I recently downloaded a couple of torrents from isohunt and/or demonoid.com that might interest you.....
Common Bird Song
Seeing Through Native Eyes by Jon Young (this one is included under the torrent titled "The Induction Series")
Advanced Bird Language by Jon Young
Journey To the Ancestral Self by Tamarack Song
The Lakota Way by Unknown
If you have or can get a library card that should open up an entire world of audio, especially bird song.
If you are unfamiliar with torrents email me at mullikencc at yahoo dot com
I would be glad to help you out and there aren't many such valuable tools for self education as torrents, one of the most powerful tools the internet has to offer.