haha that's so funny.
I suspect the man was talking about the amount of pigeons that one pigeon could be responsible for in it's lifetime, ie the amount of offspring produced by the offspring produced by the pigeon if you see what I mean. Cus that could amount to a lot thinking of what a pigeon's family tree might look like. I read the same sort of statistics here in the UK about stray cats. Still, 600,000 seems a little bit of an over-estimation.
Can't wait to find out if the radio station reads your email. Good on you for sharing your opinion I say! x