I keep hearing about how fireflies are dying off.  The numbers are way less than they used to be.  
I’ll agree that they’re maybe a bit lower than they were in thd 70s and 80s, but when they first start showing up,  there seem to be a lot. 
At least in my yard.
However… we went to a very nature-ish town on Lake Michigan this summer. Tons of trees and vegetation.  You’ll see deer pretty much every night.  I expected to see a TON of fireflies.
I saw maybe 5.
How is it my very populated, habitat-reduced suburb of Chicago has so many fireflies and a woodsy area of Michigan barely has any?
How are the firefly numbers in your area?
John Vogel