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Little brown bats are dying; why we should care

Once among the most common bat species in the United States, the little brown bat has been reduced to just 1 percent of its former population. Jennifer Longsdorf, who heads the bat conservation program for the state Division of Fisheries and Wildlife, is coordinating research and educating the public on the plight of the bats, which have died by the thousands in recent years from white-nose syndrome, a fungal disease that thrives in the moist caves where bats hibernate. Metro Minute recently spoke with Londsdorf on why the bats matter and how the public can get involved in saving them. (This interview has been edited and condensed.)

Why should people care about little brown bats?


They play a huge role in our ecosystem and are very helpful in our environment. They help reduce a number of pesky insects in our backyard, which includes disease-carrying insects. Basically, they act as organic pest control.

How endangered are they?

White-nose syndrome is the number one threat to bats in Mass. It has caused mortality rates of over 99 percent, and up to 100 percent in other states. Some scientists predict that the widespread species will be reduced to just 1 percent of its pre-white-nose syndrome population by 2030.

How would the environment of Mass. be affected by the loss of so many bats?

The insect population would increase, which would result in a higher pesticide and or insecticide use. If you use more pesticides, then more chemicals will go into the environment, which could also result in human health impacts. Agricultural communities would experience more crop damage from insects and would, in turn, have to spend more money on pesticides to protect their crops.

Is there any hope of saving them?

We certainly have hope. Last summer, in 2017, our contractors were able to find three new maternity colonies, so they’re still out there. Because of their incredibly low reproductive rate, it’ll be a very slow recovery. Female bats of most species only have a single pup a year.


What’s been your biggest challenge?

Being able to find and capture the females. We’re interested in radio tagging adult females so we can track them back to their summer maternity colonies. Once we find them, it’s not difficult to capture them.

How can people identify colonies on their property?

Usually just by seeing them or the piles of guano that are left under their roost site. We recommend people estimate how many bats [there are] by standing outside around sunset and counting them. People who have bats in their attic can determine the size of the colony based on the amount of guano. Little brown bats tend to roost in barns and sheds in colonies of 30 or more, while big brown bats [which are not endangered] have roost sites in attics and in people’s houses in colonies of 10.

How can Mass. citizens help?

We encourage people to provide an alternative site and a safe home for them to go to when they’re driven from the house. I created a guide to bat houses that has all the info you need to know. Be a citizen scientist and spread the word about reporting bat colonies to MassWildlife, help dispel myths and fears about bats. Reduce pesticide use to ensure there are plenty of insects for bats to feed on. If you must exclude or evict bats from your home, ensure the process is safe and humane by following MassWildlife’s guidelines.


Longsdorf will be with MassWildlife’s table at the Franklin Park Zoo on Tuesday, April 17th, sharing more information about bats in honor of National Bat Appreciation Day. To report the location of a little brown bat colony of ten or more, e-mail jennifer.longsdorf@state.ma.us.

Margeaux Sippell can be reached at margeaux.sippell@globe.com. Follow her on Twitter @MargeauxSippell.