Argentine penguins are turning up off the coast of Brazil in record numbers, and a University of Washington scientist believes it is because unusually prolonged cold water has kept their food supply - primarily sardines, anchovies and squid - farther north much longer than usual. The far-distant food supply could be a major culprit in penguin nest failures now occurring in Argentina.
It is not unusual for the annual migration of Magellanic penguins from Punta Tombo, a reserve in Patagonia on Argentina's Atlantic coast, to take them as far north as Brazil, said Dee Boersma, a UW zoology professor and director of the Magellanic Penguin Project. There have been several instances in which unusually cold currents drew the birds farther north than Rio de Janeiro.
"What's unusual is that there are so many of them and so many are going ashore. They are young birds, most of them aren't even a year old," Boersma said. "This is such a cold-water event, with so many fish, that the young have been doing well and surviving. Now they should be heading south, but some of the birds went so far north that they may have stayed longer than the fish did."
While young birds seem to do well in years when the cold water shows up, those same conditions appear to be taking a toll on the birds' reproduction this season. Birds were late in returning to Punta Tombo to breed, and not as many as usual are breeding. They started with 116 nests in September and laid their eggs at the end of October.
"This is the latest breeding season in the 18 years I've been studying penguins at Punta Tombo," Boersma said.
A week ago, her graduate students working in Argentina reported that of the 116 original nests only 39 had not been abandoned. "Some of the females had been sitting on nests for nearly three weeks and were so skinny they had no choice but to desert their eggs," she said.