Updated August 13
In mid-July, the Massachusetts Division of Fisheries and Wildlife reported an unknown disease was circulating among songbirds in various parts of America: Washington, D.C., Maryland, Virginia, West Virginia, Kentucky, Delaware, New Jersey, Pennsylvania, Ohio. The disease was said to cause symptoms of “eye swelling and crusty discharge, as well as neurological signs.” The disease was not found in Massachusetts so far. However, the disease has reached Connecticut, according to the Hartford Courant.
The Ithaca Times reported on July 28 that experts from Cornell University are not “overly alarmed” by the unknown disease. Elizabeth Bunting, senior extension associate at the Cornell Wildlife Health Lab, said a possible cause of the disease is from the cicadas of Brood X. The songbirds who ate these cicadas may have gotten sick from pesticides sprayed on the cicadas, or fungi that the insects might be carrying. The pesticides may be causing neurological issues, and the fungi could be the cause of crusty eyes. Bunting said the locations where the disease was found are areas where the cicada broods emerged. Additionally, the decrease in cases of the mystery disease has accompanied “the retreat of the cicadas.” The disease was also not found in New York. New York and New England both did not have the massive number of cicadas some other states had.
“Information coming out of the National Wildlife Health Center and some of the other states said that the cases were declining all of a sudden,” Bunting told the Ithaca Times. “That would not be typical of an infectious disease outbreak. You wouldn’t expect an infectious disease to just spontaneously go away.”
Matt Pelikan, a Martha’s Vineyard naturalist and a columnist for The Times, said the correlation between the disease’s outbreak and the appearance of cicadas seemed like a strong one. However, nobody really knows what mechanisms actually caused the disease. “Though unproven, it is certainly plausible,” said Pelikan of Cornell’s hypothesis.
Pelkian thinks the mystery disease’s risk to Martha’s Vineyard is low, but not zero. “The pesticide problem should not be a risk on the Vineyard, since we have no periodical cicadas, nor any other insects that become hyperabundant like that. But if there is a fungus involved, infected birds could conceivably carry that part of the condition to M.V.,” said Pelikan.
Pelikan also said that birds’ migratory pattern tends to be southward at this time of year, so infected birds are more likely to remain away from the Island.
The Massachusetts DFW released an update on July 30 asking people to continue refraining from feeding birds or putting out birdbaths at this time as a precautionary measure against the disease. The DFW is still investigating the situation, and asks the public to send the department information about dead birds. Pelikan agrees with the DFW’s statement, and said birds do not need supplementary food at this point in the season. This will help reduce the amount of interaction among birds, to prevent and mitigate the disease from possible spread.
“If we’ve learned one thing from COVID, it’s that the time to take measures to stop the spread of a disease is before it gets established, not after,” said Pelikan.
Researchers across the country will continue to monitor the mystery disease’s development.