About 100 oil-coated Magellanic penguins have turned up dead in recent weeks off the coast of Argentina, most in a nature reserve near the frigid southernmost tip of Patagonia.
The Argentine Coast Guard said it was sending flights in search of oil spills, but reported finding none that could have caused the birds coated in black crude to begin arriving on shores off the Straits of Magellan.
"This is very worrisome. We don't know the source," said Francisco Anglesio, environmental undersecretary for Santa Cruz province, where the deaths occurred and the nation's center for oil production.
Authorities reported some 70 of the dead penguins were found at the Cabo Virgenes nature reserve on the Straits in the remote province, 1,350 miles south of Buenos Aires.
But environmentalists said they also found 31 of the wide-ranging migratory penguins dead some 375 miles southeast of Buenos Aires.
Workers have organized a rescue mission, setting up care centers in both locations for some 110 surviving penguins.
40-day recovery for survivors
In Santa Cruz, workers with gloves are carefully removing oil from the birds and placing them in pens.
"We are giving them food if they will accept it and hoping they will recover their strength. But we have to wait," said Jorge Serra, one of the rescue workers interviewed on local television.
Carla Poleschi, at the environmental group Fundacion Patagonia Natural, said the surviving birds will undergo a treatment process that could take up to 40 days.
As an organizer of rescue groups in Santa Cruz, she said workers would spend the first week wiping away oil and gingerly feeding the birds through plastic tubes. She added the penguins were being kept in heated pens to recover from hypothermia.
Oil spills are reported by environmentalists to have caused thousands of penguin deaths over the years. But so far, the mystery of the current spill remains unresolved in an area where dozens of oil-drilling platforms and operations are based.
"We have asked businesses that operate in the area to carry out ... tests to determine if it's possible that some of their pipes have a leak," Anglesio said.
Oil can cause respiratory problems and destroy the insulating properties of penguin feathers, leading to the rapid loss of body heat. To stay warm, the birds head toward shore, where they can eventually die from starvation.
40,000 killed in 1992
"This is a very tragic accident," Poleschi said. "While the number of penguin deaths in the past have been high, reaching 40,000 in 1992, we have not seen an incident of this magnitude in many years."
The last reported oil spill along the Strait occurred last September, killing some 40 penguins.
Rescuers are hopeful that because the migration period is now ending — and the majority of the penguins have reached the coast, they will not find any more oil-soaked penguins in coming days.
The penguins migrate thousands of miles each year, leaving Antarctica from September through the end of April to escape the southern hemisphere winter.
Some 1.8 million breeding pairs are estimated to nest in rookeries off southernmost South America and the Falkland Islands, a neighboring South Atlantic archipelago. Typically they live in burrows and feed offshore on fish on the Pacific and Atlantic coasts.