(Pygoscelis adeliae)
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ADELIE PENGUINS (Pygoscelis adeliae) |
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Adelie Penguins When you think of the traditional "tuxedoed" penguin the Adelie most closely fits the billing. They stand approximately 27" tall and are jet-black in color except for their abdomin and the underside of their flippers, which are white. Each eye is encircled by a thin white ring. Ungainly and comical to watch while they are on the surface, they can truly fly under the water. Ross Island has several Adelie Penquin colonies called "rookeries". Thousands of Adelies gather together to mate and build nests for their eggs.
Habitat & Ecology Anatomy
Mean Weight: 5.0 kg Ecology
Inhabits: Antartica, peninsula regions,islands Under the Water Among Antarctic scientists and explorers, the tale of the "cautious penguins" is legendary. During the breeding season, the tale goes, penguins crowd by the thousands on small strips of icy shoreline, waiting to see which penguin will be brave enough to explore the dark waters. The danger? Seals. Leopard seals to more exact. Adelie Penguins cluster together on the ice before jumping into the Antarctic waters. Leopard seals, it has been rumored, consider Adelie penguins to be their number one delicacy. The seals are known to wait in ambush under the surface of the water for any "foolhardy" Adelie to enter from the icy beach above. The leopard seal is renowned for its hunting prowess, while the Adelie penguin is famous for its overt cautiousness and intelligent escape tactics. But is this the whole story? Researcher Gordon S. Court set out to find the truth behind the tales. Leopard seals can grow up to eleven feet long and weigh 900 pounds -- females usually grow 10% larger than males. "Although penguin hunting is their most dramatic feeding activity," writes, Court, "it provides only a small part of the seals' varied diet." Stomach contents have shown that the seals' diet consists of 50% krill, 40% fish and squid, and up to 10% birds and other seals. As for the penguins, Court writes, "Although most reports about leopard seals and penguins stressed the hazards faced by birds when first entering the water, we found that penguins swimming toward shore when returning from foraging trips were at greatest risk. Only one in thirty chases involved a penguin that was leaving the ice edge." Speaking of a particular chase, Court wrote the following account: "For long suspenseful moments, the chase of one Adelie continued underwater; rapid changes in the direction of the bubbles indicated that the seal was in hot pursuit. Suddenly, the zigzag changed to a straight line, an all-out test of speed with both animals rising, arcing, and resubmerging in syncrony. An Adelie penguin on land is an ungainly thing, but in water, it moves like a salmon and, when traveling fast, clears the surface every few seconds to breathe. To see an eleven-foot-long leopard seal, weighing perhaps 800 pounds, match this performance, stroke for stroke, is spectacular. The chase lasted for some minutes, long enough for four scientists working in different parts of the penguin rookery to look out to sea and watch the Adelie successfully outdistance the seal." Source: Natural History, August 1996 (Gordon S. Court) Breeding Facts
Adelie penguins breed during the Antarctic summer from December to February. Adelie penguins are highly gregarious both on breeding stations and at sea. They gather in large rookeries where they build rock nexts and typically lay two eggs. They usually breed on broad flat protected areas above the beach up to 200 meters high. To reach most colonies early in the season, Adelies must travel 30-100 km over the ice. Some colonies may be 300 km from open water in October. Early in the season the nest and eggs may be nearly submerged by melting ice, and incubating birds may occasionally be buried in melting snow. Unlike Emperor penguings, Adelie penguins do not balance their eggs on their feet to keep them warm. Instead, they have a brood patch on their stomach which is an area of bare skin without feathers. This brood patch keeps the eggs warm during the length of incubation - about 33 days. The parent will lie down on top of the eggs until they hatch, and will even keep the chicks warm the same way until they are about one week old.
In order to reduce energy demands during incubation in cold weather further, Adelie and Emperor penguins can
lower body temperature at least 4 degrees Celcius below normal resting temperature. Adelie penguins that breed
on the mainland are able to complete their breeding cycles before sea ice disperses. They release their chicks
before they are fully grown.
Audio files of Adelie penguins
References: Antarctic Researchers Take Close Look at the Penguin-Seal "Relationship" Science and the Environment - Voyage Publishing 1996
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