Fifteen months ago, the United Nations declared 2011 and 2012 as the International Year of the Bat to promote awareness about the under-appreciated insect gobbler, pollinator and seed disperser. The bat, you see, has fallen on hard times. There’s no easy way to explain this, so we hope you’re sitting down. Or upside down. Here it goes: Statistics show more than half of bat species in the United States are either suffering steep population declines or they are already listed as endangered. A major reason why is white-nose syndrome — a mysterious disease that is wiping out bats by the millions.