A previously undiscovered colony of emperor penguins, one of only 66 known to exist, was accidentally discovered in satellite photographs of West Antarctica. The colony can be identified by the visible stains of droppings, known as guano, on the ice.
The colony is believed to have a population of around 1,000 adult birds and 500 breeding pairs with their offspring. Although the colony is relatively small compared to other emperor penguin breeding sites, it is still an important discovery for understanding the species.
In December, Peter Fretwell, an officer specializing in geographic information at the British Antarctic Survey, discovered a new emperor penguin colony while examining photographs of sea ice loss from the European Space Agency's Copernicus Sentinel-2 satellites. The discovery was not announced until January 20th, Penguin Awareness Day.
Poop Stains on Snow
Fretwell stated that he noticed a small brown stain on the ice that appeared to signify an emperor penguin colony. Fretwell also mentioned that higher-resolution images of the same location taken in October by the Maxar WorldView-3 satellite, which can capture objects as small as 30 centimeters, confirmed the colony's existence near West Antarctica's Verleger Point. The penguins' droppings (guano) create a distinct deep-brown stain on the ice and snow, making it easier to spot the colony from a distance.
The high-resolution images also enabled Fretwell to identify individual penguins as small dots, which aided in estimating the population of the colony. Emperor penguin colonies are known to be located in remote areas and are challenging to study. However, scientists from the British Antarctic Survey have been able to locate several colonies by analyzing satellite images of Antarctica's coastline over the past 15 years.
Recent satellite imagery research has even indicated that there may be around 20% more emperor penguins in Antarctica than previously thought. Emperor penguins only breed on sea ice, which makes them particularly susceptible to the loss of sea ice due to a warming climate, and the West Antarctica region has already been severely impacted.
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Largest and Heaviest Penguin
Fretwell stated in Live Science that last 2022 the team had the lowest ever sea ice extent in Antarctica, and this year is even worse, for two consecutive years. He added that it's estimated that they will probably lose a minimum of 80% of emperor penguin colonies before the end of the century. Due to this threat from climate change, Emperor penguins have now been considered a threatened species under the U.S. Endangered Species Act.
Emperor penguins are the largest and heaviest among all penguin species, typically growing up to 100 cm in height and weighing up to 45 kg. They are named for their striking black, white, and yellow plumage. Emperor penguins spend most of the Antarctic summer hunting for fish, crustaceans, and krill. They breed during the dark winter months on the surface of packed sea ice, sometimes located more than 50 km from the open ocean, in temperatures as low as -60°C.
Recently, Fretwell travelled to Antarctica to observe another large emperor penguin colony using aerial drones to confirm the numerical estimates of penguin breeding colonies only seen in satellite photographs. He said that even though he got close enough to smell the penguin droppings, it wasn't as bad as expected. Emperor penguin colonies are on sea ice, and much of the guano is frozen, which doesn't have any smell, unlike the colonies of penguins that breed among rocks, where the smell can be intense. Fretwell stated that emperors are more stately and not as smelly as other penguins.
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