Restoring the Darwin's rhea to the Patagonian steppe

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Photo: Tompkins ConservationPhoto: Tompkins Conservation
By Caterinna del Río Giovannini

It is easy to misinterpret the conservation status of the Darwin’s rhea (Rhea pennata), a species that inhabits the wide and extensive Patagonian steppe of southern Chile and Argentina.

Do such vast stomping grounds that encompass thousands upon thousands of hectares make that a lucky home base for this freaky-looking bird with its elongated neck and tiny head? Potentially, yes. But the reality is their large habitat means that the Darwin’s rhea specimens of reproductive age are often scattered and isolated from each other, putting at risk the genetic diversity of the species. In addition, the extensive grasslands of the Patagonian steppe are targeted for livestock grazing, generating stiff competition for their mostly herbivore diet of salt bush, grasses, and cacti fruits.

Better known by its Spanish name “ñandú,” it is a bird that stands up to a meter high and weighs as much as 25 kilos, has a life expectancy of about 11 years, and has three fingers instead of two like the ostriches. Despite their large wings, it is a flightless bird that instead uses their wings to run at speeds of up to 70 kilometers per hour – an effective trait for outrunning predators like pumas, and foxes. But when speed isn’t enough, it deploys sharp claws for defense.

In Aysén, for years the systematic loss of their habitat in this region due to livestock ranching hit this species hard, with just 18 specimens left by the year 2015 at Chacabuco Valley, now part of Patagonia National Park. This tiny band was also separated by almost 200 kilometers from the nearest other Darwin’s rhea population at Baño Nuevo ranch near Coyhaique.


Photo: Tompkins ConservationPhoto: Tompkins Conservation


The situation was worrisome, but thanks to the creation of the Ñandú (Darwin’s rhea) Reproduction Center at Patagonia Park in Aysén, the fate of this species in Chile is changing. Over the past five years, the Tompkins Conservation team has been working closely with Chile’s national park service (CONAF) to strengthen the wild population of Darwin’s rhea.

Tompkins Conservation’s Rewilding Program carried out within the park has the mission not only to expand the population in numerical terms and in geographical distribution, but also is striving for the ñandú to regain its role in the ecosystem. They hope to again see a thriving ñandú population in the region that allows it to interact with other species, benefiting the steppe through dispersal of seeds or associating with guanacos to monitor and prevent puma attacks.

During 2020, the organization says that 10 specimens of ñandú  were reproduced naturally and six through artificially incubated eggs brought from another healthy wild population "that way we increase the number of charitos (baby rhea) that the center produces,", Cristián Saucedo, a veterinarian and director of the Rewilding Program, told Patagon Journal. Once they are born, they are given to the males of the species, who are in charge of incubating the eggs for 40 days and then taking care of the young. "We use the strong parental instinct that the ñandú have. The males are the ones who incubate and give all the parental care. The charitos are super delicate and vulnerable to low temperatures, they are born with a thin plumage that makes them totally dependent on the father," he explains.

The overall goal: to continue supporting the recovery of the species until it reaches 100 wild adult specimens inside Patagonia National Park. And they are on the right track, in just five years the ñandú have multiplied to a population of 70 in the Chacabuco Valley. For Cristian "half of the work is already done, when we reach 100 specimens, we estimate that the population will be in a position to perpetuate itself and prosper without further intervention.”