The deluge of dead red-winged blackbirds, grackles, and starlings that fell out of the skies over Beebe, Ark., on New Year's Eve in all likelihood has a simple scientific explanation.

Yet genuine concern spread quickly through the town of about 5,000 on New Year's Eve, and understandably so, as environmental cleanup workers in white jumpsuits descended on Beebe on New Year's Day to pick up thousands of dead birds from roads and walkways.

The main worry was that the birds, like the proverbial canary in the coal mine, were an indicator of a toxic threat – a possibility that has largely been ruled out. Yet the event spooked residents near and far as, in the absence of a final explanation, imaginations are running wild. People have tried to link the bird die-off – which is certainly unusual, though not unprecedented – to everything from a sign of biblical end times to chemical conspiracies, shifts in the Earth's magnetic core, and even proof of UFOs.

IN PICTURES: The red-winged blackbird and other ornamental birds

Movies like "The Core," TV shows like "FlashForward," and books like the "The Doomsday Key," which all involve scenes featuring birds falling out of the air, fuel superstitions that birds such as ravens and vultures have prophetic properties or serve as omens. It's a long-standing belief among mankind.

Roman augurs, for one, were known to watch the flights and behavior of eagles for clues to how upcoming battles would turn out. In some cultures, birds are seen as souls occupying the liminal space between heaven and earth. In others, they are considered harbingers – often of doom.

"To Taoists, for example, birds indicate the violent uncontrollable primordial willfulness of the 'barbarians,' " William Doty, a religion professor at the University of Alabama and the editor of Mythosphere magazine, told the Monitor back in 2005.

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In Beebe, City Councilor Becky Short told The New York Times that residents were jokingly theorizing about biblical end times or a UFO collision to explain the unsettling deluge of birds.

Others took it more seriously. "[T]his strange occurrence can't help but lead this Christian writer to remember the beginning of that 1988 movie 'The Seventh Sign,' wherein signs of the apocalypse – as outlined in the Book of Revelation – seem to be coming true," writes the Examiner.com's Paula Mooney.

The Old Testament does make references to an angry God dispatching birds, but the Bible does not mention dead birds specifically.

Other conspiracy theories – such as fallout from secret government weapons testing – also stretched the bounds of credulity, although a nearly simultaneous fish kill on the Arkansas River did raise official concerns about a toxic release, potentially from nearby industry. Early tests, however, show no signs that any animals were poisoned.

So what did happen?

Several dozen birds have been sent out for autopsies at two different labs. Early theories are that the flock was flushed out of a roost, potentially by fireworks, and died after being caught in a sudden storm or, possibly, from stress related to New Year's Eve noise. The fish kill in the Arkansas River, authorities say, was probably caused by a localized disease affecting one species of fish.

If the Beebe bird rain portends anything, says Arkansas state ornithologist Karen Rowe, it would be the broad but gradual decline of native bird populations around the US. "That's more worrying than this individual event involving a species that's very common," she says.

IN PICTURES: The red-winged blackbird and other ornamental birds