Giant List of Mysteries you've probably never heard of (3/3)

December 31st, 2010 – 5000 black birds started slamming into building, breaking
windows and dying instantly in the air. According to officials in Arkansas where this happened, they blamed the fireworks that must have startled the birds.

December 31st, 2011 (the following year) Despite the fireworks ban, 200 birds
were reported dead. There were no significant reports of bird deaths any other time including the 4th of July.