This is interesting and I have at times heard birds take off, and it seemed like it was the sound of the first one taking off, and how many immediatel after that, then the rest would decide to either take flight or not. I could see the alarm happening, but no vocal cry, and thought that it was an interesting effect that the birds likely homed into listening to that noisy takeoff.

And even if it is not noisy to us humans, their ears and brains may well be 'tuned' towards listening to the wing noises as an elementary flock protection method. Yes, the noisy one may get caught, but it's heightened energy into the wingbeats will surely change the tone and so gives the degree of warning to the rest of the flock.

Of course it it pre-set to a defensive flight bias, check things from the air, and return if safe.

It is nice to know that my own little observations have been scientifically proven to be accurate.