For my free portions, I tried variations on humming and blowing into the mic. I don't have any melodic instruments with me (percussionist), so it was difficult to get something that sounded improvised. I tried to do that with my snare practice pad in free2, but it still sounds fairly rhythmic. However, I noticed both kind of sounded like wildlife (I was thinking monkeys), so they fit well with the score recordings
For my rhythmic portions, I tried to redo a portion of a song I've enjoyed recently - Beat Connection off of the LCD Soundsystem s/t/ - by putting some of the drum part onto an 808 in Ableton. I then passed this loop through free1 and saxophoner.
For my scored poriton, I found two nice sections of the nature recording, one where it the noise of the birds greatly crescendos, and one where the recorder is breathing into the microphone (easy to hear at the end)