This is getting ridiculous.
I think everybody agrees that Duncan is clearly the better defender.
Bird played in a significantly higher-paced and higher scoring era, so comparing raw numbers doesn't make much sense.
Let's look at advanced stats for the playoffs (because I guess we all agree that should be the measuring stick for comparing all time greats, who cares about regular season games against teams with losing records?).
I don't see how anybody in their right mind could say that Bird was a better playoff performer than Duncan.
Actually, Duncan was better, and it's not even close.
And to those who claim that Duncan had it easy in a weak era: I'd take every bet that the Western Conference during Duncan's era was every bit as tough as the Eastern Conference of the Bird Era.