The sighting of a bat has been known to make people run for cover, screaming and shielding themselves—fearful of the bite from above.
But bats that suck blood for a living—such as the vampire bat—don’t call Minnesota home. In fact, the bats that hang around Minnesota often devour the most wide-spread blood sucker of all—the mosquito.
And to dispel even more fear of the tiny bats around Minnesota, and to investigate what may help the hurting populations, local students have been working with the Minnesota DNR and Camp Ripley staff to better understand the state of Minnesota’s bats.
Since 2013, researchers from the DNR Nongame Wildlife Program and Central Lakes College have conducted a survey as part of the three-year project to study summer breeding habits of the state’s forest bats. And thanks to those studies, they found this summer that Minnesota now has eight bat species.
The discovery of the evening bat was the most notable discovery so far.
“It’s very exciting to discover a new bat species in the state,” said DNR endangered species coordinator Rich Baker. “The evening bat’s northern most historic range is limited to central Iowa. As our project proceeds, we’ll be keeping an eye out for more evening bats. For now, we don’t know if this was an isolated individual blown north in a storm, or if this species has indeed expanded its range into Minnesota.”
They can say the bat was calling Minnesota home because it was a lactating mother—her young ones were likely within a few hundred yards of where she was found.
Wisconsin wildlife staff were also pleasantly surprised when they found scores of evening bats this summer, the first time in 60 years that one has been recorded there.
The Minnesota bat was caught in early July at the Minnesota Army National Guard’s Training Site in Arden Hills.
That discovery was an added bonus to the work of finding more information about the northern long-eared bat. The group knew the northern long-eared bat was in trouble due to white-nose syndrome killing off up to 99 percent of some colonies. The syndrome is caused by a fungus growing in the caves where four of Minnesota’s bat species hibernate. The troubling white-nose syndrome started in New York in 2006 and has continued to spread.
“There were rumblings that the white-nose syndrome was decimating the population,” according to Dr. Bill Faber, CLC natural resources department head. “That’s when we got on board.”
They’ve been at it ever since and the study has one year remaining.
In April 2015, the USFWS listed the northern long-eared bat as threatened. Then in January, they added that the critical habitat determination was not prudent.
“While critical habitat has a fundamental role to play in recovering many of our nation’s most imperiled species, in the case of the northern long-eared bat, whose habitat is not a limiting factor in its survival, designating it could do more harm than good,” said Tom Melius, the U.S. Fish and Wildlife Service’s Midwest Regional Director.
They reasoned that bringing out the critical habitat designation would make public the most critical areas and possibly make those sites susceptible to too much human exposure. That’s increasingly a problem that is being dealt with in some areas by limiting human access or creating decontamination areas that visitors must use. While white-nose syndrome generally spreads bat-to-bat, recent finding of white-nose syndrome in Washington points to humans as the cause of spread, as the bats exposed to the fungus in Minnesota or Wisconsin caves will not fly that far out of their range, but people that explore caves do.
Since its discovery, white-nose syndrome or the causative fungus has spread to 32 states and five Canadian provinces, killing more than 5.7 million cave- or mine-hibernating bats.
How the study works
The study staff and volunteers head out to areas including Chippewa National Forest, Arden Hills, Camp Ripley and Camp Norris near Cloquet. In these places, the groups set out huge volleyball-like nets called mist nets in areas where bats are swiftly searching for insects.
The bats are live trapped in the nets, a good night includes catching 20 to 30 bats. They are all checked over, weighed, measured, identified and a wing band is attached. Radio transmitters are attached to female northern long-eared bats.
The nets need to be checked every 10-15 minutes to avoid overstressing the bat and to avoid getting too many bats in a net at once, which can take some real wrangling, Faber explained, even if they are only as big as your thumb. The students do everything a researcher would need to do in studying the animals, including catching, recording data, decontaminating all equipment—everyday—tracking bats and working together to find out the overall health of the area bats. As Brian Dirks, DNR animal survey coordinator at Camp Ripley explained, without the students, all the work of the study could not be done. The bat study is supported by the Environmental and Natural Resources Trust Fund, the National Guard, and donations to the Nongame Wildlife Fund.
“It’s an invaluable resource for the students,” Faber said.
Faber started part time at CLC in 2004 and is now the program head as well as internship coordinator. He says about 20 students are now involved in these type of internships, with five helping with the bat studies last summer.
One of the major discoveries of the state bat studies seems to be the importance of dead standing trees and live trees with cavities, according to Faber and Dirks.
“They like standing dead trees, Faber said.
The bats roost in them and raise their young there, and they don’t just pick one and call it home, Dirks said. Apparently they will fly from tree to tree when they feel they need to move on. That’s important because the findings can show foresters and lot owners that leaving some dead trees or live trees with cavities standing is important to the livelihood of the bat, as they may use many trees in their lifetime.
After the bats have a tracking device glued to them, the students and staff involved will follow the bats using telemetry. They only have six to 10 days to track the bat since the tracking device falls off that soon. So far, they have found that it’s not so important how large the tree is, but a dead tree with a hollowed out area is all a family of bats needs to rest and welcome more family members.
Another important discovery Faber and Dirks agree on is that the bats have a larger home range than was originally thought. It was common before to think that bats traveled 300-400 yards from the roost tree, but their research shows that the range can be 1 to 2 miles.
Dirks said their focus continues to look at the lives of the bats during the summer months, while other groups are studying what is happening during the hibernation and how to combat the fungus showing up in the state’s caves.
Those studying the bats know the importance of the bat to our environment and hope to show that to those around them. Yet some people still dislike the bat. And people like Faber hear about it.
“Most people, unfortunately, hate them,” Faber said. “They are eating our enemies yet they are severely persecuted.”
According to the U.S. Fish and Wildlife Service, bats are important to the nation’s ecology and economy, eating tons of insects nightly and providing a natural benefit to farmers and foresters. Some research estimates that bats provide at least $3 billion annually in economic value.
So while the bat seems to frighten most people, it would seem the world would be a much more frightening place without the world’s only flying mammal.
Bats breeding now
According to the USFWS, in the bat world, breeding is still taking place when males begin swarming near hibernacula, the hibernation area. After copulation, females store sperm during hibernation until spring, when they emerge from their hibernacula, ovulate, and the stored sperm fertilizes an egg. This strategy is called delayed fertilization. After fertilization, pregnant females migrate to summer areas where they roost in small colonies and give birth to a single pup. Maternity colonies, with young, generally have 30 to 60 bats, although larger maternity colonies have been observed. Most females within a maternity colony give birth around the same time, which may occur from late May or early June to late July, depending where the colony is located within the species’ range. Young bats start flying by 18 to 21 days after birth. Adult northern long-eared bats can live up to 19 years.
Brian Dirks, DNR animal survey coordinator at Camp Ripley said those looking to offer a place for bats to set up a roost can put up a bat box. This could be especially helpful if you have few dead trees in your area.