When Brian Evans heard about young birds dying at a high rate this spring, he dismissed it. The bird ecologist at the Smithsonian Migratory Bird Center in Washington, D.C., knew most hatchlings don’t survive to their first year, he tells Natasha Daly of National Geographic.
However, Evans took notice when a neighbor told him about a sick bird she had seen. It looked like it was blind, shaking and nonresponsive. Something clicked when he heard her description.
“That’s not your typical dying fledgling,” he tells National Geographic.
Evans was correct. What his neighbor witnessed was the early days of a mysterious disease that has been killing songbirds in several mid-Atlantic states. Now, the illness is spreading to other regions. Scientists in 11 states and Washington, D.C., are trying to determine what is killing thousands of young blue jays, grackles, starlings and robins, as well as other birds.
Two weeks ago, the mysterious disease was discovered in Kentucky. On July 15, the Massachusetts Division of Fisheries & Wildlife asked residents to peremptorily take down bird feeders and birdbaths, though the illness is not believed to be in New England yet, reports WWLP Digital First.
Little is known about the disease at this stage. Scientists are calling it a “mortality event,” when animals die in a short period of time from what appears to be the same cause. Symptoms are similar to Mycoplasma gallisepticum, a bacterial infection that sickened house finches with crusty and swollen eyes in the 1990s. However, that illness did not include a neurological component, Evans writes in a report first posted June 29 and updated July 12.
“We’re seeing birds exhibit distressing symptoms, including problems with their eyes and possibly their nervous systems,” he writes. “Many birds have been found blind and/or with crusty eyes. They often appear on the ground, confused, with shaky heads, and are sometimes lethargic or unresponsive.”
In addition to Washington, D.C., dead birds with similar symptoms have been discovered in Maryland, West Virginia, Virginia, Delaware, New Jersey, Ohio, Tennessee, Florida, Indiana, Pennsylvania and Kentucky.
Researchers are baffled by the mystery illness. So far, they have ruled out a number of possibilities, including salmonella, chlamydia, avian influenza, West Nile virus, various herpes viruses and other diseases.
Scientists are even investigating if this spring’s eruption of 17-year cicadas is related. The insects are known to carry a pathogenic fungus, though no connection has been established with the bird disease, Allysin Gillet, an ornithologist with the Indiana Department of Natural Resources, tells Bente Bouthier of Indiana Public Media.
“No direct link has been made between those two,” she says. “We’re also seeing that the regions that are seeing more reports are a bit outside the range of that Brood X Cicada.”
Diagnosing the illness is an involved process. Several state and federal agencies, including Southeastern Cooperative Wildlife Disease Study (SCWDS) and the United States Geological Survey’s National Wildlife Health Center, are working together to solve the mystery. With so many diseases, pathogens, fungus and toxins to consider, there is an endless list to review, Nicole Nemeth of SCWDS tells Joanna Thompson of Audubon Magazine.
“There’s really still a lot of possibilities,” she says. “Unfortunately, it just takes time.”
In the meantime, Evans is reaching out to the public for their help. People who find an injured, sick or dead bird are asked to complete a brief online questionnaire for the Smithsonian's National Zoo and Conservation Biology Institute. This data could be crucial in finding a cause.
“The information you submit—date, location, bird age, species (if you know it), and a photo—will help us understand the scope of this event,” Evans says.