Feathers And Snarge: Identifying What’s Left After Birds And Planes Collide

11:37 minutes

Carla Dove (right) and her team at the Smithsonian Institution’s Feather Identification Lab. Credit: Chip Clark, Smithsonian

Collisions between birds and airplanes can result in a range of damage, the most severe being the kind that brought down US Airways Flight 1549 into the Hudson River in 2009. A flock of Canada geese snuffed out both engines on that plane shortly after takeoff. To prevent future bird-related calamities, airlines need to know which species are most likely to get entangled with aircraft in the first place.

That’s where forensic ornithologist Carla Dove, of the Smithsonian Institution’s Feather Identification Lab, comes in. From April through June 2016, she received the remains of more than 2,000 birds that had been struck by airplanes, whether or not the plane had suffered damage. The Federal Aviation Administration and the military had sent them, wanting to know, in each case, the species. Black vulture? Canada goose? Horned lark? (The horned lark, by the way, is the most common collision casualty, not the Canada goose, as some might think.)

Carla Dove, of the Smithsonian Institution’s Feather Identification Lab. Credit: Chip Clark, Smithsonian

In the research wings of the Smithsonian National Museum of Natural History in Washington, D.C., Dove and her crack team of scientists solve more than a dozen of these avian mysteries every day. Sometimes they work with remains consisting of as little as a single brown feather, other times they must sift through a gruesome mix of plumes and innards known as “snarge.” Their detective work also relies on the Smithsonian’s vast array of more than 600,000 preserved bird specimens and, more recently, DNA processing.

[These photographs of birds’ dazzling plumage take center stage at the Royal Ontario Museum.]

Dove explains the CSI-like nature of her work, and how the data from these gory post-mortems can lead to saving birds’ lives in the long run.

Segment Guests

Carla Dove

Carla Dove is a forensic ornithologist. She’s Program Manager of the Feather Identification Lab at the Smithsonian Institution in Washington, D.C..

Segment Transcript

IRA FLATOW: This is science Friday. I’m Ira Flatow. It’s spring in the Northern Hemisphere. And you know what that means? The robins are back, the geese, and all the other birds are migrating back from their winter feeding grounds.

But along the way, as many as 2,400 of them, could meet an untimely end by hitting airplanes this year. That’s how many bodies my next guest received between April and June in her lab last year. Yes, Carla Dove collects bodies of birds. Well, she actually collects the remains. Sometimes they’re just the feather fragments and smash tissue. The technical term is snarge.

And that’s right– my next guest deals with the casualties of bird plane collisions, trying to identify what species they once were, because airlines the military and others want to know what species are most likely to fly in front of a plane. Maybe we can use that knowledge to prevent those species from hanging out near airports, or at least build aircraft that can withstand those collisions. Behind the scenes of all this is Carla Dove, a forensic ornithologist and program manager of the Feather Identification Lab at the Smithsonian here in Washington. Welcome to Science Friday.

CARLA DOVE: Thank you so much for having me.

IRA FLATOW: Before everybody does it, let me ask you about–

CARLA DOVE: Yes, that’s my name.

IRA FLATOW: Working with birds, do you have a no special love for the dove or the pigeon or that family.

CARLA DOVE: Well, actually the only time that ever became a specific problem was when I was trying to decide on what project to work on for my PhD thesis. And my advisors said, whatever you do, you cannot select the family Columbidae, doves and pigeons. You’ll never live it down.

IRA FLATOW: But Dr. Dove fits right in.

CARLA DOVE: Yeah, that’s the way they remember my name. So, whatever works.

IRA FLATOW: That’s what I say. Is your work anything like CSI ornithology? I mean you collect– How did you come up with that name? What is it? The–

CARLA DOVE: The snarge?

IRA FLATOW: The snarge.

CARLA DOVE: Yeah, snarge is a term that we have always used at the museum in the prep lab where we skin birds. And we have a lot of bird ick laying on the table. And so when we started working on birdstrike identifications, that was sort of a natural word to use, and for that case, it’s bird ick. So snarge came from the prep lab at the Smithsonian. But we sort of claimed it as our term now.

IRA FLATOW: So it’s forensic. What does that mean?

