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    • Wisconsin Bat Facts to Share This Halloween
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    Wisconsin Bat Facts to Share This Halloween

    Pabio Posted on

    With Halloween upon us, spooky symbols of the holiday abound, including bats.

    It turns out that this is also the case International Bat Weekwhich celebrates the role of bats in nature. Coincidence? Maybe not.

    The connection between bats and Halloween dates back to Samhain, an ancient Celtic festival where large bonfires were lit to ward off evil spirits. Bats dove near the fire, interpreted to be the spirits themselves. And then, of course, there are vampire bats, which drink blood (but rarely that of humans). Over time, these winged creatures of the night have become synonymous with the spooky season.

    Over the past decade, the hundreds of thousands of bats that live in Wisconsin have faced a frightening situation: the rise of white-nose syndrome, a fungal disease that has devastating effects on the bat population. state mouse.

    More: How spiders, bats and black cats became the animal ambassadors of Halloween

    Today, there are small signs that those numbers could rebound. Here’s what you need to know about Wisconsin bats and how you can help them thrive.

    What types of bats live in Wisconsin?

    There are eight species of bats in Wisconsin, divided into two groups: cave bats and tree bats. They all eat insects.

    Tree bats, which in Wisconsin include silver-haired, eastern red, hoary and nocturnal bats, migrate south for the winter, usually leaving in September and October. Wisconsin’s cave dwellers – the big and little brown bats, which are the most common in the state, as well as the tri-colored and northern long-eared bats – spend their winters hibernating in caves or mines.

    All of these species face threats to their survival.

    Where can you find bats in Wisconsin?

    During the summer months, bats are found throughout the state. During winter, tree bats disappear and cave dwellers seek out places to hibernate, which differ depending on their species.

    The vast majority of the state’s little brown bats, for example, congregate in three hibernation sites, said Jennifer Redell, a conservation biologist and cave and mining specialist for the Wisconsin Department of Natural Resources . One is Néda Minea former iron mine in Dodge County, and the other two are former frac sand mines in Pierce County. The Neda Mine is one of the largest bat hibernation sites in the Midwest.

    There are up to 200 other hibernation sites, such as other mines, natural caves and railway tunnels, where small numbers of other cave-dwelling bats spend their winter.

    Big brown bats are more tolerant of cold and drought, Redell said, so they sometimes don’t hibernate until December — and when they do, they’re more likely to hibernate in people’s homes.

    What is white-nose syndrome and how has it affected Wisconsin bats?

    White-nose syndrome is a fungal disease that kills bats across North America. Named for the white, powdery fungal growth on the wings and snouts of infected bats, it was first discovered in Wisconsin in 2014 and has had a catastrophic impact on the bat population there. ‘State.

    More: Disease has ‘catastrophic’ impact on Wisconsin bats

    Little brown bats, in particular, suffered the most, Redell said. Since the disease took hold in Wisconsin, the DNR detects 90 percent fewer echolocation calls from little brown bats when they are active during the summer months.

    At the two Pierce County hibernation sites, she estimated that the bat population dropped 80 percent after the onset of white-nose syndrome, from about 150,000 to about 30,000. (He Counting bats in the Neda Mine is difficult due to the mine’s deep cracks and crevices.) The number of bats in some of the smaller hibernation sites has dropped to zero.

    More: Could ultralight violet light save Wisconsin bats from a deadly fungus?

    But the figures seem more reassuring in recent years. Over the past three winters, Pierce County sites have housed about 60,000 bats, Redell said, and during the summer, volunteers count higher numbers of bats leaving their summer roosts, especially along the Mississippi and Wisconsin rivers.

    What is the reason for the improvement?

    “Bats have been around for more than 50 million years,” Redell said. “They are very adaptable…we hope their adaptability will help them in the era of white-nose syndrome.”

    There could be fewer fungi in the environment over the years, she suggested, or frac sand – a drying agent – ​​reduces the fungal load in mines when bats are not there .

    What other threats do bats face?

    Since the fungus that causes white-nose syndrome does better in warmer conditions, warming temperatures at hibernation sites due to climate change could have negative effects, Redell said.

    Bats are also experiencing habitat loss — not so much the loss of forests and caves, she explained, but being pushed out of houses, barns and other buildings. Wind turbines can also harm bats due to collisions.

    And yet bats have a marketing problem: Some people think they’re scary and don’t want them around. This can lead to direct killings, Redell said.

    Why are bats important to humans and the environment?

    Perhaps the greatest benefit of bats to humans is their diet. A single bat can eat thousands of insects per nightridding the air of mosquitoes and other parasites.

    In 2018, a study from UW-Madison who analyzed bat droppings found that Wisconsin’s little brown bats ate 17 different types of mosquitoes, including nine carrying West Nile virus. The same study found DNA from 24 different agricultural pests in droppings, supporting the estimate that bats are saving Wisconsin farmers. hundreds of millions of dollars per year in pesticides.

    Although not found in Wisconsin, nectar-eating bats also help pollinate crops. They are the only pollinators of agave, a major ingredient in tequila..

    How can you help Wisconsin’s bats?

    Start by building a bat house, which provides a safe summer refuge for bats, Redell suggested. Grow plants native to Wisconsin, which in turn attract native insects that bats feed on.

    If you need to “exclude” bats from a building, do it in winter, when they are not using their summer roosts. Avoid doing this during their maternity period, she said, which runs from June 1 to August 15.

    More: What you can do in your garden to help Wisconsin’s endangered species

    More generally, Redell said, people should take steps to protect access to caves and mines and stay away during the bat hibernation period, which in Wisconsin begins Oct. 1 and ends on May 15.

    “The best and greatest thing anyone can do is stand up for bats…especially if someone says something derogatory or spreads misinformation,” she said .

    Where can people see them safely?

    During the summer months, a few state parks are home to significant bat colonies, Redell said, including Peninsula State Park in Door County, Devil’s Lake State Park in Baraboo and Yellowstone Lake State Park in Blanchardville.

    Sometimes parks have special programs, Redell said, but it’s not necessary to see them: Stay about 30 minutes after sunset, and each night the bats come out of their “bat condos.” mouse,” she said.

    To respect them, stay 15 to 20 feet back, do not use flash and speak quietly or not at all.

    Madeline Heim is a Report for America corps reporter who writes about environmental issues in the Mississippi River watershed and throughout Wisconsin. Contact her at 920-996-7266 or [email protected].

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