Old wives tale. They did a test once where they targeted flocks of birds with a 60's era missile tracking radar... the type that would make you sterile just looking at it. There was no effect on the birds.
thats a myth. At the altitudes where we are most likely to hit birds we are doing like 300-500 ft/sec. Even if it had any affect on the bird at all they still won't have time to get out of the way. AND which way would the bird go? away? How would they turn away? They cant see or hear the airplane coming. Or know which way the airplane is coming from. jeez I put a lot of thought into a myth. I guess I just wish it really worked.