I just discovered a really interesting site called “Music of Nature.” Unfortunately, the site has not yet been completed. Evidently, when completed, the site will offer recordings of the calls of many different species of birds, etc. The only area where the site is complete is the insect sounds.
I ran across the site while searching for information about the cicada since it appears that a brood of them are now in our area. Some of these insects have a call that is piercing to hear. Check out some of the sounds here. Listen to the 17-year cicada especially!