Photo above: Amy records a soundscape during a reporting trip to Kenya for Season 5 of Threshold. Credit: Jed Allen

In a world dominated by human voices—buzzing highways, endless notifications, the hum of urban life—it’s easy to forget that Earth is alive with countless other sounds. From the songs of whales to the crackle of coral reefs, the natural world is a symphony we’re often too distracted to hear. Yet, as noise pollution rises and ecosystems face unprecedented threats, listening to these nonhuman voices has never been more critical. This idea is at the heart of the 5th season of “Threshold,” a Peabody Award-winning podcast exploring the profound connections between humans and the natural world.

Founded by journalist and storyteller Amy Martin, “Threshold” has captivated audiences with its immersive, field-based reporting and commitment to complexity. Each season tackles a pressing environmental story—whether it’s the reintroduction of bison to the Great Plains or the fight to protect the Arctic National Wildlife Refuge. 

Season 5, titled “Hark,” takes listeners on a journey into the realm of sound—investigating what it means to truly listen to the nonhuman voices that surround us. From frogs to dolphins, coral larvae to elephants, the season explores how sound shapes ecosystems and how we might reconnect with the world through the simple, yet transformative act of listening.

Bioneers Media Producer Emily Harris recently sat down with Amy Martin to discuss her process, the inspiration behind “Hark,” and the unique challenges and joys of bringing nonhuman soundscapes to life. Drawing on her expertise as a sound engineer and storyteller, Emily explored how Amy’s work creates profound connections between listeners and the natural world.

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EMILY HARRIS: Your work is such an immense project, and it’s incredible how you bring listeners into the field—something you don’t often hear in podcasts. You describe your experiences beautifully and really transport us to the worlds you’re observing. Can you share more about your process and how your team brings these stories to life?

AMY MARTIN, “THRESHOLD” FOUNDER: I’m so glad you mentioned being out in the field—that’s such a huge part of why I started “Threshold.” I’ve always loved audio, even as a kid. I grew up listening to “Morning Edition” and “All Things Considered,” proudly flying my nerd flag early and strongly.

Growing up as a farm kid in rural Iowa, audio captivated me because it allowed me to travel to Zimbabwe, Poland, or some fascinating part of the U.S. before I even left for school. That’s what audio storytelling is for me: the power to take people places.

I feel there’s a real shortage of storytelling grounded in place and on-the-ground reporting. There’s so much incredible work we can do in studios—interviews, imaginative storytelling—and a lot of our production happens there too. But there’s something so vital about connecting listeners with actual places and people out in the world. Talking remotely, as we’re doing now, is magical, but it’s entirely different from being physically present in the environment I’m describing.

You’re right that it’s unusual for a podcast to take this approach. It’s expensive, time-consuming, difficult, and hard work—but it’s also wonderful. I believe it’s part of what makes “Threshold” special, and it’s something I never want to lose.

Ultimately, I feel that if “Threshold” can’t include these on-the-ground reporting trips, then there shouldn’t be a “Threshold.” That’s what the show is at its core.

EMILY: Your show creates a bridge for people to experience the natural world even if they may never physically visit. I’m curious about how belief and understanding are shaped by experience. Have there been moments in your work where being present in a place changed what you thought you knew?

AMY: What comes to mind for me is how much easier it is to think we know something about a place, a person, a group, or even animals—until we get closer. Proximity has this way of revealing complexity that we just can’t see from a distance.

A couple of examples from my work stand out. In the upcoming season, listeners will hear from elephants in Northern Kenya. Elephants are enormous and incredible, and this season is all about sound and listening. But while I was there, trying to record elephants, the loudest voices weren’t the elephants at all—they were frogs. It was almost comical. I couldn’t see most of the frogs, but their voices dominated every recording. While I watched majestic elephants, my tapes were filled with the constant, almost comical, sound of frogs drowning everything else out.

Another example is from season 3, which focused on the Arctic National Wildlife Refuge. I spent time in Kaktovik, the Iñupiat village closest to the proposed oil and gas drilling sites. People often presented this narrative that Gwich’in communities on the refuge’s south side oppose drilling, while Iñupiat communities in Kaktovik support it. But on the ground, it wasn’t that simple. I talked to people who were pro-drilling and framed it as a matter of Indigenous sovereignty—this is our land, and we get to decide. Others in the same community felt the same about sovereignty but were firmly against drilling. Proximity shattered the binary and revealed a far more nuanced reality.

That’s what I love about this work: proximity brings complexity, and complexity reveals unexpected voices—like loud frogs or quiet elephants. It also surfaces perspectives that don’t fit neatly into categories, and that’s a good thing. I aim to bring that kind of proximity and complexity to listeners because it works on us in powerful ways.

