Of Ponies and Penguins
Adelies are one of only two types of penguins that live on the Antarctic mainland. They are named after the wife of one of the early (1830s) Antarctic explorers, Frenchman Dumont d’Urville. With the adults rarely weighing in at more than 11 pounds and being only around 18" tall, Adelies are one of the smaller penguins. They migrate to colonies in October, returning year after year if possible to their birth grounds. The Adelies lay their eggs on rocky, ice-free beaches in November, and chicks hatch in December. At the time of our visit, the chicks were around six to seven weeks old.
In order to protect the penguins, environmental laws prevent people except penguin researchers from going into the colony. But Penney, our helicopter pilot Paul Murphy, and myself were still able to observe the penguins from a distance and capture some of the action with a zoom-in camera lens. David Ainley who’s been studying the Adelies since the late 1960s provided some insight into what is going on at the colony. Check out these photos!
Click on the photos to see a larger view.
Chicks and parents identify each other both through the position of the nest and through calls, explains Ainley. Calling to its chick is what the adult penguin in this photo with its neck stretched out is doing. Also in this photo are two chicks chasing some adults in the hopes of getting food. The chasing serves to weed out weak and unhealthy chicks. In addition, it helps parents distribute food more evenly says Ainley, because a chick that is hungrier will likely chase more vigorously than a chick that is less hungry. The enthusiastic chases of the young penguins were pretty comical to watch and sometimes we saw the chicks apparently trip and fall down in their excitement. But they just got right back up and kept going!
The chicks in the lower left and upper right of this photo have caught up with a parent, and the adults are feeding the chicks. An adult does this by regurgitating food into the chick’s gaping bill. The food consists mainly of fish and krill that the adults have consumed while at sea.
Again, the two chicks in the middle of the photo are chasing some adults.
When the chicks are born, one parent stays with them at all times to keep them warm and prevent skuas, which are large gull-like birds, from stealing and eating the chicks. The other parent goes out to sea to find food. When the chicks reach three to four weeks of age though, this guard phase ends and what’s known as a crèche phase begins. The chicks are growing rapidly and require more food. Now both parents must go to sea at the same time and hunt. The unattended chicks gather into groups or crèches, like the one in this photo, for protection against skuas and the elements.
If you look closely, you can see that some of the chicks have started to molt or shed their brown/charcoal down feathers to reveal the sleek, black and white waterproof feathers of an adult. They need to molt completely before they will be ready to swim and dive Ainley notes.
Extra sea ice has been making life rough for the Cape Royds Adelies. Giant icebergs calved off the Ross Ice Shelf in 2000, and the icebergs have prevented winds from blowing out the sea ice. This has meant that parents have had to walk some 80 km one way to open water and has reduced the frequency with which parents have been able to feed their young.
A few years ago there were 4000 pairs of Adelies breeding at Cape Royds, says Ainley. This year that number has been cut to 2400 pairs. Sometimes ice breaker ships unintentionally give the Adelies a brief respite though. These ships are specially equipped to break through sea ice and create paths of open water – like the one in this photo – so that other resupply ships can reach McMurdo Station.
These parents are going to get food for their chicks, says Ainley. But they won’t be doing this for much longer. In one to two weeks, by mid-to-late February, they and the just fledged chicks with a brand new set of adult feathers will start their winter migration to more northern waters. For the young fledglings, this will be their first experience diving in the Antarctic Ocean and their first journey away from their colony home.
• Stone, Emily. Ice Conditions Send Penguins Packing. The Antarctic Sun, January 29, 2006.
• Lonely Planet Antarctica Guide – 2003.