N15 2017 Northeastern Naturalist Notes Vol. 24, No. 2 Z.A. Hann, M.J. Hosler, and P.R. Moosman Jr. Roosting Habits of Two Lasiurus borealis (Eastern Red Bat) in the Blue Ridge Mountains of Virginia Zackary A. Hann1, Micah J. Hosler1, and Paul R. Moosman Jr.1,* Abstract - Lasiurus borealis (Eastern Red Bat), long considered a common species, is now experiencing population declines. Most studies of their roosting habits have reported that the species uses mature canopy trees. We radio-tracked 2 adult male Eastern Red Bats to their roost trees in the Blue Ridge Mountains of Virginia in June of 2012. Both bats roosted in a different tree each day, but spent 3–5 days roosting in groups of nearby trees before making larger movements out of the study area. Characteristics of roost trees differed markedly between bats. One bat roosted in Castanea dentata (American Chestnut) and Quercus rubra (Red Oak) saplings in early-successional habitat; the other roosted in mature Quercus spp. (oaks) in closed-canopy forest. Most roost trees and nearby trees were shorter and smaller diameter than those reported in previous studies. Our results suggest Eastern Red Bats have relatively broad roosting habits that include use of both early- and late-successional habitat. Introduction. The population status of migratory tree bats (those in the genera Lasiurus and Lasionycteris) is of increasing concern due to the long-term effects of habitat destruction and fatalities at wind-turbine facilities (Arnett et al. 2008, Kunz et al. 2007, Kurta and Teramino 1992). Lasiurus borealis Müller (Eastern Red Bat) is considered widespread and abundant, but the species also has recently experienced increased rates of mortality associated with wind-energy facilities (Arnett et al. 2008, Barbour and Davis 1969, Shump and Shump 1982, Whitaker and Hamilton 1998). It is unclear whether Eastern Red Bats are being significantly impacted by other factors because their ecology is poorly understood. The species has primarily been documented roosting in mature deciduous trees in several states including: Arkansas, Georgia, Illinois, Iowa, Kentucky, Maryland, Missouri, North Carolina, and South Carolina (Constantine 1966, Hutchinson and Lacki 2000, Limpert et al. 2005, Mager and Nelson 2001, Menzel et al. 1998, Mormann and Robbins 2005, O’Keefe et al. 2009, and Perry et al. 2007). Eastern Red Bats have been documented less often roosting in other vegetation, including large Pinus taeda L. (Loblolly Pine) in Mississippi, young deciduous trees in North Carolina, and grasses and Helianthus spp. L. (sunflowers) in Illinois (Downes 1964, Elmore et al. 2004, Mager and Nelson 2001, O’Keefe et al. 2009). Information about the roosting habits of Eastern Red Bats has not been published from other parts of their range, including Virginia. Observations. We documented roosts of 2 male Eastern Red Bats at a site in the Blue Ridge Mountains of Virginia and compared our observations to those of previous studies to improve understanding of geographic variation in roosting habits. We conducted field work from 28 May to 15 June 2012 at Sherando Lake Recreation Area (hereafter, Sherando), in the George Washington and Jefferson National Forests, in Augusta County, VA. Sherando hosts a 3-ha upper lake and a 10-ha lower lake, which are impoundments of South Fork Back Creek, a high-gradient stream in the Blue Ridge Mountains. Vegetation surrounding Sherando is mostly mature, closed-canopy, mixed-deciduous forest interspersed with relatively small (less than 10 ha) early-successional patches created by timber harvests (clear cuts) and wildfires. Elevations range from 561 m at the lower lake to 823 m at the top of the neighboring ridges. 