Nature Lab

Species of Conservation Concern

Monitoring Cave Bats

Every winter MDC Bat Ecologist Jordan Meyer and other trained staff enter caves across Missouri to count hibernating bats. While some bat species migrate, species that hibernate provide a perfect opportunity for biologists to monitor their population numbers.

During the counts, the bats’ welfare is a top priority. “We want to keep disturbance to a minimum, so we don’t make the bats use up their energy reserves any faster than they need to,” explains Meyer. “Bats come in and out of hibernation naturally, but every extra rousing burns more fat that they’re counting on to make it through the winter.”

Researchers visit each cave only once every other year and try to complete counts in less than three hours. Equipment and clothing are disinfected before and after entering a cave to prevent the spread of white-nose syndrome (WNS), a deadly disease caused by a fungus that grows on the exposed skin of bats.

“If bat numbers are small, we can do a hand count,” says Meyer. “But when bats are tightly clustered, we photograph the bats with a high megapixel camera and then come back to the office to blow up the image and do the counting on a computer. This not only increases accuracy but reduces disturbance to the bats because we can get in and out more quickly.”

MDC began routinely monitoring bats in 1975. These efforts have increased in recent decades as bat populations have declined from the spread of WNS, habitat loss, and climate change. Data is shared with the U.S. Fish and Wildlife Service and used for regional management decisions.

Want to help bats? MDC Resource Science Supervisor Tony Elliott says, “The easiest thing you can do is to avoid disturbing them in caves.”

Monitoring Cave Bats at a Glance

MDC and partners monitor more than 500 hibernacula (caves and other subterranean places where bats hibernate) across the state.

Caves provide bats with safety as well as stable temperatures that allow bats to use minimal energy to maintain body heat while hibernating.

Main species that hibernate in Missouri’s caves:

• Indiana bat (Federally endangered, Missouri endangered)
• Gray bat (Federally endangered, Missouri endangered)
• Northern long-eared bat (Federally threatened, Missouri endangered)
• Tri-colored bat (Missouri species of conservation concern)
• Little brown bat (Missouri species of conservation concern)
• Big brown bat

Partners

U.S. Fish and Wildlife Service, Cave Research Foundation, Missouri Department of Natural Resources (DNR), DNR’s Missouri State Parks, Mark Twain National Forest, and others.