted this study at a bridge spanning Larrabee Creek, Sheridan County, in the Pine Ridge region of northwestern Nebraska from 22 to 30 July 2016 (Fig. 1; as the bat species in this study is protected, the specific locality data are available from the corresponding author upon request). The segment of creek by the bridge was generally 2.5 m wide and ,0.5 m deep, bordered by a narrow ribbon of deciduous trees that consisted predominantly of plains cottonwood (Populus deltoides), green ash (Fraxinus pennsylvanica), and willows (Salix). East of the bridge for 0.7 km was a pasture without livestock, therefore tall grasses, forbs, and hydrophytes were abundant on this side of the creek. Horses had heavily grazed vegetation along the creek for about 50 m west of the bridge, and those reaches were more open for bats to drink and fly. The surrounding landscape transitioned to gradual hills and ridges dominated by ponderosa pine (Pinus ponderosa) intermixed with agricultural fields and rangelands for domestic livestock. The bridge was small, with a single span between abutments (Fig. 1). Exposed abutment surfaces under the bridge consisted of horizontally-stacked wooden timbers held in place by seven vertical steel I- beams below one horizontal I-beam. Heights of north and south abutments were about 2 m and 2.5 m above the ground, respectively. The bridge deck (9 3 9 m) was supported by seven steel girders, and its underside was covered by corrugated steel sheet metal. These structural elements resulted in six semi- enclosed areas under the deck, hereafter called chambers. Each chamber was about 1.5 m in width between horizontal girders and 8 m in length between the two bridge abutments. We identified bats as the northern long-eared myotis based on length of ears and size compared to other species captured in the area. In addition we placed forearms bands only on northern long-eared myotis in the region. We observed a number of bats, both solitary and in groups, with forearm bands in photographs to confirm identifications. Individuals were identified as recently volant based on their gray coloration and darker appearance in photographs (see Swier, 2003). These age characteristics originally were learned by capturing bats along an adjacent part of the stream near the bridge. Three camera traps (PC800 HyperFire Professional, Semi-Covert, Reconyx Inc., Holmen, Wisconsin) were deployed in three different chambers under the bridge to document night-roosting behaviors of the northern long-eared myotis with time-lapse photography. No bats were present during daylight hours when installing cameras and downloading images. One camera faced the south abutment and two 2018 NOTES AND DISCUSSION PIECE 289 faced the north abutment (Fig. 1). Cameras were placed in chambers with the greatest quantity of fresh guano and prey remnants. We recovered a sample of prey remnants from below roosting surfaces. We identified prey remnants to order and, if possible, to family and measured remnant lengths. Time-lapse and motion-triggered photographs were collected for nine nights beginning on the evening of 22 July and ending the early morning of 30 July 2016. One camera lost power for about 1.5 nights. Cameras used infrared lighting to illuminate