INDIANAPOLIS (AP) — Investigators still don’t know what’s killing songbirds around Indiana and other states — and, experts say, they may never find out.
Researchers started receiving reports of sick songbirds in June. While at first the birds were just found in a handful of counties, reports of the illness quickly spread to more than 70 counties in Indiana and in nearby states.
In the last months, Hoosier birders and bird enthusiasts took down their bird feeders and brought in their bird baths in hopes of stemming the spread of the illness.
In August, the state Department of Natural Resources announced that people could bring their feeders back except for in 13 counties, which include Marion, Hamilton, Hancock, Hendricks and Johnson counties.
IndyStar spoke with State Ornithologist Allisyn Gillet about what investigators know so far, and what more they’re doing to understand about why songbirds are dying. While the investigation is moving forward, she said it may still be some time before experts know what’s causing the illness. If at all.
“We still don’t have any conclusive results regarding the cause of this mortality and morbidity event, mainly because the tests are taking a long time,” Gillet said. “We might never really actually get to a conclusive cause.”
Here’s what you need to know about the illness killing songbirds in Indiana.
The affected birds are showing neurological signs of illness. This includes tremors and stumbling, as well as weakness and lethargy. Many of the birds are also exhibiting swelling and crusty discharge around their eyes.
The illness appears to be primarily affecting songbirds. Commonly affected species include: blue jays, American robins, common grackles, Northern cardinals, starlings, and brown-headed cowbirds.
About 500 sick birds have been found in Indiana, Gillet said, but the amount of affected birds across the country numbers in the thousands.
Birds with these symptoms have been found in Ohio, Kentucky, Virginia, Maryland and Pennsylvania.
The DNR has narrowed down priority pockets of this songbird illness to 13 counties in Indiana, which include: Allen, Carroll, Hamilton, Hancock, Hendricks, Johnson, Lake, Marion, Monroe, Porter, St. Joseph, Tippecanoe and Whitley.
Researchers were able to isolate these priority areas after a few months, Gillet said, because they noticed the majority of reported sick birds were coming from these counties, which happen to center around urban areas.
Gillet thinks the concentration around urban areas might be in part because of a sampling bias — there are just more people to report sick birds in these areas — but also because there may just be more songbirds in this area.
The types of birds being found sick — such as robins, common grackles and European starlings — are species that frequent urban environments. In these areas, there’s also likely a higher number of people feeding birds at bird feeders, which could spread the illness if it is a disease, she said.
While the dying and sick birds are showing the same symptoms, the symptoms don’t offer a clean explanation as to what is causing the sickness.
It’s like visiting a doctor for a runny nose, Gillet said: It could be caused by a cold, but it could also be from the flu or allergies.
And when it comes to the neurological symptoms shown by these songbirds, the list of possible causes is long. This means investigators are testing for a wide range of diseases, parasites, pathogens and exposures.
It’s also possible that the illness is being caused by a combination of factors rather than one cause, Gillet said, which adds a layer of complexity to the process.
“It might very well be that it’s a complex array of things that have caused the symptoms that we cannot tease apart,” Gillet said. “We don’t know if there will be an end to the investigation.”
So far, researchers have received negative test results for avian influenza, West Nile virus, salmonella, chlamydia, Newcastle disease virus, herpesviruses, Trichomonas parasites and other conditions. The investigators will be also looking into whether exposure to pesticides or vitamin deficiencies play a role.
Almost 100% of the birds who show the symptoms of this illness die from it, Gillet said.
While a rare few may have been nursed back to health by wildlife rehabilitators, she said, overall almost all of the affected birds are dying.
“It’s unfortunate, but usually birds do not end up surviving after they get these symptoms,” Gillet said. “The likelihood of them dying is extremely high.”
The DNR has said there is no threat to people from this illness, and that it will not affect the overall population of birds or specific bird species in Indiana.
While this songbird illness event is widespread, it’s not unprecedented. Gillet said notable diseases have also affected Indiana birds in the past.
House finch conjunctivitis, for example, started in the eastern U.S. in the early ’90s and spread its way to Indiana in the 2000s. And there is still the presence of West Nile virus in Indiana birds, a disease that also started in the eastern U.S. and spread westward to Indiana.
West Nile virus is monitored by the Centers for Disease Control and Prevention, because it can also be transmitted to humans and has the potential to create inflammation in peoples’ brains and spinal cords. As of August 2021, there were no known human infections.
Brood X, one of the largest emergences of the 17-year cicadas in the country, reached peak emergence in June, just a few weeks before the flood of reports of sick and dying songbirds.
Though the cicada emergence has ended, researchers are still evaluating whether they played a role in songbirds’ deaths. Gillet said that investigators are testing cicadas in the laboratory to see whether they could have been contaminated with pesticides or other materials that would have harmed the birds that ate them.
There have been several rumors circulating about the songbird illness.
A common myth is that the expansion of 5G — a high-speed wireless internet network — caused the birds to die.
There’s no evidence that that is the case, Gillet said. It seems highly unlikely, she said, given that 5G has expanded across the entirety of the U.S., but birds have only been dying in certain states. There would also be no reason for the illness to only affect songbird species, rather than all birds, if it were caused by 5G.
“There’s no scientific evidence to prove that that particular system has any effect on bird biology,” Gillet said.
Another myth posits that it’s being caused by genetically modified bird seed or bird seed in general: If that were the case, Gillet said, the illness would be found in all birds, and in every area where the birdseed is being used.
A rumor that the birds were infected by COVID-19 has also been disproved, Gillet said, as tests for the disease in the birds have come up negative.
Researchers have noticed a gradual decrease in the illness spreading.
But for now, the investigation continues. Indiana’s DNR and Animal Disease Diagnostic Laboratory is working with other state natural resources agencies through an interagency group run out of the National Wildlife Health Center, Gillet said. These members meet to discuss tracking, testing and any breakthroughs on this investigation.
One silver lining out of this incident, Gillet said, is that she and others at the DNR have learned just how much people love birds, with reports and messages of concern flooding in over recent months.
“They have a lot of emotional connection to them,” she said. “It’s just heartening to know that that’s the way people can connect to nature.”
Gillet says she hopes this illness will remind people to be good about bird bath and bird feeder hygiene and the importance of reporting illnesses to aid with bird conservation.
What can Hoosiers do to help?
If you live in Allen, Carroll, Clark, Floyd, Hamilton, Hancock, Hendricks, Johnson, Lake, Marion, Monroe, Morgan, Porter, St. Joseph, Tippecanoe or Whitley County, the DNR asks that you keep your bird feeders and bird baths inside for now.
But if you miss watching birds feed outside of your window, you may still have one option for providing food for them in your yard: plant native plants.
Native plants can be food for birds, or provide habitats for their food, if they eat insects. These plants are also excellent habitats for pollinators such as bees and butterflies, which have been facing substantial population loss in recent decades due to decreased habitat and food.
“It’s really quite lovely to watch birds actually forage on native plants, because they exhibit more natural behaviors,” Gillet said. “Planting native in your yard not only benefits the birds that eat the seeds from the plants ... but also a whole variety of other species.”
If you don’t live in one of these counties, you should still be practicing bird hygiene, Gillet said. You can do this by cleaning your bird feeders and bird baths with a 10% bleach solution every two weeks.
For most recent information about the songbird illness investigation, check online at the DNR’s website here.