The mystery of the dying birds deepened for baffled experts after another 500 birds were found littering a Louisiana highway days after 5,000 redwinged blackbirds plunged to their death on New Year's eve.
Just 300 miles away from Beebe, Ark., where thousands of dying birds fell from the sky this past weekend, Louisiana officials revealed that hundreds of birds were found dead Monday.
"We have blackbirds, starlings, sparrows. Several species of birds are affected," said Dr. Jim Lacour, Louisiana's state wildlife veterinarian.
The birds were found in the Labarre community, 30 miles from Baton Rouge. Officials say that the two incidents are pure coincidence and unrelated to one another.
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Louisiana officials believe the birds fell to their death either late Sunday or early Monday after flying into a power line. The birds sustained injuries from broken beaks to broken backs. What prompted the birds to fly into the power line, however, is still a mystery.
Dan Cristol, co-founder of the Institute for Integrative Bird Behavior Studies at the College of William & Mary, told the Associated Press that the Louisiana birds may have been ill or startled from their roost, then hit the power line.
"They don't hit a power line for no reason," Cristol said.
The bigger mystery remains the mass death of 5,000 redwing blackbirds in Beebe, Ark.
911 Calls Reveal Confusion Over Dead Arkansas Birds
Newly released 911 calls reveal the initial confusion people felt at the site of birds littering their roads, yards and roofs.
"They are like bleeding out of the mouth and some of them are not dead. I think they have been poisoned," one Arkansas caller said.
Another caller asked, "I was wondering why all the birds, are just like, dying?"
Officials say they may never know for sure what caused such a large number of birds to die at once. It is very unusual for redwing blackbirds to fly after dark, because they have poor night vision.
"This is probably the biggest amount that died in all one small area, one square mile, that there's ever been in Arkansas," George Badley, Arkansas state veterinarian, said.
What officials know for sure is that the birds died from trauma. According to preliminary testing, the trauma was primarily in breast tissue, with blood clots in the body cavity and internal bleeding. All major organs were normal and the birds appeared to be healthy, the tests found.
"Almost every one of them ... had multiple internal hemorrhages which would mean that it was trauma, not a disease process. Their stomachs were empty, which would rule out toxicity from eating some kind of poison grain," Badley said.
Officials have blamed the New Year's Eve fireworks for startling the birds and forcing them to plunge to their death.
Still, some think disease or bad weather could have played a part.
"It's conceivable that this mass suicide was sparked by an atmospheric disturbance... it's also a possibility of a microburst," said Dr. Michio Kaku, author of "Physics of the Future."
Scientists said that mass bird deaths are not uncommon.
The U.S. Geological Service's website listed about 90 mass deaths of birds and other wildlife from June through Dec. 12. There were five incidents of at least 1,000 birds. Between Sept. 6 and Nov. 26 of last year, 4,000 water birds died near Houston, Minn.
In Arkansas alone, lightning killed ducks at Hot Springs in 2001 and hail knocked birds from the sky at Stuttgart in 1973 on the day before hunting season.
The Associated Press contributed to this report.