Running Wild: The Return of Patagonia National Park’s Rheas

The Chacabuco Valley stretched wide before us. The golden steppe was broken by winding rivers, framed by snow-capped ridges that seemed to glow in the fall sun. We were in the heart of Patagonia National Park, a place reborn from what used to be one of the largest sheep ranches in Chile. Old Estancias once carved the land into squares made of barbed wire and filled with overgrazed pastures. But today, those fences are gone. The grasslands pulse with guanacos again and the park has become a symbol of what rewilding can mean when it’s done right.

We’d come here to see a beacon of rewilding in the area, which took shape as an oddly familiar looking species of bird called the Darwin’s rhea (known locally as ñandú or choique.) It’s Patagonia’s strangest survivors, this flightless animal with legs built for speed and feathers streaked in soft browns that disappear into the grass. From a distance, they look almost prehistoric, like something you might imagine darting across the steppe in a bygone epoch. Up close, they’re ecosystem engineers, spreading seeds that shape grassland health, and feed predators such as pumas and foxes that depend on them for survival.

These birds possess an unusual way of fertilizing the land, making them critical players and worth a heavy invesment in their rewilding. Unlike guanacos, which use fixed latrines (skat dropping areas) that concentrate nutrients in one spot, rheas are wanderers in every sense. As they roam, they drop seeds across the steppe in a steady scatter, with each pile of droppings carried further by rodents like tuco-tucos that burrow and churn the soil. This gives plants a chance to take root in Patagonia’s harsh winds. It’s a less prominent, yet highly fundamental cycle where rheas eat, move, fertilize, and in doing so, stitch the landscape together. Without them, the steppe would grow weaker and far less resilient.

Rheas, standing about three feet tall, are designed to vanish into Patagonia’s grasslands rather than dominate them. Rheas move almost like ghosts, disappearing into the landscape until you realize the ground itself was alive and moving all along. And yet here, in what should be one of their strongholds, rheas had nearly vanished. 

Just a decade ago, a survey inside the park found fewer than 22 individuals left—a catastrophically low number for a bird so integral. The reasons were painfully manmade, as they often are when it comes to biodiversity loss like this. Decades of ranching, which ended here in 2008, had blanketed the valley in fences that trapped and killed rheas. Eggs were taken for food, chicks were chased down, and their range shrank until they were pushing just shy of a memory.

That’s where Emiliana Retamal, a young veterinarian turned wildlife ranger, comes into the conversation. She’s part of a small team with Rewilding Chile trying to bring rheas back to the Chacabuco steppe. The first thing she said upon meeting was to slow our movements, talk less, and to follow her lead when approaching these flightless wonders. We were off to the holding pens that served as a temporary home for both rhea adults and chicks, known here as charitos. Some of them were getting ready to be released into the wild, marking another historic moment for the rewilding team.

The following morning was all about getting things right. Rewilding Chile’s rhea initiative, called Ñandú Conservation and Recovery Programme, has been running since 2014. Ever since, the team has been incubating eggs, raising chicks, slowly reintroducing birds into the wild, all building toward a goal of restoring a self-sustaining population of at least 100 adults and at least four actively reproducing.

For Emiliana, release days are equal parts research, nerves, and a ton of hope. Each bird is carefully prepared, including mandatory health checks, parasite treatments, and a period of acclimatization inside open-air pens where they gain strength and learn to fend for themselves. The idea is not to domesticate them in any way, but rather, give them just enough of a head start to survive top predators, and Patagonia’s harsh winters once the pen gates swing open. Some are fitted with GPS collars—the first of their kind for monitoring rheas here—allowing the team to track their survival rates and see if they’re reproducing in the wild.

We were fortunate enough to witness this particular relase, which was a true milestone. Alongside captive-born birds, a group of 15 rheas had been translocated from Argentina for the first time. These wild individuals were specifically brought in to bolster genetics. These bird groups act quite differently, with the wild ones moving as a tighter group and demonstrating discomfort around people. That’s exactly what Emiliana wants, as the goal is to ensure the animals remember what it means to be wild or remain entirely wild to up their chances of survival.

When the moment finally came, the puesto (or field station) buzzed with controlled urgency. Emiliana and her patchwork team of rangers, vets, community leaders, and allies, moved with practiced rhythm, coaxing these powerful, awkward-looking birds into small wooden crates. These rheas were not tame, so asking them to willingly go into confinement requires a patient and steady hand. Every movement was about safety—maximizing calmness while minimizing stress, and avoiding injury for all.

