The mystery of what killed tens of thousands of fish Ark. remains unsolved

The mystery of what killed tens of thousands of fish that washed up along the Arkansas River late last year can't be solved, state wildlife officials announced Wednesday, but they do have a theory about what caused birds to fall out of the sky in a small Arkansas town on New Year's Eve.

The Arkansas Game and Fish Commission issued separate news releases on the Dec. 29 fish kill and the New Year's Eve event in which red-winged blackbirds began raining down, evoking images of the apocalypse. The agency issued the releases after autopsies and multiple tests were conducted on the fish and birds.

Scientists determined it's likely that unusually loud noises reported before the birds began falling frightened them so much that they flew off in the dark, even though they have poor night vision and typically do not fly at night. The Fish and Game Commission also said New Year's Eve fireworks likely led the birds to fly at a lower-than-normal altitude and into buildings or trees. It's estimated that 4,000 to 5,000 birds fell before midnight.

Less is known about the fish kill. None of the tests conducted on fish or water samples from the area turned up anything conclusive, the agency.