Michigan residents are being asked to help researchers identify where bats spend their summers as part of a statewide conservation effort now entering its second year.
The Michigan Bat Roost Monitoring Program, a partnership between the Michigan Natural Features Inventory and the Michigan Department of Natural Resources, is collecting reports of bat roosts from community members across the state. Researchers use the information to better understand where bats rest, raise their young and shelter during the summer months.
During the program's first year in 2025, residents submitted more than 130 bat roost observations from 52 Michigan counties. Most reports came from private property, providing researchers with information they otherwise would not have access to.
"We didn't really know where they were spending their summers," said Nicolette Sexton, a research assistant with the Michigan Natural Features Inventory. "Their summer habitat is really important. It's where they spend the summer, have their babies and raise their young."
Michigan is home to nine bat species, five of which are listed as threatened or endangered at the state or federal level. Bat populations have declined significantly because of white-nose syndrome, a fungal disease that affects hibernating bats.
The fungus causes bats to wake repeatedly during hibernation, depleting the fat reserves they need to survive winter. White-nose syndrome was first detected in Michigan in 2014 and has since been found in all known bat winter roost sites in the state, Sexton said.
Despite their reputation, bats provide significant environmental and economic benefits. They consume large numbers of insects, including mosquitoes and agricultural pests. Sexton said big brown bats, one of Michigan's most common species, are particularly effective at controlling beetle populations that can damage crops.
According to the DNR, bats help support Michigan agriculture by reducing the need for pesticides and naturally controlling insect populations.
Researchers are asking residents to report bat roosts found in homes, barns, bat boxes, bridges, trees and other structures. Reports can be submitted year-round through an online survey and may include photos and information about the number of bats observed.
Participants who have previously reported a roost are also encouraged to provide updates and conduct emergence counts by watching a roost site at sunset and counting the bats as they leave. Researchers say the information can help track population changes over time.
"Summer bat roosts are critical places where bats rest, raise pups and shelter during the season," DNR bat specialist John DePue said in a statement. "By learning more about where bats are roosting, we can better support conservation and management efforts for these species."
To participate in tracking bats, please go here.