EMILY: Your show masterfully invites curiosity and challenges preconceived notions without overwhelming listeners with assumptions about climate change. Was it a conscious choice to focus on the relationship between humans and the natural world in the way you write, produce, and approach your topics? How do you bring listeners into that connection so effectively?

AMY: To start, I completely understand why you’d think the foundation of the show is climate change, but it’s actually not. Of course, every environmental story is ultimately a climate story right now; it’s inescapable. Whether we’re talking about school lunches, banking, or biodiversity, it’s all connected. But the foundation of the show is really about the relationship between humans and what we call the “natural world.”

That term itself—“natural world”—reflects such a deep arrogance, doesn’t it? As if there’s this whole category of existence that’s separate from us. What I aim to do with the show is tell stories that help knit back together what we imagine has been pulled apart—or better yet, start from the assumption that it was never truly separate and see what unfolds. 

As for bringing listeners in without hitting them over the head, I think it comes down to storytelling. When we’re talking about climate, biodiversity loss, or species reintroduction—like our first season on bison—it’s not interesting to lecture people or rely on narratives where the outcome is obvious from the first sentence. That’s just not engaging to listen to or create.

At the same time, I’m very conscious of not falling into false equivalencies or “both-sides-ism” that avoids taking a stand when it matters. There’s a version of making space for different perspectives that can feel like wimping out, and I don’t want to do that. But there’s also a version of storytelling that pushes an agenda so hard it eliminates complexity and the opportunity for surprise—for people to find common ground or for unexpected truths to emerge.

But there’s also a version of storytelling that pushes an agenda so hard it eliminates complexity and the opportunity for surprise—for people to find common ground or for unexpected truths to emerge.

I aim to work in a space that feels like a third path—between pushing an agenda and retreating from responsibility. When something feels unjust, and there’s evidence to support that, we’ll address it. But even then, I want to invite people into the conversation rather than shutting them out. It’s about creating room for thoughtfulness and connection, even in the face of difficult truths.

EMILY: This season of “Threshold” is called “Hark,” and it’s focus on sound feels so immersive and encourages listeners to slow down in a fast-paced world. Is that something that comes naturally to you—slowing down and embracing silence—or is it something you’ve cultivated through your work and experiences?

AMY: I have to laugh because if you asked the people around me, they’d probably say, “Slowing down? Not exactly her strong suit.” I can practically hear my partner teasing me about needing to slow down.

So, no, it doesn’t come naturally. I tend to approach things full speed ahead. But slowing down is something I’ve consciously worked on, and sound has played a big role in that.

One reason I wanted to focus this season on listening and sound is because sound has always been one of the few things that can stop me in my tracks—in the best way. Long before I became an audio producer, I was just a curious kid struck by the sounds around me. Growing up on a farm, I have vivid memories of the voices of the sheep we raised. Those sounds are so clear in my mind even now. Sound has always been this connective thread for me, as I think it is for so many people.

This show isn’t about slowing down because I’m naturally calm—it’s because I love how it feels when I make space to listen. Sound is such a powerful way to connect, and it’s been profoundly grounding for me in difficult times. It’s not about hearing a bird and suddenly feeling happy, but about that subtle reminder that we’re not alone in this world. There are other beings here.

There’s such an imbalance in our lives right now. We’re constantly surrounded by the voices of our species—media, machines, roads. I know I need to hear other voices. If a single person wandered around talking only to themselves, we’d think something was wrong. But as a species, that’s what we’re doing. I think we need to consider what that’s doing to us.

EMILY: Beyond your personal connection to sound, what inspired you to focus on it for this season? Why does now feel like the right time to explore sound in the natural world?

AMY: The personal connection I have to sound is a big part of it, but honestly, I could have chosen to focus on sound in any season—season one or twenty. What makes now feel especially relevant is the unique moment we’re in when it comes to sound in the natural world.

On one hand, we’re filling the world with more and more of our own noise, and it’s having real, devastating impacts on ecosystems and species. Sound is essential for communication and survival for so many animals—whales, birds, and countless others. This noise pollution is a major problem, even contributing to the extinction of species we cherish. But it’s also a fixable problem, which gives me hope.

At the same time, we’re in an exciting era of breakthroughs in bioacoustics. The equipment for long-term sound recordings is now more affordable, smaller, and easier to deploy than ever before. Ten years ago, setting up microphones deep in the Amazon or the middle of the ocean would’ve been almost impossible. Now, researchers can leave recorders in remote locations for months, even a year, capturing extraordinary soundscapes.

For example, in Australia, there are desert areas that come alive for just a few weeks after rain. Creatures arrive en masse, creating a symphony of sounds, but it’s the hardest time to physically access those places. Now, researchers can leave microphones in advance and discover that instead of five species of frogs, there are thirty. These recordings are uncovering so much biodiversity we never knew existed.

