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We end our season with a little seabird that’s making a comeback. The Hawaiian Petrel, or ‘Ua’u, was once written off as going or gone from the islands. But after recent discoveries of remnant colonies, we see how some human intervention with the right tools can make a huge difference for birds and protect a population on the brink.
Brief explicit language at 6:22
Ari Daniel: BirdNote Presents.
[Echoing Wingflaps SFX]
[Reflective Threatened theme music begins]
Ari Daniel: I’m Ari Daniel and this is Threatened. This is our last episode in Hawai’i, where we’ve been examining the immense challenges that the birds here face and the people dedicated to making the islands safe for them again. Today we’re looking at Hawaii’s seabirds – specifically the Hawaiian petrel or ‘u’au… a name that mimics its call.
[Many ‘Ua‘u in the Lānaʻi colony calling raucously]
‘Ua‘u are endangered— there are fewer than 18,000 remaining — and their behaviors make them difficult to detect, let alone protect. Historically, ‘Ua‘u used to breed at all elevations. But these days, due to impacts from coastal development and introduced predators, they nest in some of the most extreme places on the Hawaiian islands. We’re joining reporter Jessie Eden as she visits three remote outposts of nesting ‘Ua‘u in the Hawaiian Islands – to find out how these little birds can cope, even thrive, in each place… once we know they’re there.
Jessie Eden: We’re starting in Hawaii Volcanoes National Park… on Mauna Loa, the second tallest mountain in the islands. I wanted to go here because for decades biologists have put in some serious work even to just find the birds that live here. And once they do that, they can advocate for measures to protect them.
Ari Daniel: Wait a minute, Mauna Loa is an active volcano on the Big Island, right? So, tell me, what's it like to be up there?
Jessie Eden: Well, on Mauna Loa there's this wonderful mosaic of old lava flows from the past centuries throughout the upper elevations.
The ‘Ua‘u nest in small lava tubes and cracks and crevices up there.
Ari Daniel: So basically these tubes, you get flow of lava and then as lava cools, it pulls away and creates kind of a cavity?
Jessie Eden: Exactly. These holes, called pukas in Hawaiian, are perfectly snug places to nest in. The Mauna Loa petrels nest at elevations of 8 to 9,000 feet on the mountain. That's higher than Machu Picchu in the Andes of Peru. But unlike Machu Picchu, there are no roads leading there. The only way into this core nesting area is by helicopter. So wildlife biologists who study the ‘Ua‘u are flown up there. Then, they set up camp for several days.
Charlotte Forbes Perry: The temperatures can go below freezing and you wake up with ice on your tent.
Jessie Eden: Charlotte Forbes Perry is a wildlife biologist with the Pacific Cooperative Studies Unit and Volcanoes National Park. Charlotte has taken helicopter rides to these upper reaches of Mauna Loa countless times.
[Tranquil ambient music music begins]
Charlotte Forbes Perry: But once we get here, I'm really happy to be here. It's so quiet. Sometimes, I swear we could hear our blood moving in our bodies.
At night, if it's a clear night, you can see down to the Kilauea crater. The stars are pretty darn amazing. You're just this little speck on these big open flows.
Jessie Eden: On nights when Charlotte is gazing at the stars, ‘Ua‘u are on the move— they’re busy flying to and from the ocean in darkness. In fact, ‘Ua‘u behavior is so mysterious that Charlotte has only seen a handful of ‘Ua‘u up-close… even after studying them for the past 14 years.
Waking up with ice on her tent for birds she almost never gets to see, this seems like a job with a lot of cost and not a lot of obvious reward. But Charlotte grew up here in the islands, and it’s more than just a job for her.
Charlotte Forbes Perry: I think that my role in trying to take care of these birds, these ‘Ua‘u, is my contribution to my cultural upbringing. We believe these birds are our ancestors or, you know, family members. And we should do what we can to keep them as healthy as possible.
[Tranquil music fades out]
Jessie Eden: This particular ‘Ua‘u colony here on Mauna Loa is fairly sparse. Currently, there are only about 80 known active petrel burrows that Charlotte regularly monitors. Monitoring these nest burrows helps us understand what’s going on with the ‘Ua‘u population. Much of their life is spent on the open ocean, so during the breeding season, when they’re on land, is when we really get to study them.
Since ‘Ua‘u behavior on the mountain is so cryptic, motion-sensing cameras are vital to understand what’s happening. Charlotte is setting one up outside a burrow.
Jessie Eden: All right. So you're getting the batteries in there.
Charlotte Forbes Perry: Yeah.