Outside, a convoy of trucks rumbled to life while drones circled high above, ready to follow the release. Autumn had painted the surrounding forests in fire-reds, yellows and oranges. The air carried the kind of crispness that warned of winter’s approach. Bundled in layers, we set off across the park along a road that wound through valleys where iconic mountains dominated the horizon. The landscape begged us to stop and stare, but the mission pushed us forward. When we reached the release site, the cages were lifted down and arranged side by side. The team stood in a nervous silence. Everything was ready, so the countdown began.

On the count of three, the gates opened and the wranglers stepped back fast. For a heartbeat, not a single bird moved. Then, with a rush of feathers and legs, the rheas spilled out into the open, scattering across the grasslands like wind made visible. Some lingered, hesitating at the threshold. Others bolted in tight groups, vanishing into the tawny steppe. It certainly was not graceful, but it was emotional nonetheless. A species that had nearly disappeared from this place was running free, once again.

Releases like this may look simple. Open the gates, let the birds run, right? But the reality is far from it. Rewilding is hard work, and with rheas, it’s closer to brutal. In the wild, more than half of chicks don’t survive their first year. Eggs are eaten by predators or trampled by livestock, chicks are picked off by foxes, eagles, and pumas, and even curiosity can be fatal. Young birds often die from mistaking the wrong thing for food, like rocks or other inedible objects. And on top of that, the male birds are sometimes left caring for 50 chicks at once, making survival that much harder. Add to that the genetic bottleneck of starting with so few individuals in the wild, and every single bird that makes it into adulthood feels like a victory against impossible odds.

That’s why Emiliana and her team treat each rhea like an individual case study. Every release is followed by weeks of long days in the field monitoring and collecting data. Collars on individuals provide glimpses of survival, but much of the knowledge still comes from old-fashioned ranger work of tracking footprints across the steppe. Their job next will be to spot birds from a distance, asking local police and community members to report sightings to speed up the process.

And yet, for all the setbacks, the progress is undeniable for this team. From a ghost population of just 22 individuals to more than 70 now roaming the Chacabuco steppe, the recovery is indisputable. But numbers alone aren’t enough around here. Survival depends on genetics, and until recently, most of the birds released here had been hatched or raised in captivity. This means they were strong in body, but softer in instinct. This release however, was marking a turning point.

These 15 wild rheas translocated from Argentina to Puesto Ñandú—just a few kilometers from the border—arrived carrying what captive-bred birds could not: diverse DNA, sharper instincts, and that memory of how to live without the aid of humans. While borders divide people, they mean nothing to the animals who cross them freely. Rheas don’t recognize Chile or Argentina, but they recognize habitat. And if this recovery is to last, it will take both nations working together to protect the grasslands they share.

Even with the numbers trending upward, one of the biggest challenges is, of course, social. In nearby Cochrane, Emiliana is known casually as “the choique girl.” People are aware of the project, but they don’t always feel ownership of it. Many still see the park as something created by outsiders, disconnected from their lives. That gap is fundamental, and something the Rewilding Chile team, as well as its other collaborators including Quimán Reserve, CONAF (Chile’s National Forestry Corporation), SAG (Agriculture and Livestock Service) and Carabineros de Chile, are putting emphasis on. Rewilding efforts must be equally about saving species and building genuine relationships with communities or everything done in the field will not be effective.

Being in attendance on that release day, standing in the steppe as the cages opened and rheas burst back into a landscape that once nearly lost them, was something that will never escape our memory. The pride on the team’s faces, the outward relief after months of preparation, the sight of those birds vanishing into the golden grasslands, all felt triumphant.

As Emiliana reminded us, this is only the beginning. In the vastness of Patagonia National Park, surrounded by snow-capped ridges and rivers that once ran through sheep pastures, the work ahead is as immense as the landscape itself. Watching rheas roam free again was proof that rewilding means to restore the past, in addition to defining a new future, where ecosystems can someday thrive without our intervention.

Written by: Andi Cross

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ABOUT THE AUTHOR

Andi Cross is an explorer, strategist, and extended range diver with Scuba Schools International and Scubapro, who leads Edges of Earth—a global expedition and consulting collective documenting resilience and climate solutions across the world’s most remote coastlines. Her work centers on “positive deviance”—spotlighting outliers succeeding against the odds—and using storytelling and strategy to help scale their impact.