Scientific name: Pygoscelis adeliae
Adélie penguins were discovered in 1840 by scientists on the French Antarctic expedition led by explorer Jules Dumont d’Urville. d’Urville named Adélie Land, in southern Antarctica, after his wife, Adéle. Scientists Hombron and Jacquinot also attributed this name to the species.
The Adélie is a medium sized penguin, weighing 3–6 kg and standing 70 cm tall. They are distinguished by the white ring surrounding the eye. Males and females are of similar size and difficult to tell apart.
Like all penguins, Adélies are excellent swimmers. In fact, some have been recorded swimming as far as 300 km (150 km each way) to forage food for their chicks. Adélies are not just good at swimming. They are very determined and successful long distance walkers, even though their short legs restrict them to a waddling gait on land. Their walking speed on ice averages 2.5 km/h and swimming speed from 4–8 km/h.
Distribution and abundance
Adélie penguins are one of only five species of penguins that live on the Antarctic continent (Adélie, emperor, gentoo, chinstrap and macaroni penguins). They are closely related to the gentoo (Pygoscelis papua) and the chinstrap (Pygoscelis antarctica) penguins.
Adélie penguins breed around the entire coast and small islands of Antarctica, in places where there is exposed rock. More than 80,000 pairs of Adélie penguins breed annually along the 40 km of Antarctic coast near Mawson station. Scientists at the Australian Antarctic Division study the Adélie penguin colony on Béchervaise Island, near Mawson as part of a long term ecosystem monitoring program. This colony consists of only 1800 breeding pairs, and is one of the smaller Adélie colonies.
Scientists know much more about the behaviour of Adélies in the warmer months, because they breed on land between October and February. Less is known about their behaviour in winter because they spend the winter at sea, amidst the pack ice. Scientists are tracking their routes so they can find out exactly where the Adélies go on their long sea journeys. So far, scientists know that these penguins can swim more than 1200 km away from their breeding site.
Conservation status: near threatened
Adélie penguins build nests out of the pebbles they find on dry land during spring. They choose a sloping site so that when snow melts, the water runs away from the nest. The nest must also be close to open water so the Adélies can eat.
Feeding is a problem in early spring when the pack ice has not yet broken up. They may have to walk 50 km or more over the ice to reach the sea before feeding. The penguins always return to the same nest and the same mate, if they can.
By mid-November there are two eggs in the nest. Both parents take turns to incubate the eggs, while the other goes to sea to feed. When the birds are not incubating the eggs, females spend 15–20 days at sea, while the males spend 10–12 days at sea regaining the weight lost during courtship. Once chicks hatch in December the parents alternate guard and feeding duties, they swap over every couple of days. The adult birds catch fish, krill and other small crustaceans, which they regurgitate for their chicks. The chicks on Béchervaise Island have been shown to grow by 80 grams per day.
In January, when chicks are three weeks old, they are big enough to be left alone. This allows both parents to simultaneously collect food for them. When the parents are away the chicks group together for protection and warmth.
In February the chicks replace their down with adult feathers and they are then ready to go to sea. At this stage the chicks are 7–9 weeks of age. Once they depart most chicks will not return to the breeding colony until they are 3–5 years of age and capable of breeding. Adélie penguins have a life expectancy of 10–20 years.
Diet and feeding
An Adélie penguin’s diet differs according to the location where food is captured. Local meals (those within 20 km of the colony) consist mostly of fish, amphipods and ‘crystal krill’ (Euphausia crystallorophias), while offshore meals consist of mainly ‘Antarctic krill’ (Euphausia superba). Meal sizes range from about 300–650 g depending on the size of the chicks.
Breeding adults travel between 5–120 km offshore to catch food for their chicks. Feeding trips range from 5–72 hours in duration.
Adélie penguins are capable of diving to depths of up to 175 m but usually feed within the upper 70 m of the water column.
Adélie satellite tracking
Scientists have attached satellite transmitters to selected Adélies so they can track their movements when out at sea feeding. The transmitters send signals to an orbiting satellite which relays the signals to the Australian Antarctic Division at Kingston, Tasmania. The sea routes of the penguins can then be mapped. Scientists often use dive depth recorders as well to determine how deep the penguins dive to catch their prey. The record dive for an Adélie is an amazing 175 metres.
Automated Penguin Monitoring System
Australian scientists have revolutionised the gathering of data from penguins. Before the new method was in place, scientists had to handle penguins repeatedly to obtain the information they wanted. Now the Automated Penguin Monitoring System automatically weighs, identifies and determines the direction of penguins as they walk across a weighing platform which has been placed between their breeding colony and the sea.
To identify each bird, scientists use a tiny electronic tag which they implant under the skin of the penguins. As the birds step onto the platform, their tag activates the system. Readings can then be obtained of how long each bird has been away foraging and how much food the bird gives to its chick. The weighing of penguins is important, as scientists can then tell how much krill and fish they are eating and delivering to their chicks.