1Department of Biology, 30 Maury Brook Hall, Virginia Military Institute, Lexington, VA 24450. *Corresponding author - moosmanpr@vmi.edu. Manuscript Editor: Hugh Broders Notes of the Northeastern Naturalist, Issue 24/2, 2017 2017 Northeastern Naturalist Notes Vol. 24, No. 2 N16 Z.A. Hann, M.J. Hosler, and P.R. Moosman Jr. We captured 3 adult male Eastern Red Bats by placing mist nets (6 m high x 9 m long) across the corridor formed by South Fork Back Creek at 2 sites that were 822 m apart. We captured the first bat (A) on 28 May and the remaining bats (B and C) on 7 June. We weighed bats to the nearest 0.25 g with a spring scale (Pesola, Baar, Switzerland) and recorded their age, sex, and reproductive condition. Age was determined by the amount of closure of the epiphyseal growth plates in the finger bones (Anthony and Kunz 1988). We marked each bat by placing a numbered aluminum band on the forearm (Porzana, Ltd., Birmingham, UK). After trimming fur from the area with scissors, we used bonding cement (Torbot Group, Inc., Cranston, RI) to attach a 0.37-g radio transmitter (weighing 3.0–3.5% of body mass; Type LB-2NT, Holohil Systems, ON, Canada) between the scapulae. Bats were released at the site of capture and we attempted to track each animal to its roost daily, beginning the day after capture, using a 3-element Yagi antenna and R1000 radio receiver (Communications Specialists, Inc., Orange, CA) and a handheld GPS unit with 3–5 m accuracy (eTrex, Garmin Ltd., Lenexa, KS) to record location. When we identified a roost tree, we searched for the bat using 10x binoculars and an 85-mm spotting scope (Victory, Zeiss, Oberkochen, Germany). At each roost location, we identified the species of tree, measured tree height and height of the bat’s position using a laser range-finding hypsometer (TruPulse, Laser Technology, Inc., Denver, CO), and measured tree diameter at breast height (dbh) to the nearest 0.1 cm. We measured each bat’s cardinal direction (to the nearest degree) with a magnetic compass and estimated its distance (to the nearest 0.1 m) from the trunk of the roost tree. We collected information about nearby trees using the point–quarter method, with the roost tree as the center of the plot, and recorded the species, height, and dbh of the nearest tree in each quadrant established along cardinal directions. Results are reported as mean ± se. We located 2 of the 3 bats that were radio-tagged. Bat A was first located on 30 May (2 days after release) on a gently sloping alluvial plain 4.2 km north of where it was captured. It roosted in a different tree in the same area each day for the next 5 days, until its signal was no longer detected. Trees used by Bat A included 3 Castanea dentata Marsh. (American Chesnut) and 2 Quercus rubra L. (Red Oak); all trees had a small dbh (5.5 ± 0.2 cm). These roosts were in a patch of forest that had been burned by wildfire (D. Wright, US Forest Service, George Washington and Jefferson National Forests, James River Ranger District, VA, pers. comm.) and was in early successional stages of regeneration, with dense cover of Rubus spp. L. (blackberry) and tree samplings less than 7 cm dbh. Mean distance between consecutive roosts for Bat A was 30 ± 4 m and mean elevation was 520 ± 0.4 m. The day after capture, Bat B was first tracked to a south-facing slope at 740 m elevation, in mature closed-canopy forest (precise location could not be determined) ~1.6 km west of where it was captured. Bat B apparently left the study area, and we could not detect its radio-signal for the next 4 days. We re-acquired its signal on 13 June and tracked the bat to the xeric south-facing crown of a ridge with closed-canopy forest, at ~663 m elevation, 2.2 km from the capture site and 3.4 km from its former roost. The bat roosted 2 more days in nearby trees, until its signal was lost on 16 June. The 3 trees used by Bat B were mature Quercus prinus L. (Chestnut Oak) 23.2 ± 0.6 cm in diameter. Mean distance between consecutive roosts of Bat B was 1223 ± 628 m and mean elevation was 681 ± 9.7 m. Both bats roosted an average of 7.2 ± 0.4 m from the ground (~60% of the total height of roost trees), and they were positioned 1.0 ± 0.1 m from the trunk on the southeast side of the trees (120 ± 18°). Nearby trees at the study site appeared to be of comparable height and diameter to roost trees (Table 1). Roost trees were composed of 37.5% Chestnut Oak, 37.5% American Chestnut, and 25% Red Oak, whereas composition of nearby trees was 27% N17 2017 Northeastern Naturalist Notes Vol. 24, No. 2 Z.A. Hann, M.J. Hosler, and P.R. Moosman Jr. Sassafras albidum Nuttall (Sassafras), 20% Chestnut Oak, 20% Nyssa sylvatica Marshall (Black Gum), 13% Quercus alba L. (White Oak), 13% Red Oak, and 7% American Chestnut. Discussion. Movement patterns of the bats we studied were similar to patterns reported in other studies. Bats switched roosts daily, but spent multiple days in an area before making larger movements to a different part of the forest. The