CARLA DOVE: It is, in a way. I mean, it’s not technically forensic because we don’t do law enforcement cases. But we do use forensic techniques. And so we look at the trace evidence. We look at the microscopic characters, the DNA, the circumstantial evidence to solve our puzzle, which is ultimately the identification of a species of bird.

IRA FLATOW: So if you’re going to identify them, then you must keep samples of birds to match with.


IRA FLATOW: How many birds are in your collection?

CARLA DOVE: Well, actually we are located right upstairs in the National Museum of Natural History at the Smithsonian in the bird division. And the bird division was founded way before there were ever airplanes flying. So, we are just a user of that huge collection there. But that is our resource and our research collection. So, we have somewhere around 620,000 museum specimens up there in the drawers. We represent about 85% of the diversity of birds of the world. And so it is an ideal place to conduct this kind of research.

IRA FLATOW: So how many birds actually get hit by planes or vice versa.

CARLA DOVE: That’s right. The birds aren’t actually flying into the planes. It’s not their fault. But we, every year, our lab identifies over 9,000 cases. And you mentioned at the beginning of the show that we do about 2,400 in spring migration. But totally, for the year, it’s over 9,000 samples that we receive. Now we don’t receive all of the samples. So there are somewhere around 13,000 bird strikes reported to civil aviation and another 4,000 to 5,000 from the military. So it’s quite a quite a few birds every year.

IRA FLATOW: So who picks up these samples? How does a sample get to you?

CARLA DOVE: It’s taken some time. But we’ve got people trained in the field now. The military has a bird aircraft strike hazard team that will pick up the remains. The civil aviation have biologists on the airports that pick up remains and send them to us.

IRA FLATOW: And so how often do you have a completely unsolved mystery? A lot of times?

CARLA DOVE: No, not really. We have great tools to do the works. And we have DNA, and we have microscope analysis. And we also use whole feathers. And so about 98% of the time we get it to some level. We say it’s a duck, but we can’t say it’s a Mallard or Pintail. And a few times, if it’s just a piece of black feather with no characters or no pattern or no microscopic diagnostic characters, then we just have to say it’s a bird.

IRA FLATOW: How small a piece of feather do you need? What part?

CARLA DOVE: Sometimes we can do it with a single– just a single barb from the fluffy part of the feather. And that’s the base of the feather, the part of the feather that is responsible for insulation and keeping the bird warm. That’s where the real diagnostic characters are located. So we need that part, but we don’t need very much.

IRA FLATOW: If somebody sends you some snarge, let’s say, and you analyze it. Do you ever say, hey, this isn’t a bird. Somebody sent me something. What is it?

CARLA DOVE: Well, if we get that, somebody is going to get an earful because we are very serious about what we do. We don’t want people sending us jokes. But we do get things that are interesting that are valid.

IRA FLATOW: Tell me.

CARLA DOVE: Like fish and–


CARLA DOVE: Yeah. And deer and–

IRA FLATOW: Wait a minute, backup. How does a deer get on a plane? I don’t say they buy a ticket.

CARLA DOVE: We do get snakes, too.


CARLA DOVE: Well, the interesting thing is– and it all turns out to be pretty much the same story– is it’s usually a bird was either feeding on that animal, or the bird was carrying it in its talons. And it just– when it hits the plane, everything goes everywhere. And that’s the part of the sample that we receive. And so–

IRA FLATOW: Interesting. I know that your team worked on the aftermath of that crash that led to the so-called Miracle on the Hudson and a plane that landed in the river. Was it any mystery that the plane had hit geese, no? I mean– Well

CARLA DOVE: That’s a good question, because they did– the pilot, I think, reported geese. And they did think that’s what it was right, initially, in the very beginning of the investigation. We had to confirm that for several reasons. One reason is that there is another bird that looks very similar to a Canada goose in New York called a Brant. And that bird weighs significantly less. It’s a three to four pound bird. And the engines on that aircraft were designed to take a three to four pound bird and keep on functioning.