Jessie Eden: And this is one of those, those nests that you sort of found off the cuff, right? Just cruising on by?
Charlotte Forbes Perry: Yeah. Just saw a bunch of poop and looked around and took us a couple tries and found the actual hole.
Jessie Eden: The wildlife cameras that biologists use in the petrel colonies capture delightful images of the ‘Ua‘u — you know, adults waddling to and from their burrows. And then later in the season, the chubby chicks all covered in their fluffy down feathers.. but then there are also some difficult images to watch.
Charlotte Forbes Perry: So this is nest 226. We're watching a, um, adult cat. You can see it's kind of a right around the corner and it's pushing on something and…
Jessie Eden: [Gasps] Oh my God.
Charlotte Forbes Perry: And it has, it's coming out with… a dead ‘Ua‘u .
Jessie Eden: Oh my goodness.
Charlotte Forbes Perry: Yeah.
Jessie Eden: Uh, at 9,000 feet, that is horrifying.
Charlotte Forbes Perry: Yeah.
Jessie Eden: What happens for you when you see that? You're expecting to see a bird…
Charlotte Forbes Perry: Oh, I'm, I'm kind of talking really loud to myself, in the office by myself going, “holy shit. Fuck. Unggg!” It's hard to watch. It's very hard to watch. Yeah. There's just no good way to get rid of them except for the fence at this point.
Jessie Eden: In 2016, Hawaii Volcanoes National Park did complete a cat proof fence around a section of the Mauna Loa colony. They did this because of the work of Charlotte and her colleagues, who were able to show evidence of the burrows there. So they keep at it, searching and monitoring burrows to make clear the need for more fencing and protection for the other ‘Ua‘u .
Charlotte Forbes Perry: We look for signs of activity when we're walking around out there on the lava. And one of the main things that we're looking for is ‘Ua‘u poop. So when we see that on the lava, we look around that area for more, like feathers. And then we'll look for the burrow opening, which could be a little cryptic at times, but then we also smell inside the area. Those are the main signs that we're looking for when we are looking for an active nest.
[Recording of Mauna Loa ‘Ua‘u Colony; several ‘Ua‘u calling]
Jessie Eden: Charlotte keeps her eyes and nose out for monitoring this relatively small colony… and I got to help her out with her work.
[Mischievous music begins]
Jessie Eden: Okay. So which burrow is this one?
Charlotte Forbes Perry: Uh, this is nest, uh, 134.
Jessie Eden: And it is big enough for us to crawl in — or I guess I should say, me?
Charlotte Forbes Perry: Yeah, you… ‘cause it's that way.
Jessie Eden: It's this way.
Charlotte Forbes Perry: It's yeah, and it gets a little tight.
Jessie Eden: Yep. It looks a little tight, but lots of good poop.
Charlotte Forbes Perry: Yeah. And definitely looks active at this time. Yeah. And then you look to your right.
There's a possibility of seeing the, the adult at this point.
Jessie Eden: Get the flashlight handy. Sounds good. And you'll pull me out, yeah? If I get stuck?
Charlotte Forbes Perry: Yes.
Jessie Eden: Okay, good.
Ari Daniel: I commend you, Jessie, for getting in there. It sounds pretty tight. Did you get claustrophobic?
Jessie Eden: [Laughs] Well, I'm not typically claustrophobic, but these lava flows can be pretty jagged.
And so it catches on your clothing and stuff. And so sometimes, as you're trying to move forward or backward, you're kind of getting stuck in there. It's nothing serious though — I was able to maneuver my body and just squish in there.
[Mischievous music rises for solo, then fades]
Ari Daniel: So what did you see??
Jessie Eden: I didn't get to see a petrel, but the signs of activity were unmistakable — you know, poop outside the burrow, that strong musty marine smell inside.
Ari Daniel: Ok, so if the birds aren't at the nesting site, then where are they?
Jessie Eden: So ‘Ua‘u move back and forth, mauka to makai — from evening to the early mornings. Remember, they’re flying to and from the mountain in darkness.
Ari Daniel: Sorry, did you say Mauka to makai?
Jessie Eden: Yeah. So, mauka - toward the mountain, makai - toward the ocean. And so they're out foraging, out on the open ocean, when they're not on the mountain.
When their single chick has hatched, the parents take turns heading back out to the ocean to feed on squid and other seafood.
Pairs work diligently, alternating their foraging trips and staying on the mountain with the chick. And sometimes their foraging takes them as far as the Aleutian islands.
Ari Daniel: Wow! Up in Alaska?
