“Long live”, was the phrase with which the scientists of the Patagonia Program bid farewell to three juveniles of the hooded grebe (Podiceps gallardoi) that had been raised in a scientific base. As they watched the birds drift away in the waters of the estuary of the Santa Cruz River, they felt a glimmer of hope for this endangered species.
The release, carried out this Monday, constituted a groundbreaking event for the conservation of native fauna in Argentina. For the first time, a critically endangered species was released into its natural habitat after being raised in captivity.
Until Sunday, the “Juan Mazar Barnett” Biological Station, where the Patagonia Program of Aves Argentinas works, had been home to the chicks. Due to the absence of natural reproduction of the hooded grebe in the last five years, scientists considered that ex-situ breeding -meaning outside its natural habitat- was the only way to prevent its disappearance.
The challenge of raising the hooded grebe
The hooded grebe was discovered in 1974 by the Argentine naturalist Mauricio Rumboll. The first detected habitat was Laguna de Los Escarchados, near El Calafate, province of Santa Cruz. From the early years, its situation was concerning since only 150 individuals were identified. In the 90s, the International Union for Conservation of Nature (IUCN) considered that the inaccessibility of its habitat ensured its protection. However, over time, the scenario changed.
The predation of invasive species, such as the American mink, and the impact of climate change – with intense winds and drought reducing their nesting sites – led the IUCN to classify this species as Critically Endangered in 2012, the category prior to extinction.
For this conservation program, eggs were collected in the high-altitude lagoons of western Santa Cruz, where the last populations reside. Subsequently, the eggs were transported to the biological station, where they were incubated in controlled environments.
After hatching, the chicks were fed full-time for two months. They were also encouraged to swim since the hooded grebe needs to do so to activate its digestion. Once they reached a weight of 400 grams (males) and 350 grams (females), the three specimens were ready to be released.
Collective effort to save an emblematic Patagonian bird
The estuary of the Santa Cruz River, the territory where the species usually winters, was the setting for this emotional moment. The three juveniles were marked with numbered red rings to facilitate subsequent monitoring. “This action, taken on a larger scale, could mean the difference between extinction and survival,” stated Aves Argentinas.
According to this organization, the driving force behind the project, replicating this process systematically could generate groups of more than 50 juveniles each year, which would be a key reinforcement for the wild population.
The Provincial Agrarian Council provided the boat that transported the birds and will be used in the subsequent post-release monitoring tasks.
In this initiative, aimed at saving an emblematic bird of the Patagonian region, the Provincial Agrarian Council of Santa Cruz, the State Secretary of the Environment, the Municipality of Puerto Santa Cruz, CONICET, Bariloche Foundation, ICFC, and FCEN-UBA also participated.
