New Year's revelers in a small Arkansas town were enjoying midnight fireworks when they noticed something other than sparks falling from the sky: thousands of dead blackbirds.

A dead red-winged blackbird

The red-winged blackbirds rained out of the darkness onto rooftops and sidewalks and into fields. One struck a woman walking her dog. Another hit a police cruiser.

Birds were "littering the streets, the yards, the driveways, everywhere," said Robby King, a county wildlife officer in Beebe, a community of 5,000 northeast of Little Rock. "It was hard to drive down the street in some places without running over them."

In all, more than 3,000 birds tumbled to the ground. Scientists said Monday that fireworks appeared to have frightened the birds into such a frenzy that they crashed into homes, cars and each other. Some may have flown straight into the ground.

"The blackbirds were flying at rooftop level instead of treetop level" to avoid explosions above, said Karen Rowe, an ornithologist with the Arkansas Game and Fish Commission. "Blackbirds have poor eyesight, and they started colliding with things."

But Rowe stopped short of declaring the mystery solved, saying labs planned to test bird carcasses for toxins or disease. Another theory was that violent thunderstorms might have disoriented the flock or even just one bird that could have led the group in a fatal plunge to the ground.

A few stunned birds survived their fall and stumbled around like drunken revelers. There was little light across the countryside at the time, save for the glimmer of fireworks and some lightning on the horizon. In the tumult, many birds probably lost their bearings.

"I turn and look across my yard, and there's all these lumps," said Shane Roberts, who thought hail was falling until he saw a dazed blackbird beneath his truck. His 16-year-old daughter, Alex, spent Saturday morning picking them up. "Their legs are really squishy," she said.

For some people, the scene unfolding shortly before midnight evoked images of the apocalypse and cut short New Year's celebrations. Many families phoned police instead of popping champagne.

"I think the switchboard lit up pretty good," said Beebe police Capt. Eddie Cullum. "For all the doomsdayers, that was definitely the end of the world."

Paul Duke filled three five-gallon (19-liter) buckets with dead birds on New Year's Day. "They were on the roof of the house, in the yard, on the sidewalks, in the street," said Duke, a supervisor at a nearby school. A few dead birds still littered town streets Monday.

The birds will not be missed. Large roosts like the one at Beebe can have thousands of birds that leave ankle- to knee-deep piles of droppings in places. On Monday, a few live birds chirped and hopped from tree to tree behind the Roberts' home.

"The whole sky turns black every morning and every night," Roberts said.

At Duke's home, bird feeders stood empty. He fills them when bluebirds come in the summer but leaves them empty during blackbird season.

"They'd eat 50 pounds (22.5 kilograms) of feed a day," he said. "You couldn't keep them full."

Red-winged blackbirds are among North America's most abundant birds, with somewhere between 100 million and 200 million nationwide, according to the Cornell Lab of Ornithology in Ithaca, New York. Rowe put the number of dead in Beebe at "easily 3,000." Thousands can roost in one tree.

The Game and Fish Commission shipped carcasses to the Arkansas Livestock and Poultry Commission and the National Wildlife Health Center in Madison, Wisconsin. Researchers at the University of Georgia's wildlife disease study group also asked for a set of birds. Test results could be back in a week.

A few grackles and a couple of starlings were also among the dead. Those species roost with blackbirds, particularly in winter.