Jessie Eden: Yeah! Those were birds that were tracked from Kauai. Now I think it's believed that the ones here on Mauna Loa go as far as the waters off of Washington State. Still pretty darn far. Of course they don't always go that distance, often they’ll forage out to a few hundred miles offshore – but they’ve discovered that ‘Ua‘u occasionally make these enormous trips. Research with satellite transmitters tells us that sometimes they travel over 7,000 miles, the equivalent of traveling from, say, Seattle to Patagonia in South America.
Ari Daniel: 7000 miles! That's incredible, Jessie. So for a petrel to go from Hawaii up to Alaska in search of food, how long would that take them?
Jessie Eden: Oh, that's a couple of weeks.
Ari Daniel: Oh man, so these birds are doing these weeks-long, epic journeys to Alaska or Washington, and then they finally get home… just to become dinner for a cat, huh?
Jessie Eden: Yeah, it’s just especially heartbreaking to see that happen after all that hard work. So Charlotte is working on getting more predator proof fencing — but for now, she’s grateful for the fence that she already has.
[Quietly bittersweet music begins]
Charlotte Forbes Perry: Those cats can do so much damage. It's so nice monitoring, just knowing you're not going to find carcasses of, um, ‘Ua‘u while you're doing the monitoring, because the fence has been working well and keeping the cats out.
[‘Ua‘u calls from the Lānaʻi colony]
Ari Daniel: We’re going to take a break, and when we come back, finally some good news, Jessie takes us to a very different environment where the ‘Ua‘u are thriving.
[Bittersweet music fades out]
[MIDROLL AD BREAK]
Jessie Eden: Unlike the modest ‘Ua‘u colony on Mauna Loa, some of the other petrel colonies in the islands are remarkably robust.
[Lānaʻi ‘Ua‘u calls; it sounds raucous, with many birds calling]
Ari Daniel: Well, what do we have there? That sounds fun.
Jessie Eden: This is the ‘Ua‘u colony on the little island of Lānaʻi. Can you believe that for 100 years we thought there were hardly any ‘Ua‘u here? There are so many.
Ari Daniel: Wow! I mean it sounds so different from where we started on the top of that volcano.
Jessie Eden: Oh yeah, just a radically different environment from stark open lava flows at eight, 9,000 feet. Compared to Hawaii Island, Lānaʻi is a tiny, relatively low-lying island. Its lush highland ridges reach to just over 3,000 feet.
[‘Ua‘u calls fade out]
Jessie Eden: Often when people think of Lānaʻi, they think of pineapples – large-scale agriculture dominated this landscape for many decades.
And because so much extractive land use has happened here, folks didn’t really consider what a biological gem it could be.
Rachel Sprague: Lānaʻi is unique in that it's only got about 3% of its original native forest left —
Jessie Eden: Biologist Rachel Sprague is a co-director of conservation for Pulama Lānaʻi.
Rachel Sprague: But what's in that forest is still some of the highest density of nesting ‘Ua‘u anywhere in the main Hawaiian islands. If there's uluhe ferns, there's petrels nesting in it still.
Jessie Eden: ‘Ua‘u here nest in tangles of green uluhe ferns. This chest-high thicket of these viney ferns undulates along the steep Lānaʻi highlands. Having dug their burrows deep within these nearly impenetrable interwoven braids of green, nesting ‘Ua‘u here are just as enigmatic as anywhere else. In fact, for nearly a century the ‘Ua‘u colony here was 'written off' as barely there, nothing significant. In the early 1900’s, there was a naturalist who wrote about them.
Rachel Sprague: And he said, well, there's maybe 50 to a hundred. In the 70’s, someone was doing surveys for native birds. And again said, we found a few dozen to a few hundred, but the colony probably seems to be pretty close to extinct. In the 1980s, referenced that study from the 70’s, and said they still had found some birds likely nesting on Lānaʻi, but they've got to be probably extirpated by now.
Jessie Eden: But now there are actually estimated to be about 4,000 pairs of ‘Ua‘u on Lānaʻi! The island has very little development and just a few urban lights, so the darkness is perfect for these night-flying birds – in more urban settings, they can often become disoriented by bright lights and crash into power lines and other structures. Thankfully that’s not an issue here.
[Bittersweet slightly tense marimba and vibraphone music begins]
But they do still face challenges. Rachel arrived on island in 2016 to begin ‘Ua‘u studies here.
Rachel Sprague: At the end of that season, we found about 20% of the nests had succeeded.
Jessie Eden: Four out of five of the nests monitored that year had failed. Either the adults, the eggs or the fluffy petrel chicks were eaten—
Rachel Sprague: largely due to cats and rats. That was a big wake up call. And so we expanded cat control. We expanded rodent control.
