Bat Nation

10/07/2026

International Bat Week is at the end of October. Of the eight bats found in Wisconsin, four are state-threatened species: big brown bat, little brown bat, northern long-eared bat (also federally endangered) and tricolored bat; and one, the silver-haired bat, is of special concern, meaning the population is declining and in need of conservation action.

It makes sense to recognize these special mammals because for many little brown bats, Wisconsin is their winter hibernation destination! Huge numbers return each fall to just a few underground mines in our state. Mines provide safe refuge until spring when they again fly at night over farms, forests and neighborhoods throughout the Midwest.

The Wisconsin Bat Conservation Network includes Wisconsin Bat Ambassadors and other volunteers who work in cooperation with and under guidance from DNR staff to support bat conservation efforts state-wide, and they’re focused on protection of these important sites. You can learn more at https://www.wbcn.net/

10/05/2026

Some of Wisconsin’s bats are flying south for the winter.

The silver-haired bat (Lasionycteris noctivagans) pictured here roosts mostly in trees, so we don’t usually see them. However, when they’re migrating across more populated areas, they may curl up for the day where they're easier to spot!

If you find a bat that seems out of place, just give them space. They may spend several days and up to a few weeks in the same location.

Volunteers are monitoring these bats, and you can report sightings by taking a photo and emailing it to [email protected] along with the location.

05/10/2026

04/24/2026

Of the eight bat species found in Wisconsin, four are state-threatened. One of these, the little brown bat (Myotis lucifugus), is showing rebounding numbers, thanks in part to the habitats found in state natural areas.

In summer, little brown bats may roost in tree snags, bat houses and buildings across Wisconsin. But come fall, many of them head to a few SNAs, where they can find very specific habitat to use from October through April.

Unlike the other examples on this list, however, the bat habitat at SNAs isn't a holdover of Wisconsin's native landscapes. It's a byproduct of industrialization – abandoned mines, to be specific.

Two large mines in particular, both within state natural areas, provide the vast majority of shelter for little brown bats overwintering in the state. Despite being relics of industry, these sites offer ideal conditions critical to a significant proportion of the nation's little brown bats.

Learn more about Wisconsin's State Natural Areas and the remarkable species they help protect in the latest issue of Wisconsin Natural Resources magazine: https://issuu.com/wisconsinnaturalresources/docs/wisconsin_natural_resources_magazine_spring_2026/s/154416529

Photo Credit: Heather Kaarakka