Indiana Bat Telemetry Investigations in PA-2006
Butchkoski, C.*, Turner, G. Pennsylvania Game Commission
In April 2006, a spring migration study was conducted on a female Indiana bat (Myotis sodalis) exiting the Glen Lyon abandoned anthracite coalmine subsidence in Luzerne County. Initially 2 Luzerne County abandoned anthracite-mining sites were planned for trapping - the privately owned Glen Lyon Mine and the Shickshinny Mine located on State Game Lands 260. Once trapping began, the Glen Lyon site became the focus due to manpower needs in processing the large captures there. Trapping occurred on 12 April (both sites) and 13 April resulting in captures of 3,103 bats: 3,013 little browns (Myotis lucifugus); 85 northern long-eared (Myotis septentrionalis); 1 Indiana bat; and 4 big brown bats (Eptesicus fuscus). The single Indiana bat (7g) was captured the first evening (12 April), banded using an orange celluloid band with the inscription 101PA, induced into torpor, and held for release the next evening in hopes that more female Indiana bats would be captured the second night. The second evening (13 April) resulted in no Indiana bat captures. Bat number 101PA was then radio-tagged, released, and intensively followed with aircraft and ground support, arriving at her summer habitat in Berks County during the early morning of 16 April, 90 km from the hibernaculum's in Luzerne County. When surveyors were confident she had settled in the area, 5 nights of intensive triangulation telemetry were conducted resulting in a minimum convex polygon (MCP) of 20.78 hectares using 64 foraging telemetry points. During this 5-day period she used 3 different shagbark hickory (Carya ovata) trees. On 17 July 2006 the summer habitat found was mist netted resulting in captures of 3 Indiana bats which were: A 8.1 g, post-lact. female, weighing 8.1 g; a juvenile non-reproductive male, 6.1g; and lactating female, 7.5 g. The heavier female (8.1 g) was banded (15PA), and radio-tagged to monitor habitat utilization. She used 3 different foraging/activity areas. Two roost trees were located, both of which were shagbark hickories. Emergence counts indicate that this bat was roosting alone during this time period.
On 19 September 2006 a male Indiana bat (8.4 g) was banded (17PA) and radio-tagged during the fall swarm at an abandoned limestone mine in Armstrong County. Upon release (01:30, 20 Sept.) the animal traveled ~9 miles northwest to a staging/foraging area. During 6 nights of monitoring, it visited the mine once (after capture) and returned to the staging/foraging area again that same night. Day roosts used included an occupied building attic and dead red maple trees (Acer rubrum) with exfoliating bark. Emergence counts indicated this bat was roosting alone.
New Jersey Indiana Bat Spring Migration from the Mt. Hope and Hibernia Mines
Chenger, John. Bat Conservation and Management, Inc.
A total of ten bats were fitted with transmitters and released with hopes of finding one summer maternity roost. BCM obtained five Indiana bat samples from each of two hibernaculum's, the Mt. Hope and Hibernia mines, near Dover, New Jersey. As each bat was released, ground observers closely monitored the migration behavior for up to several hours. One Mt. Hope bat was followed completely on the ground to an initial day roost. The remaining nine bats were initially lost at varying distances from the release points. During this initial phase of the project, eight of the eight (8) bats were ultimately recovered using a combination of coordinated ground and air radio telemetry. Each known bat location was field checked on a daily basis. Bats tended to switch roosts but never abandoned an area for the life of the transmitter. A total of twenty-one (21) day roosts were identified at distances ranging from 12.5 to 18 miles (20-29 km) from the hibernacula. Four significant roosts were discovered containing more than 30 individuals. Large tracts of land were systematically searched multiple times in an effort to locate the remaining bats. Approximately 800 linear miles (1,288 km) were searched by air and car encompassing 1,734 square miles (4,492 square km). Meanwhile, bats were monitored nightly and core foraging areas were observed for six of the eight initial bats.
Starting twenty days into the project on May 4, an effort was made to capture additional bats at new roosts or in newly discovered foraging areas. Three trap sites produced thirty-five (35) additional Indiana bats, including thirty which were captured emerging from a private single family home. A selection of five Indiana bats from these sites were radio tracked for at least up to twenty-two days. Bats tended to switch roosts and one may have abandoned the area, as it could not be recovered. Night observations identified core foraging areas for the remaining four bats. All of the foraging areas were within 3.5 miles (5.6 km) of the roost areas. The four tracked bats used thirteen (13) different roosts between May 4-25, 2006.
