[dh5]

In a previous life I performed research on the neurological basis of birdsong, which is fairly well understood for passerines.

Sounds produced by birds can be divided into two types: songs and calls. Songs are primarily by males to attract mates, and are sung the same song over and over with minimal variation. Females, in turn, are attracted to the males with highest song stereotypy that sound closest to the "ideal" for the species. Calls are used to communicate to other birds of a certain idea, e.g. a predator nearby, and are also consequently standardized.

So while this is indeed very cool, it's my suspicion it won't be recognized as "authentic" by the birds themselves. You can't just "make up" new syllables or sounds and have it be understood.