Jessie Eden: So they started trapping and killing the invasive predators. A difficult but necessary measure.
[Recording of Lānaʻi Colony; Many raucous ‘Ua‘u calls]
[Music is slightly more hopeful sounding now]
Rachel Sprague: And just the next year, we had over 70% nesting success. Now, five years later, it's sitting at about 80% nesting success — just with predator control.
Jessie Eden: But trapping alone won’t cut it. Ultimately, what they need in this colony is a fence, like on Mauna Loa. Money is typically the hesitation with fences – it's an expensive endeavor – but the team on Lānaʻi is moving ahead. The predator proof fence is under construction.
When we deal with the introduced predators that attack these birds, the birds bounce back.
But we can only protect the petrels if we know where they are…
[Music and ‘Ua‘u calls fade out]
In addition to Mauna Loa, Lānaʻi and a few other places, another high elevation Hawaiian location was known for petrels.. until it wasn’t. That’s Mauna Kea, the tallest mountain in the islands…it’s here on the Big Island. Much of Mauna Kea’s landscape has been completely changed over the past couple hundred years with the introduction of cows and pigs and sheep and cats and rats and mongoose… I could go on. So biologists believed petrels had been totally eliminated from Mauna Kea since 1954.
But with rediscoveries of seabirds in other areas of the state, biologists started to think that, maybe, ‘Ua‘u could still be on Mauna Kea, somewhere. In 2017, they began to search for them..
[Mimicked ‘Ua‘u calls]
Ari Daniel: That sounds a little different than what we heard before. Is that an ‘Ua‘u?
Jessie Eden: No – but it’s one of the biologists who was part of this search.
Bret Mossman is a wildlife biologist with Hawaii’s Department of Land and Natural Resources. Remember how Charlotte used sight and smell to detect ‘Ua‘u ? Well, in this circumstance, Bret and his crew started their ‘Ua‘u searches by using just sound. They deployed songmeters around Mauna Kea’s upper reaches.
Bret Mossman: We had lab staff, interns, volunteers, we're all working on this, you know? And so it took hundreds and hundreds of hours from dozens of people
Jessie Eden: The songmeters record sound on the mountain. At various intervals through the season, the researchers retrieve their SD cards and analyze the recorded sounds. But some of the sounds from Mauna Kea’s upper elevations, Bret and the team experienced in person.
Bret Mossman: Yeah, so one of the first things that we found, um, when we were looking for ‘Ua‘u here was, we heard this like, really, like strange, almost laughter.
[Breathy laughter echoes around the background]
It’s like the best way that I can describe it, but it's like this breathy laugh. And it's in the middle of nowhere at like one o'clock in the morning on Mauna Kea. and it’s like, oh boy –
[Breathy laughter continues]
It was like one of those chicken skin moments for sure.
Jessie Eden: A year passed. And then, one day, Bret was out working on the south side of Mauna Kea… some of the team was on the mountain with him and some were in the office analyzing recordings…
Bret Mossman: We were clear up at about 12,000 feet deploying songmeters. And my coworker at the time called me and was like, we got ‘em.
[Optimistic pizzicato string quartet music begins]
And, and I was like, oh my God. It was, like, unbelievable. And you're at high elevation — so you're already a little loopy. And I was like, I was so ecstatic to learn that we finally heard them, you know. So they, like, played the sound over the phone for me to hear, and it was just like, it was incredible.
[Lone ‘Ua‘u from Mauna Kea, with telephone effect]
Jessie Eden: The confirmation of this first ‘Ua‘u call was in 2018, and Bret’s work only ramped up; now, they were looking for burrows… like I did with Charlotte on Mauna Loa.
While I help him set up some rat traps, Bret tells me about tracking one ‘Ua‘u.
Bret Mossman: We went over and we were searching, searching. Couldn't find the burrow, couldn't find the burrow. And so I was kind of like starting to lose hope and I was like, dang it, we can't find it.
Jessie Eden: As he was looking around, he saw a beautiful purple-blue flower.
Bret Mossman: And then I was like, oh, there's an ‘ōpelu– it’s one of our beautiful, lobeliad flowers that are so famous here in Hawaii for their adaptive radiation. First time I'd ever seen one in bloom. And I was like, oh, that's so cool. So I walked down to where it was and I was like looking at it and taking pictures. And I looked over to my left. And I saw this little white thing. I was like, oh, what's that? So I kind of like walked over to where it was….and it was an eggshell. And so sure enough, right behind where that eggshell was, was the first known burrow that had ever been recorded in Kohala in Western times.
