Find a bat hangout? The state of Michigan wants to know about it
Michigan is home to nine bat species, five of which are designated as threatened or endangered.
OTTAWA COUNTY — State wildlife officials are calling on Ottawa County residents to track local bat populations this summer as part of an expanding research initiative to map critical summer habitats.
The Michigan Department of Natural Resources and the Michigan Natural Features Inventory launched the second year of the Michigan Bat Roost Monitoring Program this month, relying on volunteers to identify where bats gather to shelter and raise their young.
Local data plays a vital role in tracking the mammals. According to the Ottawa County Department of Public Health, the region typically sees an uptick in bat activity between May and September.
According to Ottawa County Public Health Department Communications Manager Alison Clark, already this year, 22 bats have been submitted for testing.
“Sixty bats were submitted for testing in 2025. It’s important to note that not all bats can be caught and tested. In those cases, OCDPH may still recommend that individuals exposed to the bat be evaluated by a healthcare provider for rabies post exposure prophylaxis, depending on their exposure,” Clark said.
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While state researchers say that Kent and Newaygo counties yielded the highest density of reports during the program’s inaugural launch last year — ranging from seven to 13 reports each — wildlife biologists seek a clearer picture of Ottawa County's roosts.
The tracking effort arrives amid prolonged ecological strain.
Michigan is home to nine bat species, five of which are designated as threatened or endangered. Populations across the state plummeted following the arrival of white-nose syndrome, an invasive fungal disease that disrupts winter hibernation and has killed millions of bats across North America since 2006.
"Summer bat roosts are critical places where bats rest, raise pups and shelter during the season," John DePue, a DNR bat specialist, said in a statement. "However, these are some of the least understood parts of the bat’s life cycle. By learning more about where bats are roosting, we can better support conservation and management efforts for these species."
While bats hibernate inside caves and abandoned mines during winter, their summer habits rely heavily on man-made structures and mature forests. Pregnant females form maternity colonies in warm, dark locations, including residential attics, barns, bridges and artificial bat boxes.
Public health officials track local bat data closely for other reasons.
In July 2025, the Ottawa County Department of Public Health confirmed the county's first rabies-positive bat of that year, urging residents to report indoor bat encounters while taking precautions to secure homes without harming the animals.
State biologists emphasized that residents who discover a bat colony in a home or barn should report the location but avoid trying to remove or exclude the animals during the summer months. Because young bats, known as pups, cannot fly during the mid-summer maternity season, sealing an entry point can trap flightless bats inside.
Property owners are advised to wait until late August or September, when bats begin migrating toward winter locations, to install one-way exclusion devices that allow bats to leave but prevent their return.
According to state information, there are about 60 animal rabies cases reported each year in Michigan. Of those cases, about 90 percent are in bats.
Bats serve as an essential economic asset to West Michigan agriculture, acting as natural pest control by consuming thousands of night-flying insects hourly, including mosquitoes and crop-destroying beetles, experts say.
Residents can report roosts to the state here.
The online reporting system requires basic operational metrics: the date and time of the sighting, the type of structure, an estimated count of the colony and optional photos. Observations from earlier this spring or from previous years are also accepted.
— Heather VanDyke covers northern Ottawa County for the Ottawa News Network. Contact her at hvandyke@ottawanewsnetwork.org.
