Stefan Christmann / Adelie penguin (Pygoscelis adeliae) calling during courtship, Atka Bay, Queen Maud Land, Antarctica, December.

Stefan Christmann / Adelie penguin (Pygoscelis adeliae) nesting pair, Atka Bay, Queen Maud Land, Antarctica, December.

Frederique Olivier / Adelie penguins (Pygoscelis adeliae) swimming underneath sea ice, Antarctica.

Frederique Olivier / Wide-angle shot of a group of Emperor penguin (Aptenodytes forsteri) chicks walking on sea ice, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) chick begging for food from parent, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) walking with chick, Adelie Land, Antarctica, January.

Frederique Olivier / Close-up of a group of Emperor penguin (Aptenodytes forsteri) chicks huddled together in a blizzard, covered in snow, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) chicks huddled together during a blizzard, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguins (Aptenodytes forsteri) walking in blizzard, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguins (Aptenodytes forsteri) walking and tobogganing in blizzard, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