Wildlife experts are monitoring a scary mystery affliction that is leaving birds blind and dying.

Since the start of this June, the Ohio Wildlife Center identified multiple cases of an unknown illness in songbird species across Central Ohio, but the disease has also been identified in other states like Virginia, Delaware, Maryland, Indiana, and West Virginia.

The symptoms include a white crust in birds’ eyes that leads to blindness, and damage to their nervous system, rendering them unable to fly.

“So we’re not seeing it in our ducks, and we’re not seeing it in our hawks, but we do see it in birds like crows or birds like morning doves,” said Stormy Gibson, interim executive director for the Ohio Wildlife Center.

On June 9, the U.S. Geological Survey issued a statement saying that the USGS, along with a number of park and wildlife groups, are investigating after officials in Washington D.C., Maryland and West Virginia started receiving reports of “sick and dying birds with eye swelling and crusty discharge” in late May.