The Little Brown Bat Struggles to Survive

White-nose Syndrome (WNS) continues to advance across the country, killing at least a million bats each year. It was first detected in New York in February 2006 and reached the Straits Area during the winter of 2013-14. By the winter of 2014-15 it was found throughout the Upper Peninsula. As of this year, WNS has killed bats in 29 states and 5 Canadian Provinces.

WNS is a disease caused by an invasive, cold-loving fungus that thrives in caves and mines where bats hibernate during the winter months. This white fungus grows on the nose, ears, wings and tails of hibernating bats. The bats are irritated by the fungus, so they frequently wake from hibernation and use up their winter fat reserves long before spring arrives. These starving bats often leave their caves in midwinter, only to starve or freeze to death. At some sites nearly all of the bats have died. It is estimated that the bat population in the northeastern U.S. has declined by 80% because of WNS.

Here at the Straits we have witnessed a dramatic decrease in the population of the Little Brown Bat (Myotis lucifugus), which probably hibernate in some of the infected caves located in the eastern Upper Peninsula.

In years past, Little Brown Bats were a common evening sight on Mackinac Island. At Historic Mill Creek Discovery Park we would often see them flying just above the water of the mill pond catching insects. Recently, however, bat sightings have become quite rare around here.

If the Little Brown Bat does disappear from our forests we will certainly miss these valuable insectivores, because of the large number of mosquitoes and midges that they eat every night.  They often consume half of their body weight per night, which translates to hundreds of flying insects per hour.

Although healthy bats can live to be over 10 years old, the female can only have one pup per year, so the population will not recover anytime soon. Hopefully some of the local bats have survived the winter and we’ll see a few again this summer. The forest just wouldn’t be the same without them.