Bat Activity Surveillance Monitoring at Neda Mine Hibernaculum

J. Paul White, Erin Crain, and Owen Boyle

Wisconsin Department of Natural Resources, Bureau of Natural Heritage Conservation,

White-Nose Syndrome (WNS) has spread across 26 states and 5 Canadian provinces. The fungus Psuedogymnoascus destructans (Pd) that causes the syndrome has been found in four other states (MN, MS, NE and OK). This deadly disease has and continues to cause massive bat mortality in eastern North America. Since the winter of 2006–2007, bat population declines ranging from 80–97% have been documented at surveyed hibernacula. Although exact numbers are difficult to determine, biologists estimate that losses may approach 5.7 to 6.7 million bats since 2007. This mortality represents the most precipitous decline of North American wildlife caused by infectious disease in recorded history. Regrettably white-nose syndrome was confirmed in Wisconsin on March 28th, 2014. As of May 14, 2015, 14 sites in eight counties have been confirmed with either the disease-causing fungus or white-nose syndrome. Bats at sites in Grant, Crawford, Richland, Door and Dane county have tested positive for white-nose syndrome, while the fungus known to cause the disease has been confirmed at sites in Iowa, Dodge and Lafayette counties. Monitoring bat populations is crucial in states like Wisconsin that are currently considered unaffected, both for early identification of the disease and to develop pre-WNS baselines in this region. The bat populations of Neda Mine have been inspected for WNS annually for the past five hibernation seasons and continue to be inspected at least annually. Unfortunately, on 4/29/15 bat swab samples that were collected for Pd surveillance from spring emergence trapping at Neda Mine were positive for Pd. No visible fungus or evidence of wing damage were observed on the bats sampled. We have installed a thermal infrared surveillance system at Neda Mine. Thermal infrared surveillance is an effective tool because it can detect the change in a bat’s body temperature as it arouses out of torpor, and because WNS-infected bats arouse more frequently than healthy bats. Baseline information on Neda Mine’s bats will allow the infrared surveillance effort to detect WNS almost immediately if/when the disease arrives in the site. We plan to place four self-powered ultrasound detectors at four entrances to Neda mine. The weatherproof detector will record all winter and we will retrieve the unit in late May after bats have emerged in the spring. The detectors turn on every five minutes and record for 90 seconds. When recording, the echolocation calls of any bat flying near the detector will be recorded and saved. The saved calls can help establish timelines of emergence in spring and whether bats are flying in midwinter. Monitoring bat entrance activity will help us better understand spring emergence behavior prior to and post-WNS infection. Investigating temporal and environmental impacts on bat spring emergence can help better understand timing of management for bats across the state.

We also conduct fall and spring trapping of bats with harp traps and mist netting at the Neda Mine entrances. This allows us to gather important data on bats, including baseline weight and WNS wing scoring before and after hibernation as well as collecting tissue for genetic work. When a bat is in the hand of an observer it can be examined for signs of WNS and samples for diagnostics are then easy to acquire. The focal species are Myotis lucifugus, Myotis septentrionalis; Eptesicus fuscus; and Perimyotis subflavus.