For two months, a mysterious bird disease had been spreading across parts of the Mid-Atlantic and Southeastern United States, the Audubon Society reports.
Back in April, birds in the greater Washington, D.C., area began displaying strange symptoms. Their eyes were swollen and crusty, and some became disoriented, started twitching, and died. “They were having a hard time seeing,” says Nicole Nemeth of the Southeastern Cooperative Wildlife Disease Study (SCWDS) in Athens, Georgia. “Sometimes they don’t seem to be able to use their hind legs.”
By the end of May, similar reports were coming in from Maryland, West Virginia and Virginia. By June, more reports of potential disease turned up in Delaware, New Jersey, Ohio, Tennessee, Florida, Indiana, and Pennsylvania, according to the U.S. Geological Survey Wildlife Health Information Sharing Partnership. Thousands of sick and dying birds have been reported to SCWDS and other wildlife disease centers in nearby states.
Although SCWDS is one of several state and federal agencies, including the United States Geological Survey’s National Wildlife Health Center (NWHC), currently working together to diagnose the mysterious ailment, none have been able to identify the cause of the birds’ deaths so far.
Several common bird pathogens have been ruled out, including West Nile virus, avian influenza, Newcastle disease, herpesviruses, poxviruses, salmonella, chlamydia, and trichomonas parasites.
Some ecologists have speculated that since birds eat a lot of cicadas, it is possible that they also ingest the occasional mouthful a fungus that affects them, or get spores in their eyes.