Wildlife

Thousands of Female Penguins Are Being Stranded in South America

Female Magellanic penguins — a mid-size species of black-and-white bird native to South America's Patagonia region are vanishing from their nests. When not breeding in the latter part of the year, both male and female members of the species migrate north toward Uruguay and Brazil to hunt for the tasty anchovies that call those waters home. Over the last decade, however, scientists have observed an upsetting trend: some penguins are swimming too far north — sometimes hundreds of miles away from their breeding grounds — and getting stuck there.

According to a new study published today in the journal Current Biology, every year, thousands of Magellanic penguins fail to return home from their migrations. Some become stranded on the shores of Uruguay, Argentina and Brazil. Others wash up already dead, their stomachs empty or polluted with plastic waste. Strangely, about two-thirds of the stranded birds are female.

During their spring and summer migrations, male penguins tended to dive deeper and stay closer to their Patagonian breeding grounds; female penguins swam closer to the water's surface, but migrated significantly farther north than their male counterparts.

There, in the waters near Uruguay and southern Brazil, the penguins approached known penguin-stranding hotspots. According to the researchers, these stranding sites — such as the riverfront near the city of Buenos Aires, in northern Argentina — likely trap the penguins through a mixture of strong currents that prevent smaller-bodied birds from swimming home.