(IL) Chicago Tribune – Crouched in fields of prairie grass under moonlit skies, Matt Hokanson leads workshops three times in the spring to teach new monitors how to count the population of frogs by the number of calls they hear.

There are 13 native species of frogs in Illinois, Hokanson said, but four to five are limited to specific habitats such as sandy areas. The rest can be found in wetlands where habitats are located by aerial photographs taken by the U.S. Fish & Wildlife Service and the Audubon Society Chicago Region. More