Penguins leave Antarctica after summer, but where they go in winter has been a mystery for many years.
But thanks to a tiny location device, scientists have discovered that macaroni penguins do not go sunbathing – they spend winter feeding in the cold southern oceans.
Macaroni penguins are the most common penguin species and one of the top consumers of fish and krill in Antarctica. During the summer they nest in islands surrounding Antarctica, where their breeding and feeding habits are quite well known. But after the moult at the end of the summer, the macaroni penguins disappear from sight.
So what do they do over the next seven months?
To find out, Dr Charles-André Bost and colleagues from the Centre d’Etudes Biologiques de Chizé in France and the British Antarctic Survey, headed out to the Kerguelen Islands, home to one of the biggest colonies of macaroni penguins. The team attached miniature global location sensors to the legs of 21 penguins at the end of the breeding season.
Six months later, the team returned to Kerguelen as the penguins were coming back from the winter migration. They caught 14 of the tagged penguins and managed to download data from 12 devices.
The scientists found that the penguins headed east as soon as they leave Kerguelen and travel long distances, swimming on average about 10,000 km. And none of the birds came ashore during the six months of winter!
The macaroni penguins did not stay together but scattered shortly after departure. Some continued eastbound, while others turned south half way. ‘The penguins did not disperse randomly and stayed within the Polar Frontal Zone, which has seawater temperatures between 1 and 5°C, is the northern limit of Antarctic waters.