Published July 19, 2021 at 10:03 AM EDT
Wildlife management officials are trying to find out why birds across the mid-Atlantic are becoming sick and dying.
Original reports found birds in parts of West Virginia and other states experiencing eye swelling and crusty discharge, as well as neurological signs including tremors.
Wildlife officials recommended removing bird feeders as they suspected that was how the illness is spreading. But now that idea is coming into question.
Eric Douglas spoke with Ethan Barton, the wildlife disease specialist for the West Virginia Division of Natural Resources by Zoom.
This interview has been lightly edited for clarity.
Douglas: We've been hearing a lot of these reports that started in what was mostly the Eastern Panhandle, Maryland and Northern Virginia. But now it seems like it's spread up to Wisconsin and Missouri and across Kentucky. Do we have any idea yet what's going on?
Barton: Not yet. Our first reports in West Virginia were in Berkeley and Jefferson counties at the beginning of June. At this point, we’ve had reports of somewhere between about 100 and 150 bird deaths with not all of those being related to this. So far, the bulk of the reports have still come from Berkeley and Jefferson counties. There's been a wide range of mortality that's been reported, but few large events seem to be related to this. So we've got a lot of ones and twos and threes. Still primarily young birds, with inflammation around eyes, crusty discharge around eyes, and similar species that the other states have been seeing — robins, grackles, European Starlings. We're still working with diagnostic labs and with partner agencies like the USGS (U.S. Geological Survey) and other state agencies.
The latest news to come out is that this does not seem to be viral in origin, at least not a known virus. And there have also been some tests for salmonella, chlamydia, trichomonas, which is a parasite, and all negative.
Douglas: You said 100 to 150 bird deaths in West Virginia. It’s in multiple states, but I assume the numbers are relatively small in all of those as well.
Barton: I don't think any of the other states have seen large scale mortality events. And it does seem to be a lot of penny packets — ones, and twos and threes at a given location.
Douglas: Is it because they're birds and they die in places where people aren't? Or is it just that it's just a really small incident?
Barton: At this point, in terms of scale, it's hard to put your finger on exactly how many birds are going to be involved. There was larger press involvement, and we see this with wildlife diseases, that people who are not well-versed in these things will suddenly start calling to report any dead bird they find — not necessarily just ones that are exhibiting the clinical signs. So it seems to be relatively widespread, but the actual mortality seems to be pretty diffuse and relatively low intensity.
Douglas: You don't think there are millions of birds falling out of the sky, but it's still something to be concerned about.
Barton: Yeah, that doesn't seem to be the case. The interesting part here is the really heavy involvement of younger birds. Younger birds don't have a fully-developed immune system yet. They're not going to be able to respond to a parasite or pathogen that may be innocuous to an adult bird. At this point, it doesn't seem like it's something as serious as say avian botulism, where you may find thousands of waterfowl dead in the same wetland.
Douglas: You seem to be talking about the larger song birds, the grackles, robins and blue jays.
Barton: Most of our reports have been those starlings, grackles, robins. We have had a few others like yellow billed cuckoo, and some other states have observed that as well. We weren't actually able to get good specimens of those to ship to the lab. The ones that had been found were pretty rotted up. And that's true when investigating avian mortality events, especially with small birds in the heat of the summer, little birds go bad, awfully fast.
Douglas: You talk about what it isn't. Do you have any possibilities of what is causing the problem?
Barton: Other states and ourselves, we started to get our first reports around the time that the 17-year brood 10 cicadas were starting to emerge. So I think the Smithsonian and a few others have floated some possible relationships there.
Douglas: The good news is the brood 10 cicadas are pretty much done now, right?
Barton: If it is cicada related, we and the other states around us should be seeing that subside pretty quickly. We have sent some of the brood 10 cicadas from West Virginia. I know Virginia collected a number and sent them. I think some other states did too, trying to run some toxicology on them. Thus far there's not been a whole lot of support for the idea and given the results, it doesn't seem to be toxin related. So far, they’ve been relatively clean.
But we're thinking that probably what's going on here with young birds being primarily the ones that are involved is that this may be multifactorial. We're doing our best to keep up with public calls, trying to triage those out, figure out what's related, what's not related, making records, identifying the species and then shipping out specimens as we can to try to get to the bottom of what's going on here.
Douglas: The fact that it's probably not viral means that it's probably not being transmitted at bird feeders and bird baths. But I assume for the short term, the recommendation is still to not feed for the summer.
Barton: Especially in those affected counties and the other counties in West Virginia, we've recommended that people think about good feeder hygiene. Best practice for bird feeders is that they should really be taken down and thoroughly cleaned every 10 to 14 days even in the absence of a unique event like what seems to be going on this year.
There are avian diseases that commonly are spread at bird feeders, especially in the warmer months. Things like trichomonas, which is a protozoan parasite, and you've got others like avian pox that may be spread there, salmonella may be spread there and is a pretty big killer of small birds. And then mycoplasma is a bacteria that can lead to similar symptoms to what we're seeing here. It's primarily known in house finches.
So regardless of whether or not this is viral, or what the origin of it is, it's still solid guidance for people to do their part for the resource that they care about and are feeding to try to keep them healthy.