Millions More Adelie Penguins Inhabit Antarctica Than Previously Estimated
Scientists studying Adélie penguins have found that their previous population estimates were off — by nearly 3.6 million individuals! So, how did this miscalculation occur?
Scientists at the University of Adelaide have now put the number of Adélie penguins at almost six million, significantly higher than previous counts.
The Adélie penguin is the smallest species of penguin in Antarctica. It is also the most widespread — and a key species in the Antarctic food web. Adélie penguins prey on small fish and krill, but they serve as prey for larger animals such as leopard seals and killer whales.
The penguins are rated by international wildlife groups as being of “least concern” for conservation. That’s not to say that they’re completely free of danger, though.
With increasing global temperatures, researchers have noticed that Adélie penguin populations have fallen. The WWF estimates that decrease to be in excess of “65 percent in the past 25 years.”
While other penguin species can stand somewhat warmer temperatures, the Adélie aren’t well suited to changes in their environments, like less ice cover and altered fish behavior that can affect how they feed.
As a result, the discovery of an unexpectedly robust population is great news.
But why the large jump in numbers?
Well, the first thing to know is that Adélie penguins haven’t been multiplying with abandon. Rather, the increase in population comes down to scientists using a more intricate method of counting.
Previous estimates relied on aerial surveys of breeding pairs. Counting breeding birds tends to be a good measure of how well a species is doing, but it can’t give an accurate picture of the total population. Normally during breeding season, most birds would be on land, but not all species — or individuals — adhere to the pattern.
To take a closer look, researchers used a combination of aerial and ground surveys, as well as automated camera images. This gave them a more complete picture of the birds’ activity and a better means of capturing the penguins who were always on the move. The result? A much bigger population than they had expected.
Ecologist Dr. Louise Emmerson characterized these findings as important because they improve our understanding of Adélie penguin society and its needs.
Non-breeding birds are harder to count because they are out foraging at sea, rather than nesting in colonies on land. However, our study in East Antarctica, has shown that non-breeding Adelie penguins may be as, or more, abundant than the breeders. These birds are an important reservoir of future breeders and estimating their numbers ensures we better understand the entire population’s foraging needs.
More penguins is surely better, right?
While a larger penguin population is encouraging in terms of conservation efforts, the scientists in this study raise a few concerns.
Ecologists already knew that the penguins were traveling considerable distances in order to find their food — sometimes many miles. This research suggests that, with a bigger population than previously thought, there’s more chance that the penguins will come into contact with humans. And as we’ve observed in other habitats, animals and people do not tend to mix well.
Another issue involves the penguins’ breeding grounds. As the population increases and climate change alters the landscape of the Antarctic, protecting those valuable habitats could become even more challenging.
Lastly, higher numbers also means greater pressure on the species that penguins feed on, namely fish and krill.
Luckily, with these more accurate numbers, researchers will now be attuned to potential hazards. In the meantime, scientists are working to understand how our changing climate will affect the region and impact key species like the Adélie penguins — and, crucially, how we can help them survive.
Photo credit: Thinkstock.