I have been too quick. The idea description already mentioned this point.
To look for sounds which might become a reliable way to protect aircraft from birds is an interesting topic.
But I don't think it works for greater ditances - what it should because of the high speed of an a/c.
I have watched birds which were circled by a peregrine. As long as the peregrine was near to them, they had no panic at all and they didn't abscond.
The reason is: the peregrine is a very slow flyer when it flys horizontally.
Only when the peregrine falls from the sky vertically other birds go into a spiral descent and try to reach trees or other shelter (if they notice it soon enough).
