The number of Adélie penguins living in East Antarctica may be double what scientists previously thought.

Until this most recent study, scientists drew their estimates by counting breeding pairs. However, this means previous counts missed non-breeding penguins.

“Non-breeding birds are harder to count because they are out foraging at sea, rather than nesting in colonies on land,” Louise Emmerson, a seabird ecologist with the Australian Antarctic Division, says in a press release.

Using a combination of aerial and ground surveys, as well as automated camera images, researchers were able to collect more accurate population counts over several breeding seasons and revise their estimated totals.

Higher numbers are a cause for celebration and concern. Adélie penguin colonies span the