Theories abound over exactly why birds have been falling from the sky and fish are dying in alarming numbers in the U.S. They range from the ridiculous (government conspiracy) to the plausible (power lines) to the Biblical (Armageddon is approaching).
The latest incident was the discovery on Monday of 500 dead birds along a highway in Louisiana. Experts there say those birds likely hit power lines.
That followed the deaths of some 3,000 blackbirds in the small town of Beebe, Arkansas. Scientists blamed New Years fireworks for confusing the birds, which then crashed into homes, cars and each other.
So far the two incidents appear to be separate.
"I haven't found anything to link the two at this point," 'Louisiana's state wildlife veterinarian Jim LaCour said.
Fish are also dying. Thousands of dead and dying fish found washed along a 20-mile stretch of the Arkansas River. And hundreds of miles north in Maryland, tens of thousands of small fish have died in Chesapeake Bay. No one knows why.
Back to the bird theories, Dan Cristol, a biology professor and co-founder of the Institute for Integrative Bird Behavior Studies, is not a fan of the fireworks idea. He said that is unlikely, unless "somebody blew something into the roost, literally blowing the birds into the sky."
He is in favor of the power line theory, although he said the birds may have been ill or startled from their roost before hitting them. "They don't hit a power line for no reason."
They are sticking to the fireworks theory in Arkansas, however. Experts there say they may have caused frightened birds to fly lower than normal, where they crashed into homes and other objects.
"The blackbirds were flying at rooftop level instead of treetop level," Karen Rowe, an ornithologist with the Arkansas Game and Fish Commission said. "Blackbirds have poor eyesight and they started colliding with things."
Other theories include thunderstorms, poison, secret government experiments, parasites and the second coming of Jesus.
Mass bird deaths are not uncommon. Around 90 are currently listed on the U.S. Geological Service's Web site, with five incidents where at least 1,000 birds were killed.