This is based on projects published on the Adafruit industries website, notably the ABC Soundboards with NeoTrellis project (https://learn.adafruit.com/abc-soundboards-with-neotrellis). I adapted it to play should clips of nature-based sounds from the National Park Service and published in the public domain.
The sounds include 15 common birds and a "dawn chorus", 4 insect sounds such as crickets, mosquitos and bees, 4 frogs sounds included a chorus of spring peepers, 3 mammals including a wolf and 4 additional camping and weather sounds.
Grab the sound files at: http://bit.ly/2FssIGh
Download the code at https://github.com/KaleidoscopeSci/NeoTrellis