This project demonstrates that a small number of migrating bats can be successfully tracked using a team of coordinated ground observers coupled with daylight air searches. The ground team provided night observations, detailed bat behavior, and initial migration direction. The ground team's observations were used to specifically target aerial searches aiding with the efficient recovery of day roosts.
Common Sources of Radio Interference Can Severely Limit Telemetry System Performance.
Herzog, Carl. NY DEC
In favorable conditions, it is possible to detect a typical bat telemetry transmitter from a distance of at least 4 to 5 miles when monitoring from aircraft. New York DEC's program for spring emergence tracking of migrating. Sodalis has intermittently experienced periods where system performance was substantially worse than that, requiring significantly greater effort to locate tagged animals than would have otherwise been necessary. An extensive investigation has revealed that the likely cause is radio interference from terrestrial commercial sources common to many urban areas. It is likely that other researchers applying wildlife telemetry have experienced similar problems, perhaps without realizing it. The proposed solution involves judicious transmitter frequency selection in combination with other equipment choices
Spring Migratory Behavior of Indiana Bats and Its Implications for Determining Summer Distribution.
Herzog, Carl. NY DEC
We tested the hypothesis that previously reproductive female Indiana bats, Myotis sodalis, quickly and accurately fly toward their spring roost sites upon emergence from the hibernaculum. We captured bats at the beginning of their migration and radio-tracked them using aircraft, determining their initial flight direction and comparing that to their eventual roost sites. In the absence of certain intervening obstacles, there is a strong correlation between the initial flight direction and the direction of the first located roost. En route tracking and measured flight speed (up to 24 kph) for migrating bats also support the notion that the route chosen was direct. Use of this method greatly reduces the effort needed to locate spring roost sites, a research priority for managers.
Indiana Bat (Myotis sodalist) Maternity Colonies in the Great Swamp National Wildlife Refuge of New Jersey.
In June-August 2006, bat surveys resulted in the capture of 40 Indiana bats, 26 of them reproductively active females, in the Great Swamp National Wildlife Refuge (GSNWR). Ten radio transmitters were attached to adult female Indiana bats (2 non-reproductive, 4 lactating, 4 post-lactating.) Thirty-nine roost trees were found in the vicinity of the GSNWR over the span of 66 bat days (i.e., 1 bat located for 1 day equals 1 bat day.) Three colonies were identified; no movement was detected by any bat between any of these colonies. Distances between roosts used by a focal bat ranged from 3 m to 2.7km (median * 67.5m.) Red maple (Acer rubrum) was the most common of the 7 species of tree used (23.1% of all trees, 22.7% of all bat days.) Roost trees had a mean diameter of 41.8cm and were 20.0m in height. This study is just the second to be conducted on the roosting ecology of Indiana bat maternity colonies in the northeast, and provides critical life history information useful for the conservation of this species.
Indiana Bat Foraging/Roosting Habitat on an Anthropogenic Landscape: a Mist Net and Radio-telemetry Study in Northwestern New York.
A private developer proposes to construct new townhouses on a small parcel in the Town of LeRay in Jefferson County, New York, approximately 6 miles from a major Indiana bat hibernaculum (Glen Park Cave). A woodlot of approximately 15 acres represents the only forested portion of the project area. Original construction plans involved removal of the woodlot; therefore, a two-site summer mist net survey was completed in August 2006. Twelve bats representing five species were captured, including one post-lactating female and three adult male Indiana bats. Radio-transmitters were attached to all four Indiana bats, which were tracked to a combined total of 18 diurnal roosts. Roosts were predominantly American elm (Ulmus Americana; 67 percent), however, six other species of live and dead trees were also used. No roosts were found directly in the project area. Two roosts were documented on the nearby property of Fort Drum.
Nighttime radio-telemetry studies were performed to determine the foraging activity of the Indiana bats. Triangulation data collected in the field were analyzed using LOAS. Bat activity areas were then calculated in ArcGIS using the adaptive kerneling method. Each bat included at least some portion of the project area within its collective activity area. Results revealed substantial use of the project area for foraging, specifically concentrated around the woodlot and linear wooded fencerows.
