The Birds April 11, 2006 Dear Investor: The market often catches a cold, as they say, but what if it catches the avian flu? The bird flu has become, like terrorism, the world economy’s persistent bogeyman. When dealing with an amorphous but potential cataclysm like a global pandemic, it’s important for investors to evaluate the risks and decide if tactical changes are warranted. We’ll start with the investing axiom that changes are rarely...