What is the state of greater prairie chickens in Illinois?

There is a certain period in the spring when the last frost advisories are announced, Tax Day has passed us by, planting season begins in earnest, and the greater prairie-chicken males begin to reluctantly diminish in their spring courtship displays.
In Illinois, data has shown that female greater prairie-chickens visit the booming grounds in the highest numbers close to the tenth of April, the peak of breeding in our state.