They marched in orderly ranks, three abreast, like emperor penguins in a nature film.

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In addition, they used a "population dynamics" model describing the mating patterns and breeding success of emperor penguins.

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Antarctica is rich in wildlife, from whales to sea lions to Emperor penguins and many other species of birds.

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Emperor penguins, the largest species, are unique in that they are the only penguins that breed during the harsh Antarctic winters.

BBC: Emperor penguins face extinction

By using satellites, the researchers were able to conduct their census when the emperor penguins were still gathered at their breeding grounds to tend their young.

WSJ: Emperor Penguins Aplenty in Antarctica

While at the camp, guests can participate in a variety of activities, including exploring ice caves, visiting a nearby science base, kite-skiing or touring a colony of Emperor penguins, where more than 6, 000 of the flightless birds nest and raise their chicks.

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Previous attempts to count emperor penguins systematically have been thrown off because field biologists could survey the penguin rookeries only during the extended daylight of the Antarctic summer, when conditions are relatively balmy and the penguins usually are scattered, feeding at sea.

WSJ: Emperor Penguins Aplenty in Antarctica

"For penguins, it is particularly important, because there are predictions that we might lose emperor-penguin colonies due to changing environmental conditions, " Mr. Fretwell said.

WSJ: Emperor Penguins Aplenty in Antarctica