A bacterial or fungal infection might have caused as many as 2,500 mallard ducks to die in a bizarre cluster along an Idaho creek bed, a state game official said.
Preliminary test results suggested the possibility of infection, but more tests are planned on water and grain in the area, said David Parrish, supervisor for the Magic Valley region of the Idaho Department of Fish and Game.
Idaho and federal officials, including a representative of the Homeland Security Department, conferred by conference call late Thursday.
Parrish declined to say specifically what was discussed, but did not rule out the possibility that more ducks might die in the area.
"We may have a few more, but that's a little difficult to predict right now until we can determine the exact cause of the mortality," he said.
He said the die-off was not typical. "It's fairly uncommon, especially in these types of numbers and in such a confined area," he said.
The ducks mysteriously began dying last week around Land Springs Creek, near the remote town of Oakley, about 180 miles (290 kilometers) southeast of Boise.