Elise Meredith Jimison

Introducing the Adélie Penguin

Adelie penguins are the most widespread of the living penguin species, and quite possibly the most abundant. During the Antarctic summer, they return to large, noisy rookeries on nearly every ice-free coastline of mainland Antarctica as well as outlying islands as far north as the South Sandwich Islands. About 3.8 million breeding pairs lay two eggs each and incubate them constantly, with males and females taking turns on the nest. It’s an exhausting task, and once the chicks are large enough to stand on their own, both parents must hunt constantly both to feed the growing chicks and to recover their own body weight.

Young Adélies huddle in groups to protect each other against cold and predators. Over their first summer they exchange their first coat of light-gray down feathers for a second, darker coat of down; then molt again into juvenile plumage featuring solid black feathers on the head, back, and tail and solid white feathers on the belly and throat. They’re capable of swimming and foraging on their own from this point, and will follow the adult Adelie penguins gradually north and out to sea in search of holes in the ice through which to hunt.

Adélie penguins absolutely refuse to nest on ice, so they spend their summers clustered together on carefully-selected patches of coast where the sun direction and prevailing wind keep a rocky beach swept clear of snow. As the winter pack ice begins to form, colonies begin to migrate northward onto the floating landscape. The penguins don’t need open water to fish, but they need to be sure of openings in the pack ice in order to access food and escape predators. They also seem to need some visible sunlight each day, so they usually migrate at least to the 70th parallel and can travel as far north as the 60th. Occasionally, a few solitary adventurers find their way to New Zealand or Tasmania. They feast on krill and other marine invertebrates, small schooling fish, and–surprisingly–jellyfish.

Upon their return to the breeding grounds, the Adelies all sport their signature white eye ring, pink-and gray beak, and black chin. Their adult tail feathers are stiff and bristly, enough that they can be used for balance on uneven terrain. The adults are also recognizable for their fearlessness and curiosity. They charm tourists and veteran researchers by running to examine strangers, rummaging through unfamiliar objects with gusto, and meeting threats with a raised crest and courageous barking and growling. The combination of their personable demeanor, unmistakable appearance, and ubiquitous presence at the edges of the pack ice have made them a constant feature in the journals of explorers and scientists since they were first officially described in 1840. One survivor of the British expedition to the South Pole in 1910 wrote of Adélie penguins, “because he is quaint in all that he does, but still more because he is fighting against bigger odds than any other bird, and fighting always with the most gallant pluck, he comes to be considered as something apart from the ordinary bird”.

Adéle, the Adélie Coast, and the Voyage of the Astrolabe and Zélée

The first published scientific description of the Adélie penguin came from two French naval surgeons, Honoré Jaquinot and Jaques Bernard Hombron, who accompanied Capitaine de Vaissaux Jules-Sébastien-César Dumont d’Urville on a four-year exploratory voyage commissioned by the French government to the Straits of Magellan and eventually up to the actual coast of Antarctica from 1837 to 1840. One goal of the voyage was to out-navigate British captain James Weddell by exploring further south than his furthest recorded position of 74 degrees 15 minutes South, another was to attempt to locate the magnetic South Pole (believed to be off the coast of Antarctica directly South of India and Indonesia).

Neither of Dumont d’Urville’s ships were well-equipped for navigation within the antarctic pack ice, so the Astrolabe and the Zélée had nearly circled the continent by the time the summer weather and intense westward ocean currents gave them the opportunity to turn South across the 72nd parallel. When the expedition finally sighted the coast of continental Antarctica, they were just South of what is now Tasmania. Dumont d’Urville claimed the extent of the previously-unexplored coastline for France, and named it Terre Adélie after his wife, Adéle. Meanwhile, Hombron and Jaquinot collected biological specimens from the pack ice, naming the large black-and-white birds they discovered Adélie penguins after the new French territory in which they were found.

Terre Adélie (Adélie Land or the Adélie Coast for all the English speakers here) is still on the map, with a French presidential decree officially defining it in 1938 as “the islands and territories situated south of the 60-degree parallel of south latitude and between the 136-degree and 142-degree meridians of longitude east of Greenwich,” which amounts to about a six-degree pie wedge of Antarctica, or 3.1% of the continent, or 432,000 square kilometers of mostly glacier. As it happens, the South magnetic pole is currently within that territorial claim, as is a permanent research station named for CdV. Dumont d’Urville. Of course, the Adélie penguins don’t know and don’t care, so they take the liberty of forming thriving colonies on all the other coasts as well.

Adélies, Ice, and Climate

The wide geographic range of Adélie penguins make them one of Antarctica’s most accessible species to study, and their dependence on floating pack ice for their migrations makes them an incredibly useful source of ecological data about Antarctica, its dense accumulations of glacial ice, and especially the mysterious, cold sea that surrounds it.

