I don't know if this adds to the topic but last month I was in a spot with plenty of California Quail.
Out of curiosity I used my iPhone to get to the Cornell Labs birds site and called up an assortment of recorded quail calls, each identified as to it's purpose.
Surprisingly to me, the speaker on the iPhone was loud enough to have the sound carry a bit and I can say, without a doubt, the birds reacted appropriately to the calls I played, whether it was an alarm call or an assembly call.
Lots of fun playing the assembly call and then seeing them slowly gather near me over the course of the next few minutes.