Jessie Eden: Kohala is in the remote northwest part of Hawaii Island.
Bret Mossman: I was like focused on the plant and there was the burrow! And then same thing up here. We found this rare plant and then we found the burrow — and it was less than two meters from where that plant was.You know, so it's like, it's like, so for me there's been this really cool thing where the plants have been showing me where the birds are
[Optimistic music fades out]
Jessie Eden: It took Bret and his team three years of searching to find the first burrow… but at some point, the team realized that they had detected ‘Ua‘u way before all of this… remember that creepy laugh they’d heard in the middle of the night?
Bret Mossman: What we ended up finding out is that it was actually the ‘Ua‘u flying by. So when they fly, their wings make this, like, wah, wah, wah, wah sound. And so it was like we were all kind of creeped out and freaked out about what it was, but it ended up just being the birds we were looking for!
Jessie Eden: The hard work Bret and his team put into these discoveries has been critical in working toward getting protections that the ‘Ua‘u need. Which, no surprise here, is first and foremost— a fence.
Bret Mossman: We then were able to move forward extremely quickly to getting a fence constructed on Mauna Kea. And so that ripple effect of finding this bird is now protecting this large, 90 acre area. That’s going to be the only area in all of Mauna Kea that is restored to a state of almost being completely mammal free.
[Reflective music begins]
We're all connected. What happened in these islands is it changed too quickly for species to keep up. And I think that's where it becomes so important to bring in all aspects of island management. And to really bring in these ideas of Aloha ʻāina, mālama ʻāina, kuleana to place — you know, responsibility, love of the land and caring for the land. That's what needs to happen everywhere.
This is where I'm happiest, with these birds. And I sleep so much better when I know that my ‘Ua‘u is safe and its burrow.
[‘Ua‘u calls from Mauna Kea]
Jessie Eden: The work of studying these ‘Ua‘u is arduous. Their nesting locations are often extremely difficult to reach and the terrain can be treacherous and exhausting. But it all matters.
[Music fades out]
[Fade from ‘Ua‘u calls from Mauna Kea to ‘Ua‘u calls from Lānaʻi Colony; Raucous calls]
Back on Lānaʻi, I sat with Rachel in the misty evening drizzle with our headlamps and rain jackets, overlooking the uluhe ferns where the ‘Ua‘u live.
[Lānaʻi Colony ‘Ua‘u calls]
[Rachel and Jessie giggle]
Rachel Sprague: Just being able to sit here and listen to them living their lives. And, um, just walking up here, knowing that, that all of the other work that we've been putting effort into is making it so, like, this sort of amazing cacophony of birds can just do this and can just live their lives.
Jessie Eden: Although Hawaiian petrel colonies throughout the islands are relegated to high elevation slopes, and the dangers to their wellbeing do persist, hope is high for their continued survival. When we mind the problems we've caused here in the islands, these resilient little seabirds can take care of the rest.
[Reflective Threatened Theme music begins, solo for a few seconds]
Ari Daniel: Thank you for joining us for this season of Threatened in Hawai’i. We’ve unpacked so much about this spray of islands in the middle of the Pacific — and what they have to teach us about birds — the honeycreepers, alala, ua’u… their habitats, and our unavoidable role in protecting it all.
We’re going to take a short break, but we will be back in just a few weeks with more stories about people taking action for birds. We’re heading to another island…Puerto Rico for four more stories, and we’ll be releasing them in English and Spanish. Stay tuned.
This episode was produced by Jessie Eden and me, Ari Daniel. It was edited by Caitlin Pierce of the Rough Cut Collective. Audio mix by Sam Johnson and Mark Bramhill. Fact-checking by Conor Gearin. Our theme song and original music were composed by Ian Coss, with additional music by Blue Dot Sessions. Threatened is a production of BirdNote and overseen by Content Director Allison Wilson. Huge thanks to the whole BirdNote team for their work on this season. You can find a transcript of this show and additional resources, BirdNote’s other podcasts, and much more at BirdNote dot org. Thanks for listening. See you next time.
[Theme music ends]
Mauna Loa and Mauna Kea ‘Ua‘u colony recordings provided by Patrick Hart and the Listening Observatory for Hawaiian Ecosystems (LOHE) Lab at the University of Hawai‘i at Hilo.
Threatened Theme by Ian Coss
“White Caps” by Sam Johnson
“Calisson”, “Hedgeliner”, “Phase Purple”, “Palms Down”, and “Careless Morning (No Rhythm)” by Blue Dot Sessions