The mysterious songbird illness that is blinding and killing songbirds in multiple states has now spread to Pennsylvania. Symptoms of the illness include a discharge and/or crusting around the eyes, eye lesions, and/or neurologic signs such as falling over or head tremors. No human health or domestic livestock and poultry issues have been reported.
The disease has been reported in 27 Pennsylvania counties in the following species: blue jays, European starlings, common grackles, American robins, northern cardinals, house finches, house sparrows, eastern bluebirds, red-bellied woodpeckers, Carolina chickadees, and Carolina wrens. Tri-State Bird Rescue and Research in Newark, DE has found that the disease primarily affects fledgling European starlings, blue jays, and common grackles.
In response to these events, the PA Game Commission (PGC) advised the public to remove feeders and bird baths to slow the spread. You can read the complete PGC statement here. Valley Forge Audubon Society urges the public to follow these 5 precautionary measures until more is known:
- Cease feeding birds and providing water in bird baths until this wildlife mortality event has concluded to prevent potential spread between birds and to other wildlife.
- Clean feeders and bird baths with a 10% bleach solution.
- Avoid handling dead or injured wild birds. Wear disposable gloves if it’s necessary to handle a bird.
- Keep pets away from sick or dead birds as a standard precaution.
- To dispose of dead birds, place them in a sealable plastic bag and discard with household trash. This will prevent disease transmission to other birds and wildlife.
The public also is encouraged to report any sightings of birds that have died and/or birds that have been seen with swollen and crusty eyes, as well as neurological signs such as stumbling and head tremors. Report the incident online at
The natural resource management agencies in the affected states and the District of Columbia, along with the National Park Service, are continuing to work with diagnostic laboratories to investigate the cause(s) of this event. Those laboratories include the United States Geological Survey (USGS) National Wildlife Health Center, the University of Georgia Southeastern Cooperative Wildlife Disease Study, the University of Pennsylvania Wildlife Futures Program, and the Indiana Animal Disease Diagnostic Laboratory.
On July 2, the USGS reported that a number of pathogens have NOT been detected in any birds tested. These include Salmonella and Chlamydia (bacterial pathogens); avian influenza virus and West Nile virus. You can read the complete USGS statement here. Testing is ongoing.
VFAS will be posting updates as they become available.
UPDATE (July 6 from the PGC):
As of last night, a total of 1,053 songbird mortality/morbidity reports were received through Wildlife Future’s “Bird Mortality Reporting Form” Of those, 1,011 were from PA, 42 were from 14 other states, plus one from India.
Reports received from PA include:
40 reports from 8 of the 10 Northcentral Region counties
97 reports from 12 of the 13 Northeast Region counties
33 reports from 7 of the 10 Northwest Region counties
154 reports from 12 of the 12 Southcentral Region counties
529 reports from 12 of the 12 Southeast Region counties
158 reports from 9 of the 10 Southweat Region counties
To date, the songbird morbidity/mortality event appears to be targeting fledgling common grackles, blue jays, European starlings, and American robins. Affected songbirds are presenting with eye swelling and crusty discharge, along with neurological signs. While an exact cause has not been identified and diagnostics are ongoing, the following pathogens have been ruled out: Salmonella, Chlamydia, avian influenza virus, West Nile virus, Newcastle disease virus, herpesviruses, poxviruses, and Trichomonas parasites.
Currently, this health event does not appear to impact mourning doves.
UPDATE (July 8 from National Audubon): https://www.audubon.org/news/scientists-still-searching-pathogen-behind-easts-songbird-epidemic
UPDATE (July 8 from the PGC): Wildlife Futures received 1,679 public reports through our WFP online bird mortality portal. This includes 1,525 unique bird reports in Pennsylvania. Here’s a breakdown Game Commission regions:
Reports received from PA include:
56 reports from 8 of the 10 Northcentral Region counties
135 reports from 12 of the 13 Northeast Region counties
60 reports from 8 of the 10 Northwest Region counties
233 reports from 12 of the 12 Southcentral Region counties
783 reports from 12 of the 12 Southeast Region counties
239 reports from 10 of the 10 Southweat Region counties
Among these Pennsylvania reports, they estimate that roughly 25-30% (approximately 500) are likely associated with the current songbird mortality event. To date, the songbird morbidity/mortality event appears to be targeting fledgling common grackles, blue jays, European starlings, and American robins. Affected songbirds are presenting with eye swelling and crusty discharge, along with neurological signs. While an exact cause has not been identified and diagnostics are ongoing, the following pathogens have been ruled out: Salmonella, Chlamydia, avian influenza virus, West Nile virus, Newcastle disease virus, herpesviruses, poxviruses, and Trichomonas parasites. There are no new developments on the diagnostics side, with multiple test results still pending at New Bolton Center and Penn State’s Animal Diagnostic Laboratory.
