Antarctica: Scientists find 1.5 million penguins

Scientists have found more than 750,000 breeding pairs of Adelie penguins in the previously unknown colony at Antarctica's Danger Islands, according to a study published in Scientific Reports on Friday.

The hotspot is located in the remote, rocky archipelago of the nine Danger Islands, off the tip of the Antarctica Peninsula that points towards the South American continent. The islands are covered by heavy sea ice for most of the year, and most of them are visited by less than one ship annually, explaining how the colony remained unnoticed for so long.

"It is certainly surprising and it has real consequences for how we manage this region," study co-author Heather Lynch of Stony Brook University told the AFP news agency.

Sheltered from global warming?

The discovery of 1.5 million penguins comes amid a prolonged decline of Adelie populations in other parts of the peninsula. In recent decades, the number of penguins in the region dropped by some 70 percent due to melting ice. The Danger Islands, however, seem to be less affected.

"Not only do the Danger Islands hold the largest population of Adelie penguins on the Antarctic Peninsula, they also appear to have not suffered the population declines found along the western side of Antarctic Peninsula that are associated with recent climate change," said Michael Polito from Louisiana State University.

Following the guano

Researchers were first alerted to the possibility of a large penguin colony while reviewing satellite images provided by NASA and the US Geological Survey. The data suggested large guano (bird excrement) stains on the islands, indicating hundreds of thousands of birds. Initially, researcher Heather Lynch thought it "was a mistake."

Upon review, however, the team decided to set up an expedition to the islands. The researchers arrived at the site in December 2015 to find one of the largest Adelie colonies in the world.

Read more: Climate change pushing Antarctica's king penguins to brink of extinction

Drone for a 'bird census'

The group started by counting the birds by hand. Soon, however, they deployed a modified commercial drone to photograph the island from above. The drone uses a special imaging and navigation system, developed by Professor Hanumant Singh from Northeastern University.

"The drone lets you fly in a grid over the island, taking pictures once per second. You can then stitch them together into a huge collage that shows the entire landmass in 2D and 3D," he said in the article published by the Woods Hole Oceanographic Institution.

The scientists also used neural network software to conduct a "bird census" at the newly discovered colony.

Islands need protection

In the future, Antarctic conservations will likely use the data as an argument for curbing human activity near Danger Islands.

"The most important implication of this work is related to the design of Marine Protected Areas in the region," said Lynch. "Now that we know this tiny island group is so important, it can be considered for further protection from fishing."