Even more exciting is how AI and machine learning are helping us analyze these recordings. People are dreaming of tools like a “Google Translate” for animals, where one day we might decode the meaning of an elephant’s call. While we’re a long way from that, the potential is incredible. Of course, none of this would make sense without the fieldwork to understand animal behavior and context, which adds layers of complexity and richness to the data.

It feels like we’re at a moment with sound that’s akin to the invention of the microscope in the visual world. For centuries, we tried to understand the natural world by looking at it, and then suddenly, microscopes revealed cells—a whole hidden universe. With bioacoustics, we’re uncovering the hidden worlds of sound and communication in nature.

This moment is poignant. We’re dominating the global soundscape, sometimes silencing species permanently, but we’re also on the cusp of listening in ways we never imagined. The hope is that these recordings won’t just document what we’ve lost—they’ll inspire action to protect and preserve these voices. Many researchers working in bioacoustics are driven not just by scientific curiosity but by the hope that this work will reconnect us to the magic of the natural world and encourage us to cherish it more deeply.

That’s why now feels like the right time for this season of “Threshold.”

We’re dominating the global soundscape, sometimes silencing species permanently, but we’re also on the cusp of listening in ways we never imagined.

EMILY: The coral reef project you covered was fascinating, especially the idea of using recorded reef sounds to encourage repopulation. How did you come across this research, and as a musician, what was it like to explore the interplay between sound and the natural world in this context?

AMY: I can’t remember exactly when I first heard about the coral reef playback experiments—maybe a year or two before I started working on this season. But it immediately struck me as incredible research.

The interplay between fish populations and corals is fascinating. Corals lay down the skeletal structure of reefs, while fish bring in the sounds that give these ecosystems their vibrancy. What’s even more amazing is that coral larvae—tiny planulae, just barely visible to the naked eye—extend tiny cilia, little hairs that can detect sound vibrations. It’s essentially the same mechanism inside our cochlea, the part of our ears that processes sound. That connection is mind-blowing to me.

Corals are such ancient organisms—some of the oldest on Earth. There are many species, but they share this incredible longevity. Even if coral reefs were completely healthy, this kind of research would be worth doing. These reefs are biodiversity hotspots, and there’s still so much we don’t know about them. They hold immense beauty, mystery, and lessons we haven’t even begun to uncover.

At the same time, coral reefs are among the most endangered ecosystems on the planet. Their decline impacts not only marine life but also fish populations, communities living on coral islands, and cultures that have relied on reef-based hunting and subsistence for millennia. It’s heartbreaking and awe-inspiring all at once.

In many ways, coral reefs encapsulate the dual narrative I often encounter in my work: profound beauty and scientific wonder intertwined with deep environmental loss. 

EMILY: Are there actions or practices in your own life, like listening to non-human sounds, that inspire you and might encourage others to connect more deeply with the natural world?

AMY: I always feel a little stumbly when it comes to suggesting actions or practices, but thinking about this season makes it easier because it’s so focused on listening. Unlike other seasons, which were centered on human conflicts, this season turns the microphone toward non-humans. Human conflict isn’t absent, but it’s not the main focus this time, and that shift feels significant.

So here’s what I would propose: think back on your day. How many non-human voices did you hear? How much did you pay attention to them? Did you hear any sounds today that weren’t made by humans? How long did you listen to them, and how did that make you feel? It might have been the meow of a cat or the buzz of a fly—sounds we often overlook or dismiss. Instead of swatting the fly away, consider: what is that sound saying? Who else is hearing it? 

This small practice of tuning into non-human voices can open you up to a richer, more connected sensory experience of the world.

We’ve become almost numb to the dominance of human-made noise—airplanes, highways, shipping traffic—and it’s not about dwelling on the unpleasant, but noticing how much it intrudes and asking: what would it feel like to hear something else? This small practice of tuning into non-human voices can open you up to a richer, more connected sensory experience of the world.

What’s also exciting is how this season connects us to the story of sound itself. We’ve designed the narrative to loosely follow the evolutionary timeline of sound on Earth, starting 4.5 billion years ago and moving up to the present. Right now, in the season, we’re exploring some of the earliest sound creators and listeners—corals, fish, the first land animals.

And here’s the cool part: those first land animals weren’t some dog-like creature. They were arthropods—tiny critters we often overlook or find annoying. These were the first inventors of song on land, and plants joined the soundscape as both listeners and creators.

But I have to admit, as mammals, we crave the complexity of mammal communication. So even though dolphins come much later in the timeline, I decided to sprinkle them throughout the season. I couldn’t resist—it was too fun working with dolphin scientists, and their vocalizations are fascinating. It’s like a little “dolphin spice” woven into the season, offering glimpses of what’s to come.

This exploration of sound is such a joy because it connects us to the vast history of life on Earth while inviting us to listen more deeply to the present. And I hope that encourages others to tune in, too.