Update July 12, 2021: The cause of the bird mortality event remains a mystery. At the Smithsonian's National Zoo and Conservation Biology Institute, our scientists, veterinarians and avian experts continue to try to find out what is harming these birds. Laboratories around the country are testing birds for evidence of disease or exposure to toxins. Several diseases, including West Nile virus, avian pox and bird flu (avian influenza), have not been found in the birds that have been tested.
From what we know so far, it is unlikely that the emergence of Brood X cicadas contributed to this mortality event. While the event largely had the same timing and distribution as the arrival of the cicadas, it also appears to be happening in areas without cicadas or in places where cicadas emerged but are now gone.
Testing has shown that many of the birds have an infection caused by a bacteria called Mycoplasma. Disease caused by Mycoplasma can be highly transmissible and has been a problem for birds in the past. House finch populations were hit especially hard by a Mycoplasma outbreak that began in the 1990s. However, the neurologic symptoms associated with this current bird mortality event are not entirely consistent with Mycoplasma infection. It is becoming clear that there is something else going on, the cause of which is still unknown.
What should I do after submitting a bird report to the Zoo?
After submitting your report to the Zoo, you'll also be asked to report your injured or dead bird to your state’s reporting form (when available). Several states, including Virginia, have reporting systems in place. If you found a live bird, you'll be directed to contact your local wildlife rehabilitation center. Please do not touch birds prior to receiving instructions from your local wildlife rehabilitator or state wildlife agency.
In late April, scientists and the public noticed something odd about the birds in the mid-Atlantic region — a surprising number were exhibiting strange symptoms, such as crusty eyes or shaking heads. The birds were often sick or dying. Smithsonian scientists need your help to figure out why.
Citizen science can play a crucial role in helping solve the mystery of what’s happening to these birds. The data you collect can help Smithsonian Migratory Bird Center scientists get a handle on the scope of this event. Please report the injured or dead birds that you see in your neighborhood. Read on for more information.
What is happening to these birds?
This is something we as scientists refer to as a mortality event — when a large number of animals die in a relatively short period of time due to what appears to be a common cause. We’re seeing birds exhibit distressing symptoms, including problems with their eyes and possibly their nervous systems. 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.
What species of birds are affected?
We’re seeing this across several species of your typical backyard birds: mostly blue jays, common grackles, European starlings, American robins; but also Carolina wrens, gray catbirds, house sparrows, northern cardinals and northern flickers.
So far, it’s been mostly juveniles, but we’re also seeing it in adult birds.
Where is this happening?
Right now, it seems that birds in the mid-Atlantic region are hardest hit. But similar cases have been reported across the country, including Florida, Ohio and other states.
When did this start?
To the best of our knowledge, birds mysteriously started falling ill and dying in April 2021. It seems to have peaked in early June in the mid-Atlantic. We see some indications that the bird deaths are now declining — or at least fewer birds are being brought into local wildlife rehabilitation centers. But it’s still too early to really tell.
What’s killing these birds?
At this time, the cause remains entirely a mystery, and we’re still collecting data and exploring a number of potential causes.
When there’s not an obvious cause for something like this, we typically look for ways the environment may have changed. And what’s different this year is the cicadas.
Could these bird deaths be linked to the 17-year Brood X cicada emergence? There are a few different ways the cicadas could have caused mass bird death.
Many songbirds in our region ate a lot of cicadas in May and June. When birds eat a lot of cicadas, they are essentially exposed to high levels of whatever is in the cicadas. So, even low levels of toxins in the cicadas are magnified when a bird eats hundreds (or even thousands) of them. These toxins can come from fungus, pesticides, or anything else in the environment over the span of the past 17 years that the cicadas were underground.
If these bird deaths are not linked in any way to the cicadas, then we’re going to have to dig a lot deeper. But because this didn’t happen last year or the year before, the cicadas are a good place to start looking for answers.
How can I help?
For now, per U.S. Geological Survey (USGS) guidance we’re asking everyone to take down and clean their bird feeders and birdbaths in case these deaths are linked to a contagious disease.
Be a citizen scientist. If you find a sick or dying bird, we need you to report it. We’ve set up this online form with a few questions so that we can collect more data on live and dead birds. If you’ve found a live bird, please complete the form. After, you’ll be directed to your local wildlife rehabilitation center for more instructions.
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.