Bat Blitzes Show Many Species in Park

This article was originally published in The Midden – Great Basin National Park: Vol. 20, No. 1, Summer 2020.

BioBlitz participants getting a close look at a bat held by Nevada Department of Wildlife biologist Jason Williams.

NPS Photo by Gretchen Baker

by Kelsey Ekholm, Joseph Danielson, and Bryan Hamilton, Bat Biologists

Humans remain largely unaware of the vast numbers of bats flying above us each night. Bats are the only mammals capable of true flight and use high frequency echolocation calls to detect and capture insect prey. Although most echolocation calls are above the range of human hearing, insects are able to detect, avoid, and interfere with bat calls in the night skies.

Bats provide billions of dollars in ecosystem services through insect predation which reduces food costs, the need for harmful pesticides, and disease risk from insect vectors such as mosquitoes. Unfortunately, bat populations face unprecedented threats such as habitat loss, climate change, wind energy development, and disease. White-nose syndrome (WNS), a fungal disease, has spread across the US in last decade, killing millions of bats in its wake.

In an effort to learn more about populations, the park led two survey events for bats last summer. The first of these events was the Great Basin National Park (GRBA) BioBlitz, held August 20-22. GRBA’s BioBlitz is an annual citizen-science event which focuses on a different group of organisms each year and serves to increase our knowledge of the target taxa within the park, as well as educate the public. The Mojave Network (MOJN) Bat Blitz was held at GRBA August 26-30. The MOJN Bat Blitz is an annual event in which biologists from parks within the Mojave Network get together for a coordinated survey effort of the bat community in a specific area (the host park or unit).

Setting up a net for one of the Bat Blitzes.

NPS Photo by Joseph Danielson

The goal of these events was to increase our knowledge of the bat communities in and around GRBA and how they utilize the landscape, as well as to educate the public (in the case of the GRBA BioBlitz). With threats to bat populations increasing in the United States, these survey efforts are crucial to develop management strategies.

For both blitzes, groups went to various survey areas (e.g., water sources, flyways, near roosts) to capture bats via mist nets or harp trap. For each individual captured, groups recorded the species, sex, age, reproductive condition, weight, and other relevant measurements. All captured bats were released by hand and no specimens were collected. Acoustic surveys were conducted in conjunction with trapping events at most sites.

The GRBA BioBlitz had over 60 participants and conducted surveys at six locations over two nights. Through this effort, 821 bats representing 8 species were captured and 7 species were detected acoustically for a total of 9 species documented overall, including Pallid bat (Antrozous pallidusi), Townsend’s big-eared bat (Corynorhinus townsendii), big brown bat (Eptesicus fuscus), hoary bat (Lasiurus cinereus), silver-haired bat (Lasionycteris noctivigans), western small-footed bat (Myotis ciliolabrum),long-eared myotis (M. evotis), long-legged myotis (M. volans), and Mexican free-tailed bat (Tadarida brasiliensis).

Volunteers watch how to process a bat during the 2019 BioBlitz.

NPS Photo by Joseph Danielson

The MOJN Bat Blitz had 39 participants from nine NPS units (Great Basin, Death Valley, Joshua Tree, Lava Beds, Lake Mead, Mojave Network, Pinnacles, Timpanogos Cave, and Zion), as well as other organizations including Nevada Department of Wildlife, U.S. Fish and Wildlife Service, Great Basin Institute, Christopher Newport University, Oregon State University, and volunteers. During this blitz, 17 sites were sampled over 4 nights which resulted in the capture of 701 bats of 9 species and the acoustic detection of 10 species, for a total of 10 species documented overall, including canyon bat (Parastrellus Hesperus) in addition to the 9 species documented during the GRBA BioBlitz.

Two of the many bats caught during the Bat Blitzes.

NPS Photo by Joseph Danielson

With the help of the volunteers who participated in these events, we were able to survey areas of the park we would not normally be able to, as well as survey multiple areas in the park simultaneously. This gave us new insight into the bat activity and landscape use throughout the park and at varying elevations and habitats. Furthermore, through pairing our bat trapping efforts with acoustic surveys, we were able to compare these data to better understand the acoustic variation within our park’s bat species and give context to previous recordings from these areas. These data, funded by the National Park Service and Southern Nevada Public Land Management Act, are being used to minimize the impacts of wind energy, recreational caving, and disease on bat populations. On the next warm summer evening, look up and consider the unseen aerial ballet between bats and insects, and how it helps humans.