Northern Illinois actually has annual cicadas, so we get the noise every year to some degree. I'm inclined to believe these are 17 year critters that have fallen out of sync over the centuries so you get a continuous stream now.
The major brood here, XIII, has a sub-brood that shows up 4 years ahead of time. 2020 was very noisy.
The major brood here, XIII, has a sub-brood that shows up 4 years ahead of time. 2020 was very noisy.