Recent research suggests that the distribution of Adélie penguin rookeries may be one of the more practical indicators of shifts in the global climate. Permanent ice accumulations in the Arctic and Antarctic account for enough of the world’s water that measuring the thickness of glacial and sea ice can help to predict changes to the sea level, the ocean’s temperature, and even the weather–often years in advance. It’s of less use in predicting the behavior of animal species, because living things adapt based on an incredibly complex web of needs and opportunities. At the moment, Adélie penguins seem to be ok with the world’s weather, but growth and decline in individual Adélie populations are often drastic, and seem caused by contrary events. Within the last 25 years, colonies of Adélie penguins on the Antarctic Peninsula (the finger of land that nearly connects Antarctica with South America) have declined by 62%, a decline that seems to correlate with lower krill populations in the increasingly warm and iceless Weddell Sea. A large colony near Mawson Station in East Antarctica has experienced a 42% decline since 2012, which researchers attribute to a sustained period of surplus sea ice that made it difficult for nesting adults to find enough prey to feed their hungry nestlings.

An ambitious satellite survey of nesting sites all over the continent estimates that populations farther south suggests that the total number of Adélies is much higher than previous estimates simply due to the difficulty surveying remote colonies in person. Researchers Matthew Schwaller, Colin Southwell, and Louise Emerson feel that the most promising results of their new surveying method is the possibility of gathering accurate data about populations of penguins on a whole-continent scale. With more information available from different parts of the continent, scientists hope to use Adélie behavior to predict how other species may respond to changes in their environment. It may even be possible to avert disaster for more fragile species based on what we find out. However, even the adaptable Adélies may surprise us. If receding sea ice leaves them without a route to migrate with the sunlight, we may find out too late why they travel so far north in the winter. If they continue to concentrate at the southernmost part of their range, they may edge out other species. This combination of accessible data and endless possible outcomes has lead researcher David Ainley to dub them “the bellwethers of climate change.”

Sitting On History

The last seventy years of global and regional climate change aren’t the first time the Adélie penguins have had data to share about man-made changes to their ocean home. According to research published in 2007, the Adélies have spent the last two centuries literally sitting on one of the origin stories of the ocean ecosystem we see today. Ecologists have hypothesized for decades that the overhunting and near-extinction of Minke and humpback whales and krill-eating seals between 1700 and 1950 must have changed the Antarctic landscape beyond recognition. Specifically, it seemed reasonable to believe that thousands of tons of krill now survive and multiply beneath the ice that would once have been gobbled up by abundant populations of gigantic marine mammals. If true, a “krill surplus” beginning shortly before the time of the earliest polar explorers would help piece together the behaviors and distributions of many of the species we’re currently able to study, and shed some light on the extinction of others.

However, it’s hard to estimate the number of krill available based on historical records–while many captains recorded the numbers of baleen whales and fur seals they saw, nobody thought to count the tiny invertebrates until it was too late. In 1999, marine biologist Stephen Emslie and paleontologist William Patterson turned to the layers and layers of perfectly preserved, discarded eggshells that carpet the largest Adélie penguin colonies for possible evidence. Since any stable compounds in the chemistry of the shells would have been preserved by the desert conditions and freezing cold, their chemical composition should serve as a record of what the penguins had eaten for as long as the colony had existed. After carefully matching the age of their samples with dated and labeled specimens from museums and correlating them with samples from all around Antarctica, the researchers measured the levels of stable Nitrogen and Carbon isotopes preserved in discarded Adélie penguin eggshells. As predicted, specimens from all around Antarctica demonstrated an abrupt change in composition consistent with a change in diet from mostly vertebrates to mostly krill in shells dated to the first half of the 1800s.

With help from thousands of fearless, flightless penguins, we’re beginning to understand a little of what goes on in the remotest places on earth, and how our choices here in the temperate part of the world may be changing things for wildlife in Antarctica and for ourselves. Ongoing research looks to polar ecosystems and indicator species like the Adélies to model everything from solar storms to ozone layer restoration to nutrient return from the ocean to farmland in the American midwest. It’s not a death-defying voyage in a wooden-hulled ship, but it’s still discovery.

Adventure to the Adélies!

If you’re like me and live in the northern hemisphere, you’re unlikely to ever attract an Adélie penguin to your bird feeder. However, we don’t live in the age of wooden sailing ships and whaling voyages anymore, so packing your warmest coat and heading out to see some Adélie penguins in their own home could be your vacation of a lifetime! Jonny and I are both avid armchair travelers, so we decided we’d finish this post with each of our picks for a dream Adélie-spotting vacation.

Jonny’s pick: Christmas in Antarctica, out of Ushuaia, Chile with Polar Latitudes. The Antarctic Peninsula has Gentoo and Chinstrap Penguns too, December is a great time to see penguin chicks with their parents, and it would be the whitest white Christmas ever!

Elise’s pick: Aurora Expedition’s Ross Sea Odyssey cruise out of Dunedin, New Zealand. Definitely super expensive and time-consuming, but this is armchair travel after all! Almost a whole month of the Victoria Land coast and the Ross Ice Shelf to see Adélies fishing between the pack ice, plus visits to the camps of some of the most famous early polar expeditions. While we’re there, let’s definitely tack on an extra day in New Zealand to try to see some Yellow-eyed penguins and Little penguins as well!

If you’ve had the chance to hang out with an Adélie penguin, in Antarctica or somewhere else, please write a comment and tell us all what it was like! If not, feel free to share your dream itinerary so we can all daydream this voyage together. And of course, if you do make it down to see them in their native habitat, please make sure you say hi from me and the rest the Birds in Berets community!