Scientists studying guano (i.e., bird poop) distribution in satellite imagery have stumbled upon a stupendous discovery: a "secret" Adélie penguin kingdom previously unknown to researchers that contains 1.5 million birds, hidden on a remote Antarctic archipelago, reports BBC News.

The Danger Islands, so named because the first European explorers to come across them considered them a potential shipwreck hazard, are rarely visited, even by researchers. In turns out, those treacherous shores also make the islands a perfect hideaway for penguins.

"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," explained team-member Dr Tom Hart from Oxford University.

Researchers used NASA’s orbiting Landsat satellites and a specialized algorithm to find patches of guano, in an effort to more effectively study penguin population dynamics in the region. It didn't take long for them to realize that there was way more poop than their were penguins, at least according to population estimates from known colonies.

"The sheer size of what we were looking at took our breath away," said Dr Heather Lynch from Stony Brook University, New York. "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."

An expedition to the islands confirmed the existence of the mega-colony, which researchers then mapped out with drones. Sure enough, the penguin count ranks the colony as one of the largest in the world. And the good news is that the population here appears relatively stable compared to colonies on the decline in other regions of Antarctica, probably because of its geographic isolation.

Now that this penguin kingdom has been unveiled, however, researchers worry that some of the environmental impacts affecting other regions could inevitably jeopardize the safety of this colony too. They hope that the discovery will prompt new designations for the Danger Islands as Antarctic Specially Protected Areas (ASPAs) or Marine Protected Areas (MPAs).

“Given the large number of Adélie penguins breeding in the Danger Islands, and the likelihood that the northern Weddell Sea will remain suitable for Adélie penguins longer than the rest of the Antarctic Peninsula region, we suggest the Danger Islands should be strongly considered for further protection,” the team wrote in their paper, which was published in the journal Scientific Reports.

Some drone footage of this once-secret world can be seen here: