News Study on little brown bats continues

MassWildlife is working to ensure this once-abundant bat species does not disappear forever.
  • Division of Fisheries and Wildlife
  • MassWildlife's Natural Heritage & Endangered Species Program
Little brown bats in an attic.

Last year, MassWildlife asked you to report bat colonies to help better assess where bats are during the summer months in Massachusetts. Your help is needed again this year. If there is a colony of 10 or more bats on your property, please report colonies here. Colonies may be found in trees, buildings, attics, barns, sheds, or other outbuildings. This information will be used to help conserve the state’s endangered population of little brown bats. 

Since the onset of white-nose syndrome (WNS) in Massachusetts, the state’s population of little brown bats has dwindled to less than 1% of what it once was. In one abandoned mine, almost every bat hibernating over the 2008/2009 winter died from WNS—nearly 10,000 bats dropped to just 14. First seen in bats hibernating in a cave near Albany, New York in 2006, WNS is caused by a fungus that grows on cave-hibernating bats during the winter. The growing fungus rouses the bats from hibernation, causing them to use up precious fat stores before fully waking in the spring, leading to starvation. As a result of the drastic mortality from WNS, all species of cave bats that hibernate in Massachusetts are now listed as endangered on the Massachusetts Endangered Species List.

Two species of bats—the little brown bat and the big brown bat—form summer colonies in trees, buildings, attics, barns, sheds, and other outbuildings in Massachusetts. Little brown bats also hibernate in caves during the winter, where they can contract WNS. Before WNS, little brown bats were the most common bat species in the state. Now, they are one of the species most affected by WNS in Massachusetts. We are especially interested in understanding the post-WNS status of little brown bat populations, including knowing the size and location of their colonies.

Similar to 2017, we hope to partner with a contractor to survey little brown bat populations throughout Massachusetts, continuing the work initiated last summer by the Biodiversity Research Institute (BRI).

During the 2017 summer bat maternity season (June–July), MassWildlife partnered with BRI to survey bats throughout Massachusetts and to locate little brown bat maternity colonies where mothers group together to raise their young. Bats were located by listening for their calls with special acoustic detectors, mist netting, radio telemetry, and visits to reported roost sites. Little brown bats were found at 9 of the approximately 30 sites surveyed. Little brown bats were detected acoustically at 6 locations, while 7 individuals were captured in mist nets. Three new maternity colonies were also located.   

MassWildlife is committed to reducing the vulnerability of the surviving populations of little brown bats. This summer, MassWildlife will continue to capture and radio track these rare bats to maternity colonies at locations where the species was previously detected or reported. Additional roost sites that are located will also be monitored. Monitoring long-term population changes  greatly increases what is known about little brown bat populations in Massachusetts and will assist in their recovery.

“This is a great opportunity for the residents of Massachusetts to help in the conservation of an endangered species right in their backyard,” says Longsdorf, who is a part of MassWildlife’s Natural Heritage and Endangered Species Program. Many thanks to those who previously reported bat colonies and roost sites throughout Massachusetts. Last year, over 100 reports were received from the public. Over one-third of the landowners who reported colonies last year were contacted for additional information and about one-fourth of the sites were visited by Biodiversity Research Institute.

Learn more about white-nose syndrome in Massachusetts.

Division of Fisheries and Wildlife 

MassWildlife is responsible for the conservation of freshwater fish and wildlife in the Commonwealth, including endangered plants and animals. MassWildlife restores, protects, and manages land for wildlife to thrive and for people to enjoy.

MassWildlife's Natural Heritage & Endangered Species Program 

The Natural Heritage & Endangered Species Program is responsible for the conservation and protection of hundreds of species that are not hunted, fished, trapped, or commercially harvested in the state, as well as the protection of the natural communities that make up their habitats.


Did you find what you were looking for on this webpage? * required
We use your feedback to help us improve this site but we are not able to respond directly. Please do not include personal or contact information. If you need a response, please locate the contact information elsewhere on this page or in the footer.
We use your feedback to help us improve this site but we are not able to respond directly. Please do not include personal or contact information. If you need a response, please locate the contact information elsewhere on this page or in the footer.

If you need to report child abuse, any other kind of abuse, or need urgent assistance, please click here.