by Dr. Sarah Treanor Bois
Director of Research & Education at the Linda Loring Nature Foundation
A mysterious bird illness has been plaguing songbirds in the eastern US this summer. The specific cause and mode of spread are still unknown, but it has been spreading. State and federal wildlife officials, researchers, and birders are concerned, and investigations continue to find a cause. With many breeding songbirds on-island, local conservation groups are keeping an eye out for the mysterious illness that has yet to be reported in Massachusetts.
This event began in the spring of 2021 with sick and dying birds being reported to wildlife managers in the mid-Atlantic. The main species affected have been Common Grackle, Blue Jay, European Starling, and American Robin, but other songbird species have been reported as well. It appears that juvenile birds are the most impacted; however, this disease has also been reported in adults. Reported symptoms include eye swelling, crusty discharge, neurological issues, seizures, and even paralysis.
The original states affected (Maryland, Virginia, West Virginia, Washington D.C., and Kentucky) sounded the alarm, encouraging reports to wildlife officials, and cleaning and removing feeders and bird baths in an effort to stop potential spread. More recently, reports have come from Delaware, New Jersey, Pennsylvania, Ohio, and Indiana.
The lethality, pervasiveness, and definitive cause of this disease remains unknown. Reports indicate that sick birds don’t respond to treatments. Scientists are calling it a “mortality event,” when animals die in a short period of time from what appears to be the same cause. One hypothesis is that the emergence of Brood X cicadas, which caused a diet change in songbirds, had unexpected health effects. Cicadas spend most of their lives underground, where they may have accumulated pesticides or other contaminants. A type of fungus called Massospora that infects cicada broods might also play a role. Scientists studying this event have also found that Mycoplasma bacterial infections have been prevalent among the dead birds. However, no explanations have yet to be found conclusive and researchers remain actively at work studying potential causes of this illness.
On July 15, the Massachusetts Division of Fisheries and Wildlife asked people to take down feeders and bird baths especially since the birds affected are primarily seed eaters. While the illness hadn’t been detected in New England, the preemptive move has been recommended in order to impede any potential spread.
On Nantucket, the Linda Loring Nature Foundation has announced removing their feeders from the LLNF offices and recommending others do the same following MassWildlife and Mass Audubon recommendations.
Recently, the Cornell Lab of Ornithology and the College of Veterinary Medicine came out as saying that the outbreak wasn’t as bad as the media is making it sound. While research continues on potential causes, songbird populations “remain stable.” That’s caused some bird enthusiasts to resume their regular feeding activity.
With so much unknown, however, a little proactive prevention could make a difference. Many people already stop feeding birds at this time of year. Feeding birds in the summer is more for people than for the birds themselves. Summer is the peak of the growing season. There are plenty of berries, nuts, and insects for our wild birds to eat. Taking feeders down for a few months while researchers figure out a cause won’t do any harm to bird populations. In fact, you may be helping reduce further spread of this unknown illness.
As of August 2, no large-scale mortality event has been reported in Massachusetts. However, in a July 30 update to the original announcement, Mass- Wildlife stated: “As the investigation continues in other impacted regions, MassWildlife is asking the public to continue to refrain from feeding birds and putting out bird baths at this time as a precaution to avoid any risk to spreading the mysterious illness.” The Linda Loring Nature Foundation is recommending Nantucketers continue to follow these recommendations.
As the “baby bird season” wanes, so have the number of reported incidences of the illness. One hypothesis is that incidences of the disease are tapering off because of fewer young birds which are more susceptible to the illness.
Alternatively, the tapering off of mortality is lending credit to the original hypothesis that the illness is related to the Brood X cicada emergence. The retreat of the cicadas coincides with the reduction of reported avian illnesses. The affected states also reflect the states where the cicadas were present.
As new information comes to light and researchers continue to investigate, local conservation groups recommend following the state guidelines.
Putting those feeders away and cleaning out bird baths doesn’t mean you can’t enjoy birds in your own yard. There are other, natural ways to attract birds without concentrating them at feeders. This article: yesterdaysisland.com/make-your-yard-a-paradise-for-birds/ discusses what to plant and how to create backyard habitat that birds can enjoy year-round. Many of these same suggestions work for pollinators as well.
The Linda Loring Nature Foundation will update their social media and website information in coordination with any MassWildlife updates. In the meantime, you can continue to report sightings of dead birds or birds displaying signs of illness using the MassWildlife online form. Until the outbreak ends, we can all do a little to keep our Nantucket birds as safe as possible.