La. has mass bird kill just days after Ark.

BEEBE, Ark. (AP) -- Blackbirds are having hard time staying alive in the Southeast.

Just a few days after 3,000 blackbirds fell from the sky in Arkansas, about 500 birds dropped to their death in Louisiana, littering a quarter-mile stretch of highway near Baton Rouge. It wasn't clear if the deaths were linked, but such massive wildlife kills are far from uncommon.

Biologists were trying to figure out what killed the birds in rural Pointe Coupee Parish, La. About 300 miles to the north, in the small town of Beebe in central Arkansas, scientists said celebratory fireworks on New Year's Eve likely sent thousands of discombobulated blackbirds into such a tizzy that they crashed into homes, cars and each other before plummeting to their deaths. Still, officials acknowledged it's unlikely they'll ever pinpoint a cause with certainty.

Wildlife officials in both Arkansas and Louisiana were sending carcasses to researchers at the National Wildlife Health Center in Madison, Wis. and the University of Georgia, but it's not clear the bird deaths were related.

In Beebe, New Year's revelers spent the holiday weekend cleaning up between 4,000 and 5,000 dead red-winged blackbirds. Some speculated that bad weather was to blame. Others said one confused bird could have led the group in a fatal plunge. A few spooked schoolkids guessed the birds committed mass suicide.

"There was probably some physical reason, but I doubt anyone will ever know what it was," said Thurman Booth, the state's wildlife services director.

The birds were the second mass wildlife death in Arkansas in recent days. Last week, about 83,000 dead and dying drum fish washed up along a 20-mile stretch of the Arkansas River, about 100 miles west of Beebe. Wildlife officials say the fish deaths are not related to the dead birds, and that because mainly one species of fish was affected, it is likely they were stricken by an illness. Full test results could take up to a month.

The U.S. Geological Service's website lists about 90 mass deaths of birds and other wildlife from June through Dec. 12. Five list deaths of at least 1,000 birds and another 12 show at least 500 dead birds.

The largest was near Houston, Minn., where about 4,000 water birds died between Sept. 6 and Nov. 26 from infestations of various parasites.

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, N.Y.