by Mike King
Of the 18 penguin species currently recognized by science, none are quite as mischievous as the Adelie penguin (Pygoscelis adeliae). These birds live in large colonies along the rocky banks of Antarctica. Adelies, like most penguins, are very dedicated parents. They build small nests out of stones to protect their chicks. Many of these parents even steal stones from other nests in order to protect their own!
Although Adelie penguins fit the typical morphological description of most penguins (awkward, round, and stubby-legged), they are capable of accomplishing incredible physical feats. They migrate up to 31 miles every spring on foot! Like all penguins, they are also capable swimmers. Adelie penguin chicks are able to swim on their own at the young age of 9 weeks.
The diet of the Adelie is quite unusual for that of a penguin. Most penguins feed almost exclusively on fish, but the vast majority of the Adelie’s diet is made up of tiny marine organisms called krill. Krill are small, shrimp-like crustaceans that provide a basic food source for countless marine creatures. Because of the constant threat of predation, krill are highly adapted swimmers. Adelie penguins must swim with incredible athleticism and stealth in order to catch their food and survive. In a video released by penguin researcher Yuuki Watanabe in 2013, viewers are able to see from a penguin’s point-of-view just how chaotic these underwater chases can be. It is not difficult to appreciate the amazing balance of nature put on display by the competing survival abilities of both species. This ecological balance, however, can only withstand a certain amount of strain before it tips over.
Often times, animal populations are threatened by humans due to overharvesting of their prey. In the case of Adelie penguins, however, an overabundance of their prey may be indicative of a greater ecological issue. According to the IUCN Redlist, Adelie penguin populations have increased at a rate of about 2% per year since the mid 1990’s. This may sound like great news, but some researchers disagree. According to papers released by Fraser et. al. and Taylor et. al., the increase in Adelie penguin populations may actually be linked to climate change. Fraser et. al. found that the loss of sea ice on the Antarctic continent has led to greater numbers of krill, thus increasing the survivability of Adelie penguins. Therefore, this massive increase in penguin population indicates just how much climate change can affect an ecosystem. More penguins may sound like a good thing, but in this case they may begin to outcompete other species and begin slowly hunting the krill to drastically low levels. Of course, this is only one issue melting sea ice can cause.
There has been growing concerns in the scientific community about climate change since the 1960s. Governments around the globe started to take action in the 1980s through legislative procedures. Many scientific studies have predicted massive extinction rates, flooding cities, the loss of pollinators (and also therefore fruit) will all be likely events if climate change is to continue on its current course. With the knowledge of how the Adelie penguin population corresponds to climate change, scientists can begin to monitor the progress being made by rising ocean temperatures in a much simpler way than in the past. Adelie penguins may now be used as an “indicator species”—a living organism whose presence and abundance can be used to tell us things about an ecosystem. The concept is not a new one; scientists have used indicator species such as marine invertebrates in order to determine the overall health of an ecosystem. Basically, we can monitor the population of Adelie penguins in Antarctica, and use that information to determine how much sea ice was lost since the last population assessment.
Listed as “Least Concern” by the IUCN Redlist, Adelie penguins have not taken center stage in any major conservation movements. However, with the information we now possess, we will be able to conduct more studies on Adelie penguin populations and their effects on krill populations to gain a better understanding of how rapidly climate change is melting sea ice in Antarctica. This small, stone-stealing bird is much more than a cute video to be laughed at. It is a looking glass into the health of our Southern Ocean, and may shed light on how quickly we must act to protect it.
Next stop — Northern Rockhoppers Penguins!