All Illinois bats are protected under the Wildlife Code (520 ILCS 5/1.1).
Bats may not be shot, trapped, transported, or held in confinement except when a bat is found in an area where they may have contact with humans or domestic pets.
Where Do Bats Live in Illinois?
The cave regions of southern Illinois and the valleys of the Mississippi, Illinois River, and Chicago River have ideal natural bat habitats and the highest abundance of bats. Big brown bats, little brown bats, Northern long-eared myotis and tri-colored bats are all colonial bats.
Bat exclusions can be installed when outdoor temperatures exceed 50° F at dusk. Insects are not active at lower temperatures, and all bats in Illinois are insectivores.
When Can You Remove Bats in Attic in Illinois?
Between May 15th to August 5th, you cannot get rid of bats from your attic.
During the spring and summer, females will form maternity colonies in the hollow of trees, attics, or little used buildings. If you find a group of bats in your attic during the spring and summer, tread carefully.
At birth a young bat clings to its mother. When the mother feeds each evening, the young bat is left in the attic. If one were to implement bat removal at this time, the young bats would be stranded inside the attic with no way to feed.
After about three weeks, the young can fly and will start feeding on insects, but they will continue to nurse until they are about 1½ months of age. Once the pups can fly, we can install bat exclusions and a one way valve to get rid of bats in your attic.
Some skill is required to identify all potential entry points because bats can enter through holes as small as 3/8″ (the diameter of a dime) or spaces 3/8″ by 7/8″.
Bat Removal during the Winter in Illinois
During the winter they usually roost in mines and caves. If natural habitats aren’t available, bats will winter inside buildings. If able, leave the bats alone for the winter and install exclusions once it gets warm.
They enter a state of bat hibernation called torpor. To survive long periods without a meal, the animals slow their breathing and heart rate to fall into a deep sleep. Unlike true hibernation, bats in this state can wake briefly on warmer days and leave their roost to find meals.
If bats are evicted during one of these warmer months, they won’t have a safe place to return when the temperatures drop again.