And so the engineers were very concerned, in that case, about what the exact species of bird was to get the weight the average weight on that. And so when we decided and determined it was Canada Goose, they were relieved to know that an eight pound bird, a ten pound bird is not supposed to go through their engines and the engine not supposed to keep on working. So, that was part of it. And then we want to know the exact species. So, as you said in the beginning of the program, so that we can know what that bird eats and why is it there and when is it there and what potential problems could it cause. And then you can go out on to the airfield and do something to–

IRA FLATOW: What do you do, if you know there’s a bird hazard, what can you do at an airport?

CARLA DOVE: There’s a lot of things that you can do. There are Border Collies that keep certain birds away. There are Peregrine Falcons or other falcons that can be trained. Sometimes it’s as simple as cutting the grass.

IRA FLATOW: So you take away their nesting.

CARLA DOVE: You take away– if they wanted to have a flat airy area where they can go and look around and see predators coming their way, let the grass grow a little bit, and they not feel comfortable there anymore.

IRA FLATOW: Oh, just the opposite.

CARLA DOVE: Yeah, but, on the other hand, if you know there’s tall grass, and there’s lots of little mice and different kinds of rodents burrowing around in there, and the hawks are going to come to hunt and feed there. So, you have to know the problem on a specific airfield. And that’s where the species identification comes in.

IRA FLATOW: I know you’ve been doing this for 25 years. Have you noticed a change at all in the patterns of bird strikes or anything over time?

CARLA DOVE: Yes, we have. And that’s also another interesting question, because now we’re seeing things– some distributions of birds are changing. And, for example, the black vulture used to be a bird that was always in the South and never really got that far north. And now, more and more, we are seeing those in bird strikes from northern states. And so over time, bird distributions change. We don’t know why or what’s the cause of it. But we can just see those kinds of things in our data.

IRA FLATOW: Does anybody– they know that you’re a forensic ornithologist. You deal with birds. Does anybody ever send you stuff that may have a bird in it, wants an identification of what– you know, maybe it’s an animal has swallowed it, or something like that.

CARLA DOVE: Yes. We worked on a project. In fact, we’re still involved in it with Everglades National Park biologists on identifying the prey remains of the Burmese Python. And so the Pythons are wreaking havoc down there. There are non-native species, and they’re eating birds. And, of course, once you get the stomach contents of a Burmese Python, it’s not going to be the most pleasant thing you want to see in the morning.

IRA FLATOW: I’ll bet.

CARLA DOVE: But the snake DNA will overtake the sample. And so it’s very difficult to get DNA from material like that. So we’re using the morphological characters of the bones and the feathers and the microscopic characters of the feathers to help us determine the species that they’re eating.

IRA FLATOW: See if I get a quick call in from Dillon in California. Hi welcome. Go ahead.

CALLER DILLON: Hey. Good morning. I’m in the Air Force. And so I’ve actually sent some samples to Carla as part of the safety team. So first of all, I just want to say thank you for your work.

CARLA DOVE: Thank you.

CALLER DILLON: So my question was with the samples that we sent in were international. And I was wondering how long those take to get to you guys, and if they have any smells or anything weird by the time they get to you.

IRA FLATOW: Thank you.

CARLA DOVE: Almost all of them have some kind of smell.

IRA FLATOW: Customs– they have to go through customs?

CARLA DOVE: They have to go through customs. And we have to have all kinds of special permits to allow them to export and us to import. And they have to be treated, so that we’re not importing diseases or different kinds of viruses. So all of that procedure has been worked out. But it does take a little bit longer for us to get samples from overseas. And we do realize that the Air Force has a 30 day turnaround time. So we do try to put those up to the head of the line.

IRA FLATOW: Do you get a call from an airport, let’s say like JFK, which has a lot of stuff, and says we don’t know what this is. But it may be heading– it may be for you because we’ve sent other bird stuff to you.

CARLA DOVE: Yes, we do. They definitely give us a heads up, especially if they’re sending something priority that has caused damage or something that they would really like to know about. JFK is very good about reporting bird strikes.

IRA FLATOW: They certainly live in the neighborhood. There’s a sanctuary there. Thank you, Dr. Dove.

CARLA DOVE: Thank you.

IRA FLATOW: Dr. Carla Dove, Program Manager of the Feather Identification Lab. I’ll bet you never knew they had one until today at the Smithsonian Institution here in Washington.

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