Dozens of freshly cleaned Magellanic penguins waddled into the ocean Monday to the applause of onlookers, the first batch of close to 200 goo-covered birds that were rescued and washed after an oil spill.
The 49 penguins, each tagged with metal identifying bands, were released on a wind-swept South Atlantic beach not far from the outlet of Argentina's River Plate. Another 141 birds that survived an unexplained oil spill off Patagonia in May still await release.
About 220 penguins were found alive in remote Santa Cruz province following the spill, but some later died. The 190 survivors were airlifted to Fundacion Mundo Marino, a marine facility in San Clemente del Tuyu, some 185 miles (300 kilometers) southeast of Buenos Aires.
There the migratory seabirds were repeatedly washed until their bodies were rid of the sticky oil and their feathers realigned to regain their waterproofing against the chill of the South Atlantic ocean, experts said.
About 50 tourists, some waiting for hours, cheered as the caged penguins were brought to the shore in two pickup trucks. They were freed en masse and raced past the tourists, disappearing in seconds under the waves.
"Beautiful! Beautiful!" someone shouted as video cameras whirred. The birds could be seen swimming away from the coast and then they vanished in the distance.
"This makes it all worthwhile," said Valeria Ruoppolo, a veterinarian with the International Fund for Animal Welfare who helped rescue the birds along with government experts from Santa Cruz and teams from the Fundacion Mundo Marino.
Ruoppolo said another 50 penguins would be released sometime before Friday with the rest returning to the sea in coming weeks.
Although the source of the May oil spill was never determined, she said it could have been an offshore ship dumping engine oil and other pollutants. Ruoppolo said penguins are wide-ranging migratory seabirds whose routes make them vulnerable to spills.
In early May, penguins coated in black oil began showing up on rocky coasts off South America's southern Straits of Magellan. Authorities first reported that 70 dead Magellanic penguins were found at the Cabo Virgenes nature reserve on the Straits, 1,350 miles (2,150 kilometers) south of Buenos Aires. About 400,000 penguins live there during the warmer months.
Coast Guard authorities sent overflights but could not detect the source of the oil.
"Having all these ships throwing their oil in the water ... it causes a big problem," Ruoppolo said, adding hundreds of penguins were found dead "but the real number we'll never really know."
Ruoppolo said rehabilitation efforts at the initial rescue site near Rio Gallegos, in frigid Santa Cruz province, were hampered by the cold. A decision was taken to airlift birds to San Clemente del Tuyu with its warmer weather, speeding up the recovery process, she said.
The birds regained their waterproofing through a painstaking process of repeated washings and dryings that realigned feathers, she said.
"To regain their waterproofing, they need to get wet and dry off many times. This is how they align their feathers to the normal position, so the feathers interlock together and form a barrier against the cold water," Ruoppolo said.