Bats scream and we listen.

06.21.24

By Kristen Pope

Kitti's hog-nosed bat, bumblebee bat
Some bats are tiny, like this bumblebee bat. Yoshi & Keiko Osawa.

Bats are tricky to study. These tiny nocturnal mammals can fly up to 100 miles per hour, and some, like the bumblebee bat (Craseonycteris thonglongyai), weigh just two grams, with inch-long bodies. During the day, most species roost out of sight in caves, rock crevices, tree cavities, or even human-made structures. Since it can be difficult to spot bats visually, scientists often use another method to learn about them: sound. The science of bioacoustics involves studying animals, like bats, through the sounds they make. Since many bats rely on echolocation, bioacoustics is an essential tool for Bat Conservation International (BCI) scientists.

Christen Long acoustic processing
BCI Acoustic Data Specialist Christen Long. Amanda Adams.

BCI uses bioacoustics in a number of different conservation initiatives, from learning about the preferred habitat of Endangered bats to finding ways to help bats survive white-nose syndrome (WNS), a deadly bat disease that continues to decimate hibernating bat populations in North America.

Monitoring Critically Endangered species in Rwanda

In Rwanda, BCI, Rwanda Wildlife Conservation Association (RWCA), and other partners used bioacoustics to learn about the Critically Endangered Hill’s horseshoe bat (Rhinolophus hilli). The species was last recorded in 1981, and many thought it was extinct until a 2019 expedition, during which BCI and partners successfully captured two individuals in Nyungwe National Park.

Hills Horseshoe Bat Survey - Rwanda 2019
Hill’s horseshoe bat. Jon Flanders.

After capturing the two bats, Dr. Jon Flanders, BCI’s Director of Endangered Species Interventions, and BCI colleagues and partners recorded the bats’ echolocation signature for the first time. Researchers worked with park rangers to deploy acoustic monitors around the park to learn more about the distribution of the species. Over 500 nights, 1.2 million sound files were collected at 120 different locations. At 39 of these sites, the acoustic recorders collected calls from the Hill’s horseshoe bat. These recorders are a valuable tool showing where the bats are present or absent, which allows scientists to learn more about the species’ core range, and select focus areas for future research. RWCA Conservationist Peace Iribagiza is now working to train rangers in other Rwandan national parks to expand the monitoring efforts.

Boosting Florida bonneted bat conservation efforts

In South Florida, BCI and Zoo Miami are using bioacoustics to learn more about another Endangered bat: the Florida bonneted bat (Eumops floridanus). Endemic to South Florida, this is one of the rarest bat species in the U.S., and it is threatened by habitat loss through development and severe storms caused by climate change. Acoustic monitoring is helping Dr. Melquisedec Gamba-Rios, BCI’s Regional Director for Latin American & Caribbean Initiatives, colleagues, and partners, identify high-priority areas the bat uses for foraging. This information is helping them plan where to install artificial roosts for the species.

Florida bonneted bat
Florida bonneted bat. MGambaRios.
FBB Acoustic recording
Acoustic monitor at Florida bonneted bat box. MGambaRios.

To learn more about the areas that bats use, BCI and partners installed acoustic monitors to record the evening activity of bats. They found Zoo Miami to be a hotbed of activity, recording 13,000 bat calls per night, with other areas, such as golf courses and parks, recording 7,000 – 9,000 calls per night. After analyzing the data, the researchers determined that 9% of these calls were made by Florida bonneted bats. More than half were made by Mexican free-tailed bats (54% Tadarida brasiliensis), and northern yellow bats (Lasiurus intermedius) made up 17% of the recordings.

Echolocation “feeding buzzes” share important clues in the fight against white-nose syndrome

Echolocation data can provide insight beyond where bats are found. It can also share information about what the bats are doing in a given area. BCI’s Science Team, including Dr. Amanda Adams, BCI’s Director of Research Coordination, is studying a way to support bats, like little brown bats (Myotis lucifugus), by fattening them up before they enter hibernation in order to give them the best shot at surviving the winter. To do this, scientists are installing artificial prey patches that lure insects into areas with UV lights, which will, in turn, allow insectivorous bats to effortlessly feast.

Researcher working at artificial prey patch. Jason Headley.

The researchers used bioacoustic monitoring to examine the echolocation calls they recorded and categorize them by call type, including the “feeding buzzes” that bats make when they swoop in to eat an insect. They found WNS-affected species fed at the artificial prey patches three to eight times more than bats usually would. This valuable insight will help inform future conservation efforts to improve foraging habitats near important bat sites.

Learn more: Watch a webinar about bioacoustics and bats from Wildlife Acoustics featuring BCI staff members: https://vimeo.com/940925465.

Meet The Scientists

jflanders

Jon Flanders, Ph.D.

Director, Endangered Species Interventions

Jon Flanders, Ph.D. – Director, Endangered Species Interventions

Dr. Jon Flanders is responsible for leading conservation initiatives that effectively address BCI’s global conservation priorities. With over 20 years of experience working on conservation projects across the globe, Jon recognizes the importance of partnerships in delivering social, environmental and economic benefits. Working with a range of organizations, from small non-profits to government departments he can strategically prioritize projects that balance conservation needs with sustainability.

Jon received his Ph.D. from the University of Bristol where he integrated investigations of the ecology, diet, and population genetics of the greater horseshoe bat to advance its conservation. Prior to joining BCI, Jon had worked extensively across Asia and Central America leading a variety of conservation-related research projects, as well as teaching workshops and outreach efforts for local researchers and students. 

Jon is an Adjunct Professor in Ecology and Evolutionary Biology at Tulane University and a Research Associate at the American Museum of Natural History. 

mgambarios

Melquisedec Gamba-Rios, Ph.D.

Regional Director, Latin America & Caribbean

Melquisedec Gamba-Rios, Ph.D. – Regional Director, Latin America & Caribbean

Melquisedec is the ESI Team’s Regional Director for Latin America and & Caribbean Initiatives. In this role, Melqui is responsible for identifying priority areas for the Endangered Species Interventions team to focus, and work with in-country partners to co-develop effective strategies to protect and recover endangered bat species, populations, or habitats. 

Melqui has been working with bat ecology and conservation for over 20 years. Originally from Colombia, Melqui conducted most of his research work in Costa Rica. He received his Ph.D. from the University of Tennessee-Knoxville, where he investigated antipredator behaviors in bats and the implication in bat communication and sociality. He has published work on topics including species distribution, habitat selection, and roost requirements for multiple bat species, with a particular emphasis on the neotropics.

aadams

Amanda Adams, Ph.D.

Director of Research Coordination

Amanda Adams, Ph.D. – Director of Research Coordination

Amanda joined BCI in 2019 and has worked with bats for 20 years. As the Director of Research Coordination, she maintains communication and collaboration among internal and external partners for conservation research across BCI. She runs BCI’s Student Research Scholarship Program and is passionate about developing capacity for bat conservation. Amanda specializes in bioacoustics and has broad research experience, particularly in behavioral and sensory ecology, and is adjunct faculty in the Department of Biology at Texas A&M University. She received her Ph.D. from Western University in Canada and a B.Sc. and M.Sc. from the University of California, San Diego. She completed postdoctoral research at Ben-Gurion University of the Negev and Texas A&M University.

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