Documenting bat species at Cherokee Marsh

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In August, Wisconsin master naturalist and DNR bat ambassador Kathlean Wolf led two evening walks to learn about Wisconsin’s most lovable and amazing mammals: bats! The walks were so interesting and popular that a third bat walk has been added on September 5, 2025. (see https://www.cherokeemarsh.org/event-details-registration/bat-walk )

The walks took place in the Cherokee Park neighborhood park on Burning Wood Way, through the trees and grassy paths along the shore of the Yahara River (Cherokee "lake").

Kathlean presented information about our state’s eight species of bats, how humans benefit from their presence, the impact of white-nose fungus and other threats to their survival, and how we can help our Wisconsin bat species survive and thrive. Bats are major consumers of agricultural and forest pests and predators of biting insects, including mosquitoes. Bats also play an important role in reducing risks of insect-borne diseases such as the West Nile Virus.

After Kathlean's introduction, participants plugged into their tablet computers three Echometer Touch sensors borrowed from the Wisconsin DNR to eavesdrop on bat calls and identify which species fly the skies over Cherokee Marsh.

DNR bat specialist Jennifer Redell cautions that species identifications with acoustic sensors are never perfect, since bat call structures can be similar. All analysis softwares use a statistical approach to assign a most-likely species to a bat call. In some cases, the program may identify a bat species that may not actually be present so, to further validate the presence of species, in most cases additional surveys are recommended.

However, over the two evenings of the August bat walks, the Echometer sensors gave plenty of indications of the presence of bats, even if we can't absolutely rely on the exact IDs. The sensors suggested the possible presence of six of Wisconsin's eight species: Little Brown, Big Brown, Hoary, Silver-haired, Tricolored, and Eastern Red. On one evening, we had almost 40 "hits" for Big Brown Bats, and over the two evenings, we had 3–5 "hits" for Little Brown Bats. This is exciting data, because the Little Brown, Big Brown, and Tricolored bats are all listed as threatened species in Wisconsin.

The Wisconsin DNR staff is developing an acoustic survey protocol for small properties (like Cherokee, Warner, Token Creek, State Parks, etc.) and groups that wish to develop their own repeatable surveys and routes, tracking their results over time. The plan is to have the protocol ready for Friends groups, Bat Ambassadors, and other volunteers by the spring 2025 survey season.

In the meantime, you can help bats by planting native plants, shrubs, and trees that support a wide variety of insect life, and don't use insecticides in your yard—especially not commercial spraying for mosquitoes. Let the bats eat the insects!