Satellite images of pinkish fecal trails in an Antarctic island show whole new colonies of Adélie penguins, allowing scientists to track this endangered species.

Adélie penguins eat shrimp-like krill, which gives their guano or feces the pinkish color. When they defecate on the ground, the stain leaves the same smudgy and vibrant color on their body and the snow. Clusters of reddish and brownish circles can be seen on areas that are closer to the ocean in Cuverville Island.

Tracking The Penguins

The guano trails are particularly helpful for the scientists to determine the potential number of Adélie penguins that live in one of the most remote places in the planet.

"We don't see individual penguins in the satellite imagery," said Heather Lynch, a Professor of Ecology at Stony Brook University in New York. "And we can work out from the area of the guano stains how many penguins must have occupied that site."

In 2015, Lynch and her group used drone imagery to count Adélie penguins in the Danger Islands, which they estimated to be 750,000 pairs or 1.5 million individual penguins. These birds are crucial indicator of the health of the Antarctica since they live and breed on both icy and rocky surfaces.

Endangered Species

Ecologist Casey Youngflesh, who works on the penguin guanos for analysis, said that changes in its color are associated with changes on the birds' diet over time. Its main food source, krill, is also in demand for the manufacture of fish oil supplements.

The global population of Adélie penguins is now estimated at 4 million pairs, which has grown double its number over the last four decades. However, their number in the Western Antarctic Peninsula has decreased substantially in the last few years due to climate change.

All of the species of penguins in the Antarctica, including the Adélie, now face habitat loss.

"Now that we know how important this area is for penguin abundance, we can better move forward designing Marine Protected Areas in the region and managing the Antarctic krill fishery," Lynch said.

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