Penguins are among the most common birds in Antarctica.

Of all the Antarctic penguin species, only two – the Adélie and Emperor are known to breed along the shorelines and islands that surround the entire continent.

A new study led by researchers from the Woods Hole Oceanographic Institution outlines the discovery of a previously unknown “supercolony” of more than 1.5 million Adélie penguins living on the Danger islands, off the northernmost tip of the Antarctic Peninsula.

Some scientists had thought that the number of this penguin species had been steadily declining over the past forty years.

The researchers think that among the reasons the penguin supercolonies have gone unnoticed for so long may due the remoteness of the Danger Islands and the hazardous waters that surround them.

The study was published in a recent edition of the journal Scientific Reports.