I recently downloaded PaulXStretch, a free (pay what you can) vst/standalone for making drones.
Here I’ve recorded a crack of dawn mating frenzy (I assume, I didn’t actually see it, but it sounds like that’s what it might be). I put two short(ish) loops into PaulXStretch, one of the turkeys and one of some other bird chirping.
So it’s two drones, to which I then added the original recordings.
Zip has the original recordings and the separate drones.