Hundreds of birds have dropped dead from the sky in Louisiana just days after a similar mysterious incident left scientists baffled in Arkansas.
The carcasses of around 500 red-winged blackbirds were found littering a quarter-mile stretch of road in Pointe Coupee, The Advocate reported.
The state borders Arkansas where some 3,000 blackbirds died in unexplained circumstances three days ago.
The remains of some of the birds found dead in Louisiana are being taken away for testing.
A woman several hundred miles away in Kentucky has also reported finding dozens of dead birds in her garden.
The mass deaths in Beebe, Ark, Arkansas, have puzzled scientists and wildlife experts.
Witnesses reported seeing the birds falling from the sky late on December 31 into early January 1.
Around 100,000 fish were also found dead along a river 125 miles away although scientists are not linking the cases.
Officials are looking at various possibilities as to why the birds dropped dead – including being startled by fireworks, stress or hit by hail or lightning.
Tests on the birds found in Arkansas showed they suffered internal injuries that formed blood clots leading to their deaths, The Associated Press reported.
US scientists believe New Year’s Eve fireworks may have forced the birds to fly low to avoid explosions, leading them to collide with objects.
High winds and tornadoes also struck Arkansas on December 31, with the hardest-hit area more than 150 miles to the west of Beebe.