I don’t know specifically

I don’t know specifically about nature sounds, but I use the Edirol and it does a pretty good job of picking up ambient sounds. I use it in weddings to record background sound just in case my camcorder loses audio for some reason. The best thing about it is you can pick if you want to record WMA or MP3, and you can pick the bitrate. It will record for a really long time depending on the size of your card.