Bringing Back An Endangered Crow

12:28 minutes

The ʻAlalā a nearly extinct species of Hawaiian crow. Credit: San Diego Zoo Global

About five million years ago, the island of Kauai emerged from the ocean waves, and a new chain of island habitats was born, right in the middle of the Pacific. In those Hawaiian islands, birds would have found a multitude of microclimates, a lack of most predators, and a pretty safe spot to grow and evolve—which they did, diversifying into a wide range of species, each suited to a different lifestyle and habitat.

[A daily audio diary of the narwhal.]

But today Hawaii’s diverse birds are under attack by invasive mongooses, cats, rats and other predators. Some birds no longer breed in the wild and need the help of humans to reproduce and survive. Alison Greggor, a post-doctoral research associate at the San Diego Zoo’s Institute for Conservation Research, joins Ira to talk about efforts to rehabilitate the nearly extinct Hawaiian crow, the ʻAlalā, and the race to save delicate bird eggs before predators get them first.

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Segment Guests

Alison Greggor

Alison Greggor is a post-doctoral research associate at San Diego Zoo’s Institute for Conservation Research.


Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow, coming to you from the Kahilu Theater in Waimea, Hawaii.


About 5 million years ago, the island of Hawaii emerged from the ocean waves. And a new chain of island habitats was born right in the middle of the Pacific. Here in the islands, the birds would have found a multitude of microclimates, a lack of most predators, and a pretty safe spot to grow and evolve, which they did, diversifying into a wide range of species, variations on a theme each suited to a different lifestyle and habitat.

But today, Hawaii’s diverse birds are under attack by mongooses, cats, rats, other predators. Some birds no longer breed in the wild and need the help of humans to reproduce and survive. Alison Greggor is one of those avian helpers and a postdoctoral research associate at the San Diego Zoo’s Institute for Conservation Research in Volcano. Welcome to Science Friday, Dr. Greggor.

ALISON GREGGOR: Thank you. It’s a pleasure to be here.


IRA FLATOW: Now, one of the species that you study is a type of Hawaiian crow. It has an unusual name. What do you call it?

ALISON GREGGOR: So the Hawaiian crow is the alala. And it’s a name that historically actually meant “caller of the forest.” And so it carries a lot of cultural significance as well, not just a throwaway name. They’re a very important species.

IRA FLATOW: Give us a bit of the life story of the bird.

ALISON GREGGOR: So as part of the corvid family, the Hawaiian crow is known to be one of the more intelligent birds of the Hawaiian Islands. It does mean that they have a life history that’s a little bit slower than some birds. It takes them several years before they become of reproductive age.

And historically, once they became adults, they would actually form territorial pairs. And you would find them across different areas in the landscape, but mostly in the wet tropical forests. They unfortunately were in serious decline by the 1950s due to a number of different factors, which you explained. But they became extinct in the wild in 2002 due to all of those factors.

Fortunately, before that time, the program that I worked with, the Hawaiian Endangered Bird Program, actually brought individuals into captivity and started a conservation breeding program. And that is why they are still alive today.

IRA FLATOW: Where did you raise them?

ALISON GREGGOR: So we have two facilities, one on this island, the Keauhou Bird Conservation Center, and then one on Maui. Every time you breed a new species, it’s a real challenge. The process of hand-raising birds and making sure you have an environment that most closely represents the wild environment to make them want to breed and make sure that they are comfortable as well is actually– it’s an iterative process that we’ve learned over the years how to make that more successful.

But the problem with any captive reared animal is that, as you well know, the captive environment doesn’t mirror the wild. It’s missing key elements of what birds need to be able to do in the wild, like find food and avoid predators and even navigate a wide space.

IRA FLATOW: Do you need a minimum number of birds to start off with to make it successful?

ALISON GREGGOR: So the larger number you start with, the better, as one might expect. With the alala, we started with nine genetic founders, which is quite small. Ideally, you would have more like 30 or 40. It would be optimal to have 50.

IRA FLATOW: So I would imagine that there would be a danger that you don’t have enough genetic diversity with just nine birds.

ALISON GREGGOR: Yes, especially when you’re dealing with an island species. Island species tend to go through a genetic bottleneck when they arrive on an island. And so for them, they may be particularly more vulnerable to some of those inbreeding effects. But we’re fortunate to have collaborators who are working on the genetics of the alala to help us better understand how to optimize the genetic variability that we do still have.

IRA FLATOW: Now, what happens if you get two really rare birds that you want to breed, but– how shall I put this gently for our family audience– they don’t want to do it?

ALISON GREGGOR: Yeah. So that’s actually part of the research that I’ve been doing while within the Center is to better understand how mates choose each other. What are they looking for? Are there certain personality traits that make pairs more compatible or not? Because it is actually true.

IRA FLATOW: They do have personality.

ALISON GREGGOR: Yes, they do. Yes, they do. And not only can you see it when you just observe them. But actually, you can quantify it as well. You can give them personality tests the way that we would think of giving person a personality test. And so we’re still learning a lot about what makes pair compatibility. Is it that opposites attract?

