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A never-before-seen colony of emperor penguins — one of only 66 known to exist — has been spotted by chance in satellite photos of West Antarctica that clearly show their guano, or droppings, staining the ice.
The colony is estimated to be home to about 1,000 adult birds in 500 pairs with their young, making them relatively small for an emperor penguin (Aptenodytes forsteri) hotbed. But it is an important addition to what is known about the species.
Peter Fretwell (opens in new tab), a geospatial information officer with the British Antarctic Survey (BAS), spotted the colony in December; However, the announcement was postponed to coincide with Penguin Awareness Day, which occurs on January 20th each year.
Fretwell told Live Science that he viewed the sea ice loss in photographs of the two from the European Space Agency Copernicus Sentinel-2 satellites (opens in new tab) when he spotted the distinctive signs of an emperor penguin colony. “I could see what appeared to be a very small brown speck on the ice,” he said.
Related: Penguins gave up flight to swim more than 60 million years ago. Here’s how.
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Higher resolution photos of the same area taken in October by the Maxar WorldView-3 satellite (opens in new tab)which can image objects as small as 30 centimeters in diameter, confirmed the presence of the breeding colony near Verleger Point in West Antarctica, Fretwell said.
Because the penguins’ guano accumulates and turns ice and snow a deep brown, it’s much easier to see from a distance than the emperor penguins themselves. But the high-resolution images also show individual emperor penguins — represented as tiny dots — and the population estimate is based on those, he said fretwell
Seabirds by Satellite
Emperor penguin colonies are often remote and difficult to study, but BAS scientists have spotted several in satellite photos of the Antarctic coast over the past 15 years. Recent satellite research has even suggested they might exist 20% more emperor penguins in Antarctica than previously thought.
Emperor penguins breed exclusively on packed sea ice. However, this dependence on sea ice also makes penguins vulnerable to their loss in a warming climate; and West Antarctica is already badly affected.
“Last year in Antarctica we had the lowest sea ice extent ever, and this year it’s even worse for two straight years,” Fretwell said. “It is estimated that we will likely lose at least 80% of emperor penguin colonies before the end of the century.”
Because of this threat climate changeEmperors are now listed as an endangered species under the US Endangered Species Act.
Stately penguins
Emperor penguins are the largest and heaviest of all penguins. They typically reach a height of up to 100 cm and a weight of up to 45 kg. They get their name from their dramatic black, white, and yellow plumage.
Emperors spend most of the Antarctic summer diving for fish, crustaceans, and krill. They breed on the surface of packed sea ice during the dark winter months, sometimes more than 50 kilometers from the open ocean, and where temperatures can plummet to minus 76 degrees Fahrenheit (minus 60 degrees Celsius).
Fretwell recently visited Antarctica to drone observe another large colony of emperor penguins from the air and to confirm numerical estimates of penguin breeding colonies, which can only be seen in satellite photos.
And while he was close enough to smell the penguin poop, it wasn’t that bad, he said.
Because emperor penguin colonies reside on sea ice, much of the guano is frozen and odorless — unlike the penguin colonies that breed between rocks, where the odor can be intense. “The emperors are more portly and don’t smell like other penguins,” he said.
