White Nose Syndrome, a disease caused by a fungus that has killed millions of bats across the eastern U.S., now threatens to decimate colonies in Minnesota. There is no cure, but there is also not much known about bats. Therefore scientists across the state are trying to help bats survive by understanding the summer habitat they use to reproduce.

Here Ron Moen, Associate Professor at the Department of Biology, University of Minnesota, Duluth, listens to the signal he receives from transmitters attached to female bats to locate their roosting places within Itasca State Park. May 2016. On assignment for MPR News

Several nets are set up across less traveled trails in the state park. Bats prefer them as flight corridors in densely grown forests. The nets are very fine, so that bats cannot echo-locate them.

A little brown bat (myotis lucifugus) is protesting its temporary captivity with high- pitched squeaks. Each bat is checked for its sex, weight, general health, and, if a female, for pregnancy.

Itasca State Park, home to several bat colonies.

Northern long-eared bat caught in the net.

When a bat is caught it will be removed carefully from the net, as is being done here by Taryn Upmann-Grunwald, and put into a small cotton bag to be carried to a nearby tent that serves as a field laboratory.

While each bat is ringed, pregnant bats may also be equipped with tiny transmitters to later locate their roosting places. Each transmitter must weigh less than 10 percent of the bat’s body weight of about 12 g.

Peter Kienzler from the U of M, Duluth, has a close look at another protesting bat. After all documentation is done, the bat will be released into the night immediately.