IRA FLATOW: Do you have any techniques for enhancing the romance, chocolate and that sort of thing?

ALISON GREGGOR: At this stage, since we know there used to be territorial, giving them space.


ALISON GREGGOR: Yep. So our aviaries are optimally designed to allow a breeding pair to have its own aviary so that they can basically have some privacy from their neighbors.

IRA FLATOW: And so once you’ve started, you get a population going, how do you know it’s been a success, that things are working out well? Do you track them to see where they go with things like that?

ALISON GREGGOR: So when we release them, we actually fit them with radio tracking backpacks. So they have a little receiver on their back. As they fly around in the forest, we can keep track of them. Otherwise it would be near impossible to find a bird in a big forest.

IRA FLATOW: All right. We have some questions in the audience. Yes, sir.

AUDIENCE: You had a release that was unsuccessful where you had several birds that were preyed on. Could you tell me how that happened and how that is going to be looked at in the future?

ALISON GREGGOR: Sure. So any release program that is starting up– there’s a lot to learn. There’s many steps that both the program directors and the birds themselves have to go through to get to that process. In 2016, we released five individuals. And within a week, unfortunately two of them had been predated by ‘io, the native Hawaiian hawk. And one of them dispersed and was found in poor condition at that point and had passed away.

Since that time, we sat down with our many conservation partners. And we developed a new plan. We increased the rigor of the anti-predator training. And we also released a larger group of birds. So there are more eyes in the sky looking for the predators. I’m happy to say that since that time, we have released 11 individuals. And they are all still flying free.


IRA FLATOW: So when you say “anti-predator training,” you had to teach them how to avoid being eaten?


IRA FLATOW: How does that work?

ALISON GREGGOR: So we actually create what would be a little play next to the aviaries. Naturally, birds would learn socially what are the predators to fear because if they had direct experience with a predator, they wouldn’t survive. So they would learn from both their peers and their parents what was a predator.

And they actually have a very distinct alarm call, which basically says, danger, danger, watch out. And if they ever witnessed a predation event, birds actually then have a distress call saying, ouch, ouch. I’m hurt.

So what we did with the help of the local Panaewa Zoo near here– they let us borrow an ‘io that they have. And we actually staged this natural learning event for the birds. So we played alarm calls and distress calls and showed them a flapping ‘io and then actually put a taxidermy crow under the ‘io’s feet. And it worked.

IRA FLATOW: You know, I got to say that I am not surprised by this, because we always hear news stories about how smart crows are. They’re very smart birds, aren’t they?


IRA FLATOW: They’re toolmakers. They do all kinds of things.

ALISON GREGGOR: Yes, yes. And we know they continue to learn throughout their lifetime. A lot of animals learn only in a very sensitive period when they’re young. But they are able to pick up new things throughout their lives.

It’s wonderful that they can hopefully learn a lot more when they go out. But it means the training process has to be a lot more rigorous because there’s a lot more that they don’t have innate they need to learn.

IRA FLATOW: That’s interesting. We’ll take one more here, then we’ll go over here. Yes.

AUDIENCE: You said you started with nine birds. How many are there now?

ALISON GREGGOR: So we have about 125 right now.


IRA FLATOW: You know each one of them?

ALISON GREGGOR: Actually, I do. Yeah.

IRA FLATOW: I would. I would.

ALISON GREGGOR: So all of our birds have Hawaiian names.

IRA FLATOW: Name all of them right now. It’s OK.

ALISON GREGGOR: I don’t know if the radio show is long enough for that one. But yes, because we’ve been trying to learn and understand as much as we can about these birds, we’ve run personality tests on all of them. And the staff at our breeding facilities have been working with these birds for years and years. And we know a lot about each one of them.

IRA FLATOW: What is the lifespan of a crow like this?

ALISON GREGGOR: So we don’t yet know how far they can actually go, because in captivity they often live a lot longer than they would in the wild previously. But we have birds that are 27 years old. But we don’t know how long they used to live in the wild.

IRA FLATOW: Wow. We’re in our 27th year at Science Friday. So there must have been a bird that– happy to find that bird. This kind of rescue and the kinds of things that you’re doing– has that happened in many different places? Or is it sort of unique here?

ALISON GREGGOR: It’s a growing field. The first real attempt in the United States was the California condor, which was done by the San Diego Zoo. And they had a similar story. They actually were extinct in the wild at one point, and now there are over 350 birds flying. And that has been 20 years of very intensive efforts to bring them back.

And so we do have models. On this island, many people may know the nene. This is the Hawaiian goose. They were never extinct in the wild, but their populations dwindled. And they now number in the thousands.

IRA FLATOW: Wow, fascinating. Thank you, Dr. Greggor, for taking time to be with us today. Alison Greggor is postdoctoral research associate at the San Diego Zoo’s Institute for Conservation Research in Volcano. Thanks again.


After the break, why Hawaii is ground zero for an extinction crisis and how ecologists are outsmarting invasive species. Taking us to the break, our musical guest for the evening, Makana.



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