Southern Wisconsin Seeing More Fireflies
Drought conditions have improved their habitat, entomology professor explains.
Fireflies at the Forest Exploration Center in Wauwatosa on July 3, 2025. (Wauwatosa originates from the word ‘firefly’ in the language of the Potawatomi tribe). Anna Marie Yanny/WPR
Kimberly Mackowski of West Allis recently took a walk at dusk through Wauwatosa’s Forest Exploration Center.
“The whole forest was blinking,” Mackowski said. “It’s like someone put blinking lights on, right at the forest entrance.”
Like many people around the state, the local blogger has noticed an uptick in fireflies this summer. Mackowski runs a site highlighting parks and preserves in southeastern Wisconsin. She’s lived in the Milwaukee area for about 30 years, and said she’s also noticed more fireflies in her backyard.
“Some years are better than others, but definitely this year has been more of a peak,” she said.
Entomology professor Dan Young said this year marks a short-term win for the regional firefly population. The area is coming out of a drought, leaving abundant ground moisture for fireflies to thrive in during their larval and pupa stages.
“Compared to the last couple years, people would probably be noticing a lot more. I’m certainly noticing more in my own backyard.” said Young, who teaches at the University of Wisconsin-Madison and serves as the director of the Wisconsin Insect Research Collection. “But looking at it more long-term, I would say … this is a pleasant blip in the radar.”
Researchers like him are still concerned about firefly numbers over time.
“When I think back 10 years, 15 years, (there were) way more than now,” Young said.
Scientists say the insects’ biggest threats are habitat loss, pesticide use and light pollution.
“When there’s a lot more evening light, it can mess up their communication,” Young said. “That can interfere with the ability of them to, you know, have their little evening romances and find one another.”
Wisconsinites can help by turning off porch lights and floodlights, he said. They can also limit using pesticides and herbicides in their gardens.
The majority of a firefly’s life happens in their larval stage, underground. After about two years, they pupate and emerge. Female fireflies like to lay their eggs in moist soil.
Unfortunately, the wet conditions fireflies thrive in also are good for mosquitoes.
“When you’ve got big firefly populations, you’re probably going to have a bad mosquito year,” Young said.
Mackowski practices “gardening for wildlife” in her own backyard.
“If you want fireflies in your yard … the very first place to start would be: don’t use pesticides,” she said. “If you’re spraying for the mosquitoes, you’re killing everything else.”
There are about 2,000 species of fireflies worldwide. Scientists say there’s a need to track firefly populations over time to assess their risk.
Milwaukee’s Schlitz Audubon Nature Center is hosting a firefly monitoring hike on July 23. Attendees will walk through prairie, looking for flash patterns of the common eastern firefly, said Melanie Ziolecki, the center’s environmental educator and children’s events lead.
“How we monitor them is counting the amount of flashes we see in a certain period of time,” Ziolecki said.
The team will help collect data for the Firefly Atlas, an effort to track firefly species in North America.
“It’s important because of the habitat loss of these species,” Ziolecki said. “We can kind of create a trend, and maybe follow that trend, and help these fireflies in their future.”
Have you seen more fireflies this year? was originally published by Wisconsin Public Radio.
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