roost trees that we were able to locate were 3.3 ± 0.2 km from the capture site, which is a distance that underestimates distances moved because both bats also made larger movements that prevented us from locating them. Other authors have reported similar patterns, but in some studies, roosts were used for multiple days (e.g., >2 days per roost reported by Hutchinson and Lacki 2000). We are not aware of any studies that have investigated what factors influence movement patterns of Eastern Red Bats. The difference in the types of roost trees used by the 2 bats we studied points to some breadth in behavior, which is also apparent when viewed in context with previous studies at other sites. Eastern Red Bats in other areas have roosted in trees of various sizes and species, but the bats we studied used some of the smallest trees that have been reported in the literature (Table 1). Only Mormann and Robbins (2007) documented roost trees that were smaller than those in our study. A greater number of studies have reported Eastern Red Bats using particularly large-diameter trees (e.g., >39 cm average dbh), including Hutchinson and Lacki (2000) in Kentucky, Menzel et al. (1998) in Georgia and South Carolina, and Limpert et al. (2005) in Maryland. Several studies have found that Eastern Red Bats select trees on the basis of species and size; depending on availability, tall, large-diameter deciduous trees are most often selected (Elmore et al. 2004, Hutchinson and Lacki 2000, Limpert et al. 2005, Menzel et al. 2000, Perry et al 2007). Sample sizes in our study were too small to warrant statistical hypothesistesting, but our results were similar to other studies of roosting habits of Eastern Red Bat in that we only observed bats roosting in deciduous trees. In contrast to other regions, average heights and dbh of roost trees in our study tended to be slightly smaller than those of nearby trees. This difference could have been influenced by the fact we had a small sample size and only observed male bats, but it also likely reflects geographic variation in age, structure, and composition of available forested habitat. Bat A’s use of American Chestnut saplings is a noteworthy example that supports this idea. Use of American Chestnut by Eastern Red Bats has only been reported once previously, in North Carolina (O’Keefe et al. 2009). Saplings of this species were common at our Table. 1. Comparison of roosting habits of Eastern Red Bats reported in published studies (± se). NR = values were not reported by the authors. . Roost site Roost tree Nearby tree State Height (m) Height (m) DBH (cm) Height (m) DBH (cm) Source VA 7.2 ± 0.4 12.1 ± 0.7 12.1 ± 1.2 12.7 ± 0.5 15.2 ± 0.6 Present study AR 11.9 ± 0.6 16.8 ± 0.5 26.1 ± 1.3 14.8 ± 0.5 21.7 ± 1.1 Perry et al. 2007A NC NR 16.9 ± 3.0 28.3 ± 6.1 NR NR O’Keefe et al. 2009 KY 16.5 ± 0.3 18.5 ± 0.3 40.8 ± 1.9 18.1 ± 0.1 36.9 ± 0.5 Hutchinson and Lacki 2000 GA, SC 15.3 ± 1.9 24.9 ± 1.0 37.8 ± 2.2 17.0 ± 0.5 22.5 ± 0.5 Menzel et al. 1998 MO 4.1B 10.4 ± 0.95 16.4B 10.8 ± 0.7 NR Mormann and Robbins 2007 MS NR NR 22.8 ± 3.8 NR NR Elmore et al. 2004 MD NR NR 42.0 ± 2.9 NR 37.9 ± 4.6 Limpert et al. 2005 AData shown are for male bats. BAuthors only reported mean values. 2017 Northeastern Naturalist Notes Vol. 24, No. 2 N18 Z.A. Hann, M.J. Hosler, and P.R. Moosman Jr. study site, in recently disturbed areas of forest where openings in the canopy have allowed vegetative regrowth of trees previously eliminated from the overstory by Cryphonectria parasitica (Murrill) Barr (Chestnut Blight). Furthermore, although use of such roosts has not been widely reported, instances of Eastern Red Bats roosting in other forms of relatively low-growing vegetation have been described in some studies (Downes 1964, Mager and Nelson 2001). From this perspective, our results are consistent with the broader behavioral repertoire of Eastern Red Bats that includes both the use of mature canopy trees and lowergrowing early successional vegetation. Acknowledgments. We thank M. Western for helping us in the field and the USDA Forest Service staff at Sherando Lake Recreation Area for facilitating our research. We also thank the journal’s staff and anonymous reviewers for their comments on earlier versions of this manuscript. Literature Cited Anthony, E.L.P. 1988. 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