My mom is a master naturalist and has listened to (hours of) frog field recordings to determine which types of frogs are at specific locations for our departmen

My mom is a master naturalist and has listened to (hours of) frog field recordings to determine which types of frogs are at specific locations for our department of natural resources (IIRC). There is a paper that describes how to calculate minimum adult population from audial surveys. If you still need to scratch that itch, I'm sure there are still some interesting applications along these lines.