UPDATE (July 12 from the Smithsonian/National Zoo): 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.
UPDATE (July 16 from PA Department of Environmental Protection): The DEP is working with PA Game Commission and the Wildlife Futures program to triage appropriate reports. DEP has their system up and running for the reporting of dead birds through the West Nile virus website.
UPDATE (July 16 from Penn Vet Wildlife Futures Program): Since mid-May, numerous young birds – mainly blue jays, starlings, and common grackles, but also robins and cardinals – have been found with ocular and neurologic issues, and in some cases, these birds have been found dead in large numbers—up to 16 in one location.
At first glance (no pun intended) the eye lesions look similar to House Finch conjunctivitis caused by Mycoplasma gallisepticum (MG), with general swelling around the eyes and the lids often sealed closed with crusty discharge. Unlike finches with MG, the infection does NOT appear to extend into the sinuses but DOES appear to affect the eyes themselves: many have corneal lesions and uveitis (inflammation in the eye), some have hypopyon (pus inside the eye), and some have iridocyclitis (inflammation in the iris).
In addition, some (but not all) of the affected birds are showing neurologic signs consisting of head tremors, leg paresis, ataxia (falling to the side) or inability to stand at all, and excessive vocalizations. Also, most of the birds are in good body condition—likely still being fed by their parents.
Rehabilitation centers are seeing a mix of these presentations: some cases that are only neurologic, some that are only ocular, and some that are a mix of ocular and neurologic. In addition, the distribution of the mixture varies: some rehabilitation centers report that cases are mostly neurologic alone, some report mostly ophthalmic alone, and some report that most cases have both neurologic and ophthalmic signs.
MANY theories have been posed as to the etiology (cause) of this event. Though some preliminary findings suggest a bacterial infection, this has not been a consistent finding. Some have speculated that this could be associated with pesticides being used on the cicadas, while others suggest there may be a relationship to a neurotoxin produced by the fungus (Massospora cicadina) that is affecting some of the cicadas. Another theory is that the observed signs are associated with ingesting the cicadas themselves. It is important to note that NONE of these ideas has been confirmed or ruled out via diagnostics. Several possible viral causes have been ruled out, and toxicology tests are pending at three different laboratories. At this point, no one knows for certain if all the cases are truly related, with a single etiology, or if multiple things are occurring. Many diagnostic lab findings are still pending and nothing definitive across all the morbidities/mortalities has been identified.
What Can You Do if You Find a Dead Bird?
Double bag the birds; turn a plastic bag inside out and use it to pick up the dead birds, turning the bag right-side out in the process so that the bird(s) end up inside the bag. Then place that bag inside a second bag and seal the outer bag. Bagged birds should be kept in a cool area (on ice, but not frozen, if possible); wash hands well afterward. In Pennsylvania, contact the Wildlife Health Technician in your region (see below) and arrange for them to pick up the birds from you, or contact the Wildlife Futures Program directly.
Outside of PA, contact your state wildlife program (DNR, DEC, F&W, etc.) for specific instructions.
Contacting Wildlife Health Technicians in PA:
Northwest: Butler, Clarion, Crawford, Erie, Forest, Jefferson, Lawrence, Mercer, Venango, Warren; Lane Potts, (484) 667-7477.
Southwest: Allegheny, Armstrong, Beaver, Cambria, Fayette, Greene, Indiana, Somerset, Washington, Westmoreland; Luke Scherer, (610) 858-4444.
Northcentral: Cameron, Centre, Clearfield, Clinton, Elk, Lycoming, McKean, Potter, Tioga, Union; Ashley McDowell, (484) 667-7230.
