Glacier National Park Bat Inventory and Monitoring Project, Summary Report 2011-2022

Bate, Lisa; Potter, Megan

In response to the discovery of White Nose Syndrome (WNS)--the deadliest emerging wildlife disease threatening North American bats—we initiated Glacier National Park’s (GNP) Bat Inventory and Monitoring Program in 2011. Prior to this, no formal bat surveys had ever been conducted in GNP. We have now confirmed the presence of 10 bat species in GNP: Little Brown Bat, Long-eared Bat, Long-legged Bat, California Myotis, Yuma Myotis, Big Brown Bat, Eastern Red Bat, Silver-haired Bat, Hoary Bat, and the Western Small-footed Bat. Our findings have contributed to range expansions for the California Myotis, Yuma Myotis, Eastern Red Bat, and Western Small-footed Bat. From 2011 to 2022, we conducted 87 mist-netting sessions where we trapped and processed bats at 65 different sites within GNP. We processed 1,149 individuals comprised of nine different species. Although we have yet to capture an Eastern Red Bat in GNP, we have identified them through acoustic surveys. Waterton Lakes National Park, just north of GNP, caught 13 of them in one summer. We conducted night-time acoustic inventory and monitoring surveys at 101 different short- and long-term detector locations across 34 grid cells within GNP from 2011 to 2022. Our two long-term and year-round bat detectors located in the Belly River and along Lake McDonald sampled for 732- and 665-nights total. Along with acoustic and capture surveys, we also inspected structures throughout the park for bat use. Since 2016, we conducted 187 formal emergence counts at 36 different structures within GNP. We counted a total of 18,760 bats emerging across all surveys and on average we counted about 100 bats per survey. Through building surveys and our bat roost database, we confirmed roosts in at least 258 of the 761 total structures in GNP. In 2020, we began swabbing individuals for Pseudogymnoascus destructans (Pd), the causative agent of WNS. All bat swab samples returned negative for Pd. We detected bat activity during winter months at both the Belly River Ranger Station and the Lake McDonald Campground long-term sites. This supports other evidence that bats do hibernate in GNP, although we have yet to find a hibernaculum. We suspect the eastern edge of GNP to be a corridor for migratory bats, making it even more critical that we have accurate, timely, and reliable baseline data on GNP bat populations to prepare for the highly anticipated arrival of WNS to GNP.