Wildlife experts are trying to determine what’s killing hundreds of birds in six states.  Birds are mysteriously dying in Kentucky, Indiana, Maryland, Ohio, Virginia, and West Virginia. The Cincinnati Enquirer points out it has been found in “Blue Jays, Common Grackles and European starlings, American Robins and potentially House Sparrows.”

USA Today spoke with Laura Kearns, a wildlife biologist with the Ohio Division:

Kearns said not all birds have the same exact symptoms, but one thing is common: physical changes around the eyes.

“Some report crustiness around the eyes, some report like bulging or swollen eyes. And then we’ve also had reports of the eyes being kind of sunken in,” Kearns said.

She added the birds also show neurological symptoms like not being able to keep their heads up or are uncoordinated, saying, “they just kind of seem disoriented.”

Jim Monsma from the wildlife rescue organization, City Wildlife says the first case surfaced on April 11th. He told NPR, “This is truly scary… We don’t see the light at the end of the tunnel, as it were, yet. And it’s just every day more and more birds.”

None of the birds have tested positive for bird flu. One theory floating around is that the birds may be eating cicadas that are infected with a fungus, but some of the birds are in areas where cicadas aren’t present.

The National Wildlife Health Center is recommending people in the impacted states remove their bird feeders until this is resolved.

Watch more above from the NBC affiliate in Columbus, Ohio.