Southcentral: Adams, Bedford, Blair, Cumberland, Franklin, Fulton, Huntingdon, Juniata, Mifflin, Perry, Snyder, York; Matt Shaub, (610) 858-3734.
Northeast: Bradford, Carbon, Columbia, Lackawanna, Luzerne, Monroe, Montour, Northumberland, Pike, Sullivan, Susquehanna, Wayne, Wyoming; Lauren Maxwell, (484) 280-3171.
Southeast: Berks, Bucks, Chester, Dauphin, Delaware, Lancaster, Lebanon, Lehigh, Montgomery, Northampton, Philadelphia, Schuylkill; Ian Gereg, (610) 858-2180.
UPDATE (July 19 from Penn Vet): https://www.vet.upenn.edu/about/news-room/news-stories/news-story-detail/the-search-for-the-culprit-behind-songbird-deaths
UPDATE (July 26 from the PGC): The Wildlife Futures Program’s (WFP) web portal, hosting the Songbird Mortality Report Form, will remain open through at least August 15th. The number of new reports has waned over the past week. Fewer than twenty percent of the 2,982 reports submitted from Pennsylvania through the web portal between July 1, 2021, through July 22, 2021, have been identified as being POTENTIALLY related to the songbird “mystery illness.” Poor condition of affected birds due to heat degradation, insect damage (maggots), and secondary predation has limited the number of usable specimens for analysis.
A total of 30 songbirds, representing submissions from all six Pennsylvania Game Commission regions, have been sent to the Pennsylvania Animal Diagnostic Laboratory System for full diagnostics. Tests for avian influenza, West Nile Virus, and Newcastle Disease Virus have all been negative. Other results are still pending. The WFP is partnering with other laboratories to accelerate the investigation and broaden the scope of diagnostic testing. To date, the cause of the songbird mortality event remains unknown.
The Pennsylvania Game Commission is recommending that people cease feeding birds until this event is resolved. There is no official moratorium.
UPDATE (July 28 from the Cornell Lab of Ornithology: “Over the course of weeks, no one was finding anything infectious,” Elizabeth Bunting, Senior Extension Associate at the Cornell Wildlife Health Lab said. “They did a lot of testing but could not come up with any disease process, and the rehabilitators were telling us they were trying antibiotics and things like that, but they did not have great effectiveness.”
Bunting said that the outbreak exhibits similar symptoms to mycoplasma, a bacterial infection that commonly afflicts finches, causing swollen eyes. However, this disease lacks the neurological components that accompany the unknown illness. Labs across the nation have worked to rule out many other possibilities including salmonella, avian influenza, and the West Nile virus.
This sudden decline lends support to the tentative hypothesis regarding a cause of the outbreak. The most recent working theory is that the outbreak is related to the emergence of the cicadas this year — the geographic distribution and the timing of the undetermined songbird illness directly coincides with the arrival of the cicadas.
The cicadas emerged in Washington, DC and eleven other states: Delaware, Indiana, Ohio, Pennsylvania, New Jersey, Maryland, West Virginia, Virginia, Tennessee, Florida, and Kentucky in mid May. Birds in these states started showing unusual symptoms about a week later. The distribution of states where this spontaneously popped up was an exact match for the cicada emergence map, and it is a very strange distribution of states for this kind of outbreak. It was Virginia, West Virginia, Maryland, Delaware, New Jersey, Pennsylvania, and then it moved over to Tennessee, Kentucky, Ohio, Indiana but it completely skipped New York and the rest of New England. That is an exact replica of the cicada map.
Researchers believe that the ingestion of the cicadas could have had toxic effects on the birds. It is possible that individuals sprayed the cicadas with pesticides, which have chemicals that affect the brains of birds and could have caused the neurological symptoms. Cicadas also carry fungi that can produce toxins when ingested which could have also produced the illness in the birds.
The decline in cases corresponds with the retreat of the cicadas. Although researchers will continue to monitor the situation, Bunting expressed that the outbreak should not be a cause of alarm. The diminishing outbreak does not pose any safety threats to humans, nor does it threaten the stability of the various songbird species.