A Mission to Save the Florida Bonneted Bat from Extinction

Stephanie Brinez, VG21, and her colleagues form the Miami Bat Lab, which works to conserve urban bat populations 

In an urban area like Miami, bats don’t have a lot of natural areas to roost, says Stephanie Brinez, VG21, an endangered species interventions specialist for Bat Conservation International (BCI). Luckily for the flying mammals, a couple of key factors are working in their favor.

First, Zoo Miami is located next to a habitat that bats love: the Pine Rocklands, with a lake and an open area that provide foraging spaces. Second, the zoo has partnered with the global nonprofit BCI to form the Miami Bat Lab, under whose mandate Brinez and colleagues are working to save the Florida bonneted bat from extinction. This particular bat has been listed as endangered by the U.S. Fish and Wildlife Service since 2013, and its populations in urban areas have been especially vulnerable to commercial and residential development. 

“We set up specially designed bat houses on poles at the zoo, some next to the lake and others near the Pine Rocklands,” Brinez said, referring to an area of pine trees, some with cavities making them bat-ready, growing over limestone. It’s a uniquely south Florida habitat that bonneted bats prefer but that has been decimated by development and hurricanes and is now considered critically imperiled.

“Many houses had bats move in right away,” Brinez said. The hurricane-resistance structures have separate interior chambers, allowing the bats to move to cooler rooms depending on the angle of the sun—an important feature as climate change leads to extreme temperatures.

Living Under a Microscope

In addition to providing habitat, the houses help the Bat Lab team monitor overall bat health. The researchers set up cone-shaped nets under the houses to catch guano, or bat poop, which the scientists collect weekly and send to a lab for DNA testing. From the results, researchers learn what the bats are eating and how the animals’ diet differs from that of bats in other environments.

“Usually, people are worried about bats spreading diseases, and while bats are known to carry viruses, the risk of infection to humans is very low. The guano is harmless unless it's in giant amounts that would only be found in caves.”

Stephanie Brinez, VG21

Researchers also can observe the bats, thanks to long poles equipped with cameras that they extend up to the bat houses to count the population. Motion-activated cameras capture photos of bat life, including shots of the animals entering and exiting the houses.

Brinez and her colleagues use a third method of examination, as well: acoustic monitors. Because Florida bonneted bats typically fly above the tree canopy, each of the sound detectors—six on zoo property and over a dozen more across Miami Dade County—must be positioned at least 12 feet off the ground, preferably on poles in open areas or on building exteriors, as foliage can muffle or block bat sounds from reaching the microphones.

Bats usually make higher-frequency sounds than what the human ear can pick up, but the Florida bonneted bat has a lower-frequency call,” said Brinez, who first conducted acoustic bat monitoring as an undergrad at Florida Atlantic University before interning for the U.S. Fish and Wildlife Service in California and receiving her master’s in conservation medicine from Cummings School of Veterinary Medicine at Tufts. That lower frequency makes bonneted bats identifiable, but it also means the monitors record a lot of background noise. To pinpoint the bonneted bat call, researchers run the recordings through specialized software then manually vet the audio.

Brinez analyzes data from both the acoustic monitors and the cameras to track types of species present, to update population figures, and to look for increased bat activity. Higher activity indicates that bats are using the resources in a particular area—important in identifying potential land to preserve, she said. Over time, long-term analysis allows researchers to identify changes in behavior patterns, providing clues to how bats are responding to factors such as disease, urban development, climate change, and hurricanes. 

Bat Origin Story

Brinez first saw a bat when she was a child, spending the summer with family in Colombia. When a lone bat flew inside, “everyone was freaking out, and I was afraid they were going to kill it,” she recalled. “But I’m the type of person who won’t even kill a spider in my house. So I went and caught the bat and let it go outside.”

She’s still a bat advocate. Putting a positive spin on the oft-maligned creatures is a big part of Brinez’s job for BCI, and she often speaks with community members who may not welcome winged neighbors.

“Most importantly, we tell people that bats aren’t dangerous,” she said. “Usually, people are worried about bats spreading diseases, and while bats are known to carry viruses, the risk of infection to humans is very low. The guano is harmless unless it's in giant amounts that would only be found in caves.”

What’s more, Brinez said, bats can eat up to two-thirds their weight in insects over the course of a single night. In mosquito-rich Florida, that’s a major selling point. “If you don't like flying insects, then the bat is your animal!”

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