Although the client is still involved in informal USFWS coordination, the project scope and layout have evolved to incorporate new bat-friendly ideas, while still accomplishing construction objectives.
Is capture in harp traps stressful to little brown bats (Myotis lucifugus)?
Reeder, DeeAnn *, Wasilko, Scott. Ostroski, Cassandra. Department of Biology, Bucknell University, Lewisburg, PA.
Most capture methods for free-ranging mammals presumably elicit an acute stress response, as measured by elevations in the hormones cortisol and/or corticosterone. These hormones play a role in energy balance and rise within a few minutes in response to stressful conditions in order to help the animal physiologically and behaviorally deal with the stressor. Harp traps offer a presumably minimally restrictive method for the capture of bats in that they do not physically restrain the animal (as do mist nets or other trapping methods for non-volant mammals). We were interested in determining whether capture in harp traps elicits a stress response in bats. Following capture at dusk, a plastic sheet was extended over the top of the bag of each harp trap and bats were held for a period of time ranging from 1 minute to 20 minutes. At the end of this time period, bats were hand captured from the bag and a small blood sample was immediately collected by lancing a vein in the uropatagium. Plasma was separated immediately with a battery operated field centrifuge and frozen until analysis for hormones via enzymoimmunoassay. Results will be presented at the meeting.
How to donate bats or tissue samples for permanent archiving and genetic analyses
Simmons, Nancy B.*, Department of Mammalogy, American Museum of Natural History, New York, NY 10024
Tissue samples and dead bats collected in the field (including those found during surveys of mortality at wind farm sites) offer a unique resource for investigating population genetics and migratory habits of bats at local, regional, and even continental scales. To facilitate this work and provide a permanent home for specimens piling up in freezers, The American Museum of Natural History has set up a program for accepting donations of dead bats and/or portions of bats collected around the USA. All that we require is (1) copies of permits indicating that the specimens were acquired legally, (2) data on where and when they were collected, (3) the specimens themselves, and (4) title to the specimens so that we may provide samples to qualified researchers for scientific study. Frozen bats, dried carcasses, whole or partial skeletons, and tissue samples (e.g., wing punches) are all acceptable. We will provide tissue sample tubes for anyone interested in collecting tissue samples; otherwise it is probably easier to donate whole animals. AMNH staff will process incoming specimens and preserve them in an appropriate fashion depending upon nature of the sample (taxon, degree of decomposition, whole or partial specimen, etc.). Tissue samples will be deposited in our state-of -the-art cryo collections. All samples will be made broadly available to the scientific community for research. Donated samples will join the over 270,000 mammal specimens already in our collections and available through our website (http://research.amnh.org/mammalogy/index.php). To make the process of donating bat samples easy, in January we will launch a website providing instructions and outlining the goals of genetic studies now underway to assess the effects of wind farm mortalities on bat populations in North America. This website can be found at http://research.amnh.org/mammalogy/batgenetics.
Radio Telemetry Studies of the Small-footed Bat (Myotis leibii) in Pendleton County, West Virginia.
Stihler, Craig W.* WV Division of Natural Resources, Elkins, WV.
Little is known of the life history of Myotis leibii, one of the rarest bats in the eastern United States. Previous mist net surveys demonstrated that M. leibii, including reproductively active females, could be captured on North Fork Mountain, Pendleton County, WV. Thus, a radio telemetry study was initiated to obtain information on roost sites and, to a lesser extent, foraging habitats. M. leibii were radio tracked in either June or July of 1999, 2002, 2004, 2005, and 2006. A total of 12 adult bats (males and pregnant, lactating, post-lactating, and non-reproductive females) were tagging using eyelash adhesive to attach transmitters between the scapulae. Twenty-five roosts were identified, and all were in rock outcroppings or talus. Eight roosts were in extensive cliffs; the exact location of three of these roosts could not be determined. Seventeen roosts were located in talus, most commonly under slabs of rock. Talus roosts were usually in narrow fissures between rocks, perhaps providing some protection from timber rattlesnakes (Crotalus horridus) and Allegheny wood rats (Neotoma magister) which also inhabit these areas. Most roosts received full or nearly full solar exposure. Roosts that were shaded were used more often by females than males. Roost switching was noted for both male and female bats. Only one bat, a lactating female, was observed roosting with other M. leibii (two on one day and three on another). At night, the bats foraged within 2.5 km of their day roosts. Foraging areas were mostly forested, although there were small areas of grassy and old field habitats. The forest was largely dominated by Quercus spp. with scattered small patches of forest dominated by Pinus virgininana.
