Last May a mysterious illness that affected songbirds suddenly appeared in the eastern states. By the time the illness finally abated, it had killed thousands of birds in the District of Columbia, Delaware, New Jersey, Virginia, Pennsylvania, Kentucky and West Virginia. This prompted state wildlife agencies and conservation groups, to urge the public to cease providing wild birds with water or food. Then, for some unknown reason, the songbird illness suddenly disappeared this past July.
The birds affected by the outbreak displayed the same symptoms: swollen, crusty eyes, paralysis, are tremors.
The birds that were most affected were young common grackles, blue jays and European starlings. However, the roster of birds that showed symptoms of the disease included Carolina wrens and chickadees, red-bellied woodpeckers, eastern bluebirds, American robins, house finches, northern cardinals, and house sparrows.
The outbreak prompted the Cornell Wildlife Health Lab and the National Wildlife Health Lab, as well as wildlife disease labs across the country, to try to diagnose the cause of the illness. Their efforts methodically ruled out all of the known wildlife illnesses. This left them at a loss to explain what was causing the problem.
However, the scientists found the sudden appearance and decline of the disease closely mirrored the Brood X cicada emergence. This leads many of the scientists to theorize that mysterious bird illness that plagued birds across a vast swath of the east this past summer is linked to the cicadas. According to this theory birds may have been affected the cicadas in a number of ways. For example, they could have eaten cicadas poisoned by homeowners trying to eliminate the insects from their yards. Some birds may have also become sick from eating the cicadas themselves. It is also possible that a toxin produced by a fungus commonly found on cicadas could have poisoned the birds.
While this theory seems plausible, more research is needed before wildlife disease experts will definitively say this was indeed the cause of the problem.
In the meantime, many states have lifted bird-feeding restrictions implemented during the outbreak. However, they are urging that homeowners keep their bird feeding areas and feeders clean. While we were fortunate that the mysterious songbird illness did not crop up in Georgia, we should all strive to keep our bird feeders and the ground around them clean.