for National Geographic News
With hundreds of dead or sick Magellanic penguins washing up along the Brazilian coast in recent weeks, experts are struggling to figure out why so many have been appearing—and why they're so much farther north than usual.
In July and August—winter in South America—it is common for a few dozen young penguins to wash up as far north as Rio de Janeiro state.
That's because each year thousands of the animals living in Patagonia, at the southern tip of South America, swim out to sea in search of fish and get swept up in strong ocean currents that carry them northward.
A few casualties along the way are inevitable, especially among younger birds that are not strong enough to survive pollution, disease, or other incidents.
But this year wildlife officials say they have found about 500 dead or dying birds along the coast of the northeastern state of Bahia—much closer to the Equator than the penguins have ever been found before.
"Global warming is the logical cause," said climatologist Jose Marengo of Brazil's National Institute for Space Research (INPE) and a member of the UN's Intergovernmental Panel on Climate Change.
"Sea currents are a reflection of wind patterns. This winter has started earlier and, so far, has been more severe," Marengo said.
As a consequence, the ocean currents in which the penguins travel can get stronger on particularly cold days, taking the birds farther north.
Still, the South Atlantic is one of the "big holes in climate knowledge" in the Americas, Marengo cautioned. There are no historical statistics that could prove global warming is affecting local sea currents.
Sick and Tired
As of July 30, workers in Bahia were treating 474 sick penguins, said Sheila Serra, a biologist at the Sea Mammals Institute in the state capital of Salvador. In addition, more than a hundred penguins had been found dead in Bahia.
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