Report: 'Blunt force trauma' killed birds

From UPI:

LITTLE ROCK, Ark., Jan. 27 (UPI) -- The Arkansas Game and Fish Commission says "blunt force trauma" killed thousands of blackbirds northeast of Little Rock.

Officials made their determination after examining the remains of 13 red-winged blackbirds that were part of the group that flew into buildings and died in Beebe, Ark., CNN reported Thursday.

"The tests ruled out bacteria, viruses, heavy metals, pesticides and avicides (chemicals used to kill birds) as causes of death," the commission said in a statement.

The commission said tests found hemorrhaging "consistent with blunt trauma. In most instances, such traumatic injuries in wild birds are due to flying into stationary objects such as trees, houses, windows, power lines, towers, etc."

About 5,000 birds died in the incident, which occurred several days before another incident in which about 500 birds were found dead about 450 miles south of Little Rock.