From "The Chicago Wilderness Calling Frog Survey"

Western Chorus Frog part 1

Western Chorus Frog part 2

http://www.chicagowilderness.org/what-you-can-do/volunteer/

Introduction to The Chicago Wilderness Calling Frog Survey

Critters heard are a chorus (many individuals) of grey tree frog and cricket frog, and an individual green frog "glubbing" occasionally. The call of the tree frog is sometimes described as a "trill" and the cricket frog has a bit of rattle or clacking in its song.

Feeling Human