By Mary Morris
If you have been out and about at Springbrook Nature Center or other Fridley City Parks, you may have noticed some new additions – brown boxes on the tops of metal poles. You may have asked yourself, “What is that for?? A bird nest? Bee homes? Some kind of GPS receiver?” If you guessed bat box, you guessed correctly! These brown boxes have been installed to provide summer roosting spots for our resident bat species.
Minnesota has seven native bat species, depending on variations in their ranges. They can be grouped into two categories – migrators and hibernators. As small, warm-blooded mammals who rely on insects and flowers for food, bats need a strategy to survive Minnesota’s frigid winters. Bats in the migrator group, like silver-haired bats, eastern red bats and hoary bats, journey south to warmer regions where food sources remain available year-round.
The hibernator group includes the little brown myotis, big brown bat, northern long-eared bat, and Minnesota’s smallest bat, the tri-colored bat. Once nighttime temps dip below 50 degrees Fahrenheit, these bats all hibernate together in caves and mines. In the summer, both migrators and hibernators roost in trees, buildings, caves or mines. Bats, which can live to be as old as 30 years, are loyal to their roosting spots and will return to the same place year after year.
While bats aren’t everybody’s favorite night flyer, they are important to our ecosystems. Minnesota bats are mostly insectivorous. Many use echolocation to find and catch their prey. They emit high-frequency sounds which bounce off of near-by objects. Their large ears catch the echoes, creating a spatial map of the objects. Many catch their prey in the skin membrane connected to their tail, then transfer the insect to their mouth mid-flight. In addition to controlling annoying biting insects, bats also help the agricultural industry by eating lots of crop pests, thus decreasing the need for pesticide use.
Though bats still have an important role to play, they face some tough challenges in our current environment. Here in North America, bats are severely threatened by white-nose syndrome. White-nose syndrome is caused by a fungus which thrives in the cool, damp caves where many species hibernate. It can be spread from bat to bat or by cave-visiting humans. The disease was first discovered in New York in 2006, and has now spread as far east as Minnesota. Additionally, bats are severely impacted by habitat loss – particularly through removal of forests that provide roosting spots and good foraging territory.
So, how can we help out our Minnesota bats? In addition to spreading the word about these cool critters, we can help provide them with safe habitat and roosting spaces. The bat boxes installed in the Fridley Parks were an Eagle Scout project completed by Joey Hatton. You can check them out at Springbrook Nature Center, Moore Lake Park, Sand Dunes Park and the Innsbruck Nature Area. Hopefully, over the next few months our resident bats will discover and enjoy these new homes.
Marry Morris is an interpretive naturalist at Springbrook Nature Center, 100 85th Ave. NW in Fridley. Director Mike Maher welcomes comments at Mike.Maher@fridleymn.gov or 763-572-3589. Go to springbrooknaturecenter.org for more information.