Patagonia Penguins Make a Comeback

Hillary Mayell
for National Geographic News
December 26, 2001

It looks like good times for the penguins of Patagonia. Magellanic penguins living along the coast of Argentina have suffered two disastrous breeding seasons, but this year the beaches are filled with fat adults and numerous chicks.

Dee Boersma, a conservation biologist at the University of Washington, is spending the holiday season on the beaches of Argentina. But unlike the sunbathing multitudes, she is looking forward to a few weeks in Punta Tombo, knee-deep in waddling penguins, and another couple of weeks with the penguins of Antarctica.

She has been tracking penguins as part of the Wildlife Conservation Society's (WCS) Magellanic Penguin Project since 1983. The Exxon/Mobil Foundation provides a great deal of the funding.

Between 1987 and 2000, the Magellanic penguin population in Patagonia suffered a 30 percent decline, primarily due to overfishing, pollution, and climate change. This steady decline became even more alarming in the face of two disastrous breeding seasons.

In 1999, 85 percent of the chicks in the Punta Tombo colony died in a severe December storm; the majority of the chicks born in the 2000 breeding season died of starvation. Adult penguins didn't fare a lot better. Several thousand were found dead along the beaches in two die-offs.

"In October [2000] they probably died of starvation," said Boersma. "The cause of the second die-off in December is less clear. It could have been a virus, but what we had were healthy penguins leaving on foraging trips. I think it's much more likely they were victims of a toxic algal bloom."

The extreme reduction in the penguin's favorite foods—squid, hake and anchovy—is likely the result of an increase in commercial fisheries in the South Atlantic and the change in ocean fish populations caused by climate change.

But this year the birds are fat, the eggs goose- rather than chicken-size, and pairs that haven't bothered to breed in several years are laying eggs. The October nest survey showed a 28 percent increase from 2000, the highest number of active nests since 1987 when the surveys first began.

Boersma is on her way to Argentina to see how the chicks are faring and to attach 14 new satellite tags.

The Problem with Bachelors

Magellanic penguins spend six months at sea in the waters of the South Atlantic Ocean. They return to the rookery where they were born each spring—September in the Southern Hemisphere—to meet up with their mates and breed.

Following an elaborate courtship ritual, eggs are laid—two in a good season—and the parents take turns sitting on the nest over the 42-day incubation period. The male goes foraging for two weeks, returns, and then the female goes foraging for about the same amount of time. Once the chicks hatch, parents alternate, one day foraging, one day guarding the nest. They are fierce defenders of their young, protecting them from numerous predators that feed on eggs and chicks, including birds—skuas, southern giant petrels, and gulls—and land critters like armadillos, skunks, and foxes.

Continued on Next Page >>


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