Humane Bat Eviction & Exclusion in Michigan

Michigan is home to nine native bat species, including the big brown bat, little brown bat, Indiana bat (which is federally endangered), northern long-eared bat, evening bat, hoary bat, red bat, silver-haired bat, and tri-colored bat (formerly eastern pipistrelle).

Yes, several are. The Indiana bat is a federally endangered species found in Michigan. Additionally, the northern long-eared bat is federally threatened, and several other species, including the tri-colored bat and evening bat, are listed as state-level special concern species due to population declines, largely caused by White-nose Syndrome.

Michigan bats typically begin to hibernate around October or November as temperatures drop and insects (their main food source) disappear, emerging in April or May. They hibernate in specific locations called hibernacula, which offer cool, stable temperatures and high humidity – often caves, mines, or, for some species like the big brown bat, even buildings (attics, wall voids).

The timeline depends on the season, the weather, and the size of the colony. The physical installation of the one-way exclusion devices and the initial sealing of the house usually takes a day or two. However, the devices must be left in place for a specific period—typically several days to a couple of weeks—to ensure every single bat has flown out. Once the home is clear, the technician returns to remove the devices and seal the final holes.

If a single bat is found in the main living area, often opening windows and doors to let it fly out naturally works best, ensuring no direct contact. For consistent bat issues (multiple bats in the house, evidence in attic), it's crucial not to use pesticides or traps. Instead, look for bat exclusion services – identifying entry points and installing one-way exit devices after young pups can fly (typically late summer/early fall). Never handle a bat with bare hands due to the risk of rabies (though incidence is low).