Autumn’s annual mid-September Ohio appearance brings with it the departure of leaf cover and migratory birds, along with the disappearance of Big Brown bats. The bats aren’t leaving town, though. Instead, they’re taking up residence in their hibernating areas — which may be the same space where they resided over the summer: your attic!
The shift to a bat’s hibernation behavior begins when cool fall nights reduce insect activity. Remove the food source, and bats are suddenly motivated to begin their migration. In some instances, these migrations may be very short … to the tune of only a few miles from their summer homes.
In the case of Big Brown bats, there’s really no need for a long-distance migration to a warmer climate. Long migratory flights demand large reserves of energy — in this case, the bat’s limited fat reserves. A short migratory flight saves energy, and there’s an ample supply of suitable areas to weather Ohio winters in the area. This particular bat species prefers hibernation locations above ground, in homes, dams and other structures. The bottom line? Big Brown bats are plump, healthy and ready to nap in their own neck of the woods.
Why do Big Brown bats hibernate in attics?
Heat rises. That’s a fact of nature, and one that Big Brown bats take full advantage of where the winter months are concerned. Attics typically offer temperatures ranging between 35 and 40 degrees thanks to warm air rising from heated human living space below. This makes the attic an ideal location for hibernation, since a warmer environment allows bats to reduce their metabolic processes during hibernation while avoiding the risk of freezing.
If your see signs of bat activity in your attic, you should strongly consider a bat exclusion. Once bats begin their hibernation, they will remain inside your attic until spring.