Pigeon feather sound

A reseach about the different sounds that pigeons' feather make as they take off indicate if they are in danger. I think pigeons may learned to recognize the different sounds based on experience. Evolution may have allowed the birds that can produce different sounds have an advantage, because more of them can escape from danger. However, I don't think their is deliberate I also believe there are people who knew about this as a matter of survival skill. So, I think some of these reseaches are waste of money.

-- Wen from phone