Cornell University in New York has a Library of Natural Sounds.  Most
sounds available are from birds, but they do have a listing of non-bird
sounds.  The person to speak with is Andrea Priori at (607) 254-2407.
Make sure that you order the sounds way in advance. I got a letter from
her the other day that stated the next available recording time
was mid June.  I even asked, or should I say begged, her if I could pay
extra and get the sounds back earlier.  No chance!

You might also try Rykodisc recordings on tape and CD.  They have an
"Atmosphere Collection."  I have been in contact with them to utilize a
portion of one of their rainforest sounds CD in an upcoming exhibit.  So
far so good, but I have not been given the official okay.

I hope this helps!

Monica Buntin
Education Coordinator
The Dallas Arboretum
Dallas, Texas