Bit more reading via Google, and another comment from me:
Just come across a page by Henry Niman where he forecast bird flu from Qinghai in July “will soon arrive in areas to the east, south, and west, of the summer location.”
Yet when it spread to the north instead, he wasn’t fazed – just said bar-headed geese move north from Qinghai to a lake in Russia.
And never mind, apparently, this happens at a time they’re flightless. (Presumably, Niman figures they walk pretty fast.)