Thousands of black birds that fell from the sky and landed dead in Arkansas on New Years Eve likely died from massive trauma, according to a preliminary report released Monday by the Arkansas Livestock and Poultry Commission.

According to Keith Stephens, a spokesman for the Arkansas Game and Fish Commission, "the birds showed evidence of trauma in the breast tissue, blood clots in the body cavity and a lot of internal bleeding." 

Karen Rowe, an ornithologist for the commission, said the incident could have been caused by a lightning strike. A storm had ripped through the area on Friday. Officials were also trying to determine whether New Years Eve fireworks that went off in the area could be to blame.

Said Rowe: "The birds obviously hit something very hard and had hemorrhages."

Up to 5,000 birds died as of Saturday. They were discovered about 40 miles northeast of Little Rock.

MSNBC has pictures of the dead birds here and CNN has video here.