On the Danger Islands of Antarctica, researchers have discovered one of the world’s largest colonies of Adélie penguins, harbouring more than a million birds of a species long thought to be succumbing to changing weather patterns and dwindling food supplies. The Adélies are dressed by nature in formal black and white. Their eyes are rimmed by distinctive white rings that resemble spectacles. And in recent decades, their fortunes have shifted with long-term changes in the annual ice conditions on which they depend, with eight or more colonies along the Antarctic Peninsula vanishing. For that reason, the discovery of such a large new colony surprised some scientists. Researchers led by ecologist Heather Lynch at Stony Brook University in New York gleaned the first hints of the colony’s existence in 2014 by studying satellite images that revealed pixels of guano stains large enough to be seen from space. That suggested the presence of an unusually large number of penguins in an area where none had been suspected.
Not until scientists from Woods Hole Oceanographic Institution in Massachusetts, Louisiana State University and Oxford University visited the isolated islands a year later and started counting the penguins, however, did they realise the sheer size of the natural bird sanctuary they had discovered. On Friday, 2 March, they published their formal count in the journal Scientific Reports: The remote rocky islands were home to a “super-colony” of 751,527 breeding pairs of Adélie penguins—the largest colony in the entire Antarctic Peninsula. “When we first got these pixels of guano, I thought it might be a false alarm,” said Dr Lynch. “It wasn’t. We had massive penguin colonies that had not been known to exist.” The penguins’ nest on a tiny cluster on islands at the northern tip of the Antarctic Peninsula. An impassable barrier of sea ice typically isolates the nesting areas from fishing fleets intent on harvesting the krill on which the sprightly black and white birds depend. “It is called the Danger Islands because the area is so socked in with sea ice that it is very difficult to get a ship through,” even in summer, Dr Lynch said.
The expedition was funded by the Dalio Foundation, the family philanthropy founded by hedge-fund manager Raymond Dalio, which says it has so far given grants totalling $1.32 billion to a variety of causes, including ocean exploration. The team counted thousands of penguins by hand but also used a modified commercial drone to systematically image the entire nesting area. They counted penguins in the drone imagery using neural network software developed by Hanumant Singh at Northeastern University in Boston. Dr Lynch and her colleagues calculate that the entire Adélie penguin population in Antarctica now numbers more than 4.5 million breeding pairs—about 1.5 million more pairs than known 20 years ago. When they examined old aerial photographs of the region taken in 1957, they found evidence that the penguins were already in residence on the islands. “All the evidence suggests that population there has been stable since the late 1950s,” Dr Lynch said.
Credit: Robert Lee Hozt for The Wall Street Journal, 2 March 2018.