Hundreds of dead Magellanic penguins have washed ashore on beaches in Brazil this month, animal experts say.
At least 500 have been reported in the Peruibe area, The Christian Science Monitor reported. The city is south of Sao Paulo.
Rafael Ramos, a veterinarian at the Peruibe Aquarium, said penguins he has necropsied have no food in their stomachs.
"They come on the currents looking for food," he told the Monitor in a phone interview. "Many of them are young and inexperienced and when they don't find food they keep coming with the currents and eventually find themselves in Brazilian waters."
The penguins breed on the coast of Patagonia in southern Argentina in the southern summer. They spend the winter at sea hunting for fish.
Some researchers believe La Nina has caused fish to move from the Southern Atlantic to the Pacific coast of South America, leaving less fish for the
penguins. Others say long-term overfishing threatens the birds.
Officials at Niteroi Zoo near Rio de Janeiro said the number of penguins washing up on beaches in that area appears to have increased, with 1,000
birds given to the zoo for rescue in 2008.