Really? Then how the can they navigate over thousands of miles and find their way home
I can't lay an egg either - proves nothing. Humans are quite capable of navigating long distance and have done so for millenia.
Unless you can show me that birds have some sort of directional sensing facility (like an eye, but for radar) that will tell them from where the threat direction is coming, so they can indeed avoid the aircraft, I think it is highly improbable that radar has any effect whatsoever. What I'm trying to say is, it's bollocks. Turn on your radar on the ground - see what the birds do? Oh yeah, nothing.