Evaluation of the Program SCAN'R for Sorting Ultrasonic Recordings of Bat Vocalizations.
Williams, Shannon M.*, Wolbert, Stacy J. and Whidden, Howard P. Department of Biological Sciences, East Stroudsburg University, East Stroudsburg, PA.
Demand for alternative energy sources has led to explosive development of wind farms in many parts of the country. However, wind farms may pose a serious threat to bat populations. Acoustic monitoring of bat vocalizations is an important tool for assessing bat activity and the potential for bat mortality. However, ultrasonic detectors can sometimes record thousands of files each night, many of which are insect calls or environmental noise. Sorting through these files manually to identify bat calls is an enormous task and may limit the usefulness of acoustic monitoring. The new program SCAN'R (Binary Acoustic Technology) was designed to filter through these files and detect bat vocalizations. We assessed the performance of SCAN'R through close examination of almost 12,000 files recorded during acoustic monitoring. Files were sorted both by SCAN'R and a single experienced researcher and the results compared. Both techniques identified over 5,000 bat calls; SCAN'R picked up over 99% of the calls identified manually. The researcher picked up 31 calls that SCAN'R missed; these were typically weak calls surrounded by abundant background noise. However, SCAN'R picked up 11 calls that the researcher missed. SCAN'R appears to be a very effective tool for sorting large numbers of ultrasonic recordings.
Bat Activity in Relation to Temperature and Elevation.
Wolbert, Stacy *, Whidden, Howard P. Skirta, Eugenia and Turner, Greg. Department of Biological Sciences and Department of Mathematics, East Stroudsburg University, East Stroudsburg, PA, Pennsylvania Game Commission
A major source of alternative energy is wind power, and wind farms are currently being constructed at many sites in the eastern United States. While wind farms do provide an alternative form of energy, there is concern over their impacts on birds and bats. To better understand the role of temperature and elevation in bat mortality associated with wind farms, we sampled bat activity along an elevational gradient at 3 study areas in northeastern Pennsylvania. At each study area, bat activity was sampled with an AR125 acoustic detection system (Binary Acoustic Technology) at elevations of 1100', 1500', and 1900'. Each study area was sampled once a week. Temperature data were obtained from a Hobo data logger permanently installed at each of the 9 sampling sites. During 20 weeks of sampling, we recorded over 50,000 total bat passes. A weighted least-squares regression model was highly significant (p<0.001) with an r2 = 0.996. Standardized partial regression coefficients for hour, temperature, and elevation predictors were negative whereas date and location predictors were positive. We found no evidence that temperature inversions lead to increased bat activity along ridge tops.
Battling Bad Bat Searcher Efficiency: A New Mortality Survey Technique Using Nets.
Zellner, Andrew S. *, Whidden, Howard P. and Turner, Greg. Department of Biological Sciences and Pennsylvania Game Commission
The proliferation of wind farms along ridges of the Appalachians has raised concerns about bat mortality resulting from collisions with turbines. Assessment of this mortality has traditionally relied on mortality survey techniques that involve observers walking transects beneath turbines, noting carcass numbers and locations. However, several studies have shown that these current mortality surveys often suffer from poor searcher efficiencies. We are testing a new protocol for estimating turbine mortality that uses bird netting to catch impacted bats and birds. The netting will be placed horizontally at the base of turbines and should allow observers to quickly and comprehensively note all carcasses. Our proposed design relies on stratified random sampling for the placement of the netting, with several nets (14' x 100') below each turbine. To assess the effectiveness of the netting, observers, following traditional protocols, will walk comparable transects directly parallel and adjacent to the nets. We welcome any comments or suggestions about this design.
Regional Bat Capture Database.
Craddock, Melissa* and Eric Britzke.
The Southeastern Bat Diversity Network and Northeast Bat Working Group launched the Bat Capture Database to serve as a repository for all information gathered on bats in the eastern United States. The Database is accessible through www.sbdn.org and www.nebwg.org .