As part of her Circuit Garden project, artist Kelly Heaton makes birds out of electronic circuitry that can be adjusted to produce a wide variety of birdsong. Here she demonstrated with a printed circuit bluejay:
As Heaton explains, the sounds made by the birds aren't recordings...they're generated by the electronics, like a synthesizer.
My "printed circuit birds" are self-contained sound generators. The electronics are [100%] analog: no audio recordings or software are involved. By "analog" I mean that the sound is dynamically produced by the bird's body (circuit), like a vintage synthesizer. In this video, I adjust knobs to change resistance in the circuit, thereby altering the song quality. You can think of this like adjusting neurons in a bird's brain to alter the impulse by which it vocalizes.
(via clive thompson)