Thursday, February 27, 2014

Antarctica Flashback

It's already a year since I spent 6 weeks in Antarctica...time for a flashback!

This blog I would like to dedicate to one highly adapted bird, also the icon of Antarctica, the penguin.

Follow the Gentoo Penguin, Pygsocelis papua, as it masters mission impossible, raising young  on the White Continent.

At the beginning of the Antarctic summer, the Gentoos start building their nests or remodel older nests. They typically have their colonies near the shore line on snow free ground.
Most of the colonies though are on higher ground, to be safe from flooding.

If the way from the breeding ground to the open water is covered in snow, the penguins will create paths in the snow that they will use over and over again, so-called penguin highways, that make it easier to waddle up and down the slopes.

They nest in colonies ranging in size from only a few to thousands.

Pebbles play an important role for the Gentoos, they build their nests with them and seem to be very picky as for which pebble might be just the right one for a certain space. A male might even bring a especially nice pebble to a female to impress her...pebbles are a girls best friend...;-)
Even the youngsters can be seen playing with little rocks.
A Gentoo nest can contain as many as 1700 of these pebbles!
Although Gentoo Penguins reach maturity with the age of two, they usually start to reproduce around 3 to 4 years old. By that time a male looks for a good potential nest site and tries to attract a female. Once they find together, Gentoo Penguins tend to stay together for life.

Early in the Antarctic summer the female lays two eggs within three days. Both partners share the task of incubating the eggs for 35 days. Although both parents try hard, not all eggs get to hatch.

Some roll out of the nest, many get robbed and eaten by Skuas. One afternoon on Cuverville Island I was watching a incubating penguin being distracted by a neighborly dispute. A Skua spotted this instantanously, flew in with lightning speed and stole the egg. The parent realized what just happened and was most distraught and kept looking and calling for some time. Quite heartbreaking.

After the chicks hatch they stay in the nest under close supervision for about 3-4 weeks

And again both parents share the task of either defending the nest or finding food for the chicks and themselves

After this close nest period, the youngsters are huddled together in so called creches, a kind of Gentoo kindergarten, so that both parents can go and find food.

At around 70 days old, the little ones will fledge and explore their surroundings more and more.

During that time, until they finish their first molt from "baby" feathers to waterproof adult feathers and become independent, they will still call for their parents, each parent and chick is able to distinguish between it's parent/chick in between hundreds of other penguins, and

their parents will still come and feed them. The feeding of the young works via regurgitation...a rather noisy and a bit stinky business as I was lucky enough to observe closely. But also highly effective, nothing is wasted.

With about 100 days, the young Gentoo penguins reach their independence. Their molt will have completed and they are ready to go into the water and look after them self. However only 30% to 50% survive the first year. The Skuas are a serious threat for the eggs and the small chicks and once they are too big for the Skuas and ready to go into the water, seals, especially Leopard Seals, will wait for the inexperience youngsters.

Once the fledglings have made their final departure, the adults start their annual molt. For a good three weeks they seem to stoically endure the ordeal of a complete change of feathers. During this time they can't go into the ocean and hence they do not eat during that time.

Once the molt is completed though, life goes on as usual. The Gentoo Penguins breeding on the Antarctic Peninsula will seek out ice free regions farther north during the Antarctic winter months and return in spring to start all over....

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