First-Ever Release of Captive-Bred Hooded Grebes into the Wild

Argentina is making conservation history: for the first time ever, a globally Critically Endangered species Podiceps gallardoi will be released into its natural environment in Santa Cruz, having been raised in captivity from egg to juvenile.

The chicks were born at the “Juan Mazar Barnett” Biological Station and will be released into the Santa Cruz River estuary. Given the species’ near-total lack of reproduction in the wild, this action — if scaled up — could mark the difference between extinction and survival.

The Hooded Grebe was only discovered in 1974, when Argentine naturalist Mauricio Rumboll first found it at Laguna de Los Escarchados, near El Calafate in Santa Cruz Province. Since then, its story has been one of alternating hope and alarm. Initially thought to be at great risk of extinction, with only about 150 individuals known, the species was later considered somewhat protected due to the remoteness of its habitat — a claim made by the International Union for Conservation of Nature (IUCN) based on data collected in the 1990s by Fundación Vida Silvestre Argentina (FVSA). Unfortunately, this proved incorrect, and human activity, both direct and indirect, reached even the most remote corners of its range.

In 2012, after intensive research in these remote Patagonian landscapes, the Hooded Grebe Project team gathered data that led the IUCN to reassess the species’ status, upgrading it to Critically Endangered — the highest threat level before extinction. The few remaining breeding populations are found on high-altitude plateaus in western Santa Cruz, migrating in winter to large river estuaries, primarily that of the Santa Cruz River.

Since 2010, the Hooded Grebe Project – Patagonia Program, work to reverse this situation in collaboration with provincial and national agencies, NGOs, universities, CONICET, and international institutions, has worked tirelessly to reverse the species’ decline. Key actions include controlling invasive species and mitigating climate change impacts. While these efforts have stabilized the population to some extent, environmental degradation continues, prompting the search for alternative solutions. For the past decade, a team led by veterinarian Gabriela Gabarain has pursued a bold, unprecedented idea: raising Hooded Grebes from egg to release — a first not only for this species but for any grebe in the world.

When science meets patience

In the past five years, wild reproduction of the Hooded Grebe has been virtually nonexistent, despite the ongoing efforts of colony guardians — the project’s field technicians. A decade ago, the idea of ex situ breeding began to gain traction as a potential lifeline for the species. Today, it is clearer than ever: an unprecedented process — and perhaps the most powerful strategy to save it from extinction.

The process began with learning how to collect one of the two eggs typically laid by each pair. Ninety-seven percent of pairs raise only one chick, abandoning the other egg — known as the “insurance egg.” Collecting these eggs is no easy task: strong winds, muddy lakebeds, and cold waters make it a risky challenge — both for technicians and for the fragile nests — requiring highly skilled personnel. Using eggs that would otherwise be lost, and without compromising colony success, the team carefully transports them to the Biological Station. There, specially designed incubators maintain precise temperature, humidity, and rotation. After 21 days, when hatching begins, the eggs are transferred to hatching units. But the real challenge begins after that.

The chicks require near-constant feeding — day and night, 24/7. Literally all the time. They also need to swim to stimulate digestion, requiring synchronized feeding and swimming schedules, as well as appropriate facilities. The team faced nearly a decade of trial and error, turning frustrations into knowledge. To speed up progress, the protocol was tested using eggs from the more common Silvery Grebe, a similar species. In the 2023–2024 season, the team successfully completed the full cycle with Silvery Grebes, leading to high expectations for 2024–2025.

The first ten days are the most critical: accepting food is a vital hurdle. This early-stage fragility also occurs in the wild, showing that the challenge is not only artificial. After over two months of round-the-clock care, three juveniles reached the ideal weight for release: over 350 grams for females and 400 for males.

And the big moment finally arrived

But this, too, brings questions: How? Where? When? The answer came through joint planning among institutions: by releasing the birds directly in the wintering grounds at the Santa Cruz River estuary — alongside adult grebes already present — they avoid the dangerous first migration. The juveniles will be marked with numbered red bands, allowing future monitoring when they return to the breeding plateaus.

A turning point

Captive breeding may alter the species’ fate. Though natural reproduction is nearly nonexistent, eggs are not lacking — most fail to hatch due to strong winds. Collecting and raising them under controlled conditions could yield yearly cohorts of over 50 juveniles — a crucial reinforcement for the wild population.

This strategy has already saved other species, like the Giant Panda and California Condor. But as with those cases, making this effort sustainable for the Hooded Grebe depends on strengthening available resources and building strong partnerships among the many involved institutions: the Patagonia Program of Aves Argentinas, Santa Cruz Provincial Agrarian Council, the State Secretariat for the Environment, the Municipality of Puerto Santa Cruz, CONICET, Fundación Bariloche, ICFC, FCEN-UBA, and many more.

The path ahead is uncertain — but for the first time in a long while, there is a real, tangible hope of avoiding the extinction of the Hooded Grebe, a symbol of Santa Cruz, Patagonia, and Argentina itself.

Text: Aves Argentinas