Lincoln Park Zoo is trying to learn more about bats in the Chicago area and is asking the public for help.
There are eight known bat species in Illinois, but there is no precise tally for Chicago.
So far, the Wildlife Institute has found evidence of four species near the zoo.
Residents can email bat photos and tips to batsignal(at)lpzoo.org.
Conservationists at the zoo's Urban Wildlife Institute are listening in on bat calls with special detectors attached to trees, poles and fences that pick up the animals' sonic patterns.
Getting a better picture will help scientists monitor the population and possibly gain insight into a disease called white nose syndrome that has decimated bat populations in the eastern U.S.
The fungal disease has not yet been detected in Illinois.