It’s the March of the penguins.

On Friday, researchers published an exciting new discovery in the journal Scientific Reports: Antarctica’s Danger Islands hosted a massive community of Adélie penguins.

At least 751,527 pairs to be exact.

Like trackers in the wilderness, researchers used a time-tested way to identify the birds: they noticed their poop.

Satellite images revealed a giant mound of excrement, known as guano, on the island, and the discovery tipped scientists off to the humongous cluster of penguins nearby.

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Antarctic Penguin hotspot discovery fuels need for marine reserve: Scientists have discovered a thriving colony of more than 750,000 Adélie penguins, where the impacts of #climatechange have not yet been felt and there is little human activity: https://t.co/4ODWEcaCPopic.twitter.com/3n0smlmV0X

— Oxford University (@UniofOxford) March 2, 2018

Beginning in December 2015, a team of researchers visited the island and used drones to photograph and count the island inhabitants.

The population of more than 1.5 million penguins includes the third and fourth largest Adélie penguin colonies in the world, the scientists report. And the amount of penguins shocked several scientists on the team, including Heather Lynch, a researcher from Stony Brook University in New York.

"The sheer size of what we were looking at took our breath away," Lynch told BBC News. "We thought, 'Wow. If what we're seeing is true, these are going to be some of the largest Adélie penguin colonies in the world, and it's going to be well worth our while sending in an expedition to count them properly.’"

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Scientists have worried about declining Adélie penguin populations elsewhere in the region but said the discovery reveals that the species can still thrive in western Antarctica — even if scientists can’t find them.

"It's a classic case of finding something where no-one really looked. The Danger Islands are hard to reach, so people didn't really try that hard," research scientist Tom Hart told BBC News.

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The Danger Islands continue to provide a safe place for Adélie penguins to fish for krill, waddle home, and feed their chicks because they are secluded and give the penguins access to a sufficient food supply. But elsewhere, in Antarctica and around the Arctic, melting sea ice places penguins and other animals at risk of starvation, death, and extinction.

Polar bears need sheets of ice to hunt for seals. Without it, they cannot travel out to sea in search of food and end up starving to death. In 2016, 150,000 other Adélie penguins died when a giant iceberg crashed into their coastal colony and cut them off from the sea, which they depend on for food.

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Without concerted efforts to reduce climate change, penguins, polar bears, and other species will perish.

"This exciting discovery shows us just how much more there still is to learn about this amazing and iconic species of the ice," Rod Downie, the head of polar programs at the World Wildlife Federation, told Business Insider. "But it also reinforces the urgency to protect the waters off the coast of Antarctica to safeguard Adélie penguins from the dual threats of overfishing and climate change."