https://ccrma.stanford.edu/~tamara/publications/asa_02.pdf
http://www.csis.ul.ie/dafx01/proceedings/papers/kahrs.pdf
you can hear audio samples of the former, here:
https://www.cs.sfu.ca/~tamaras/
The zebra-finch to me kind of like air wheezing out of a balloon... which I think is still indicative of good progress, in a way, in that it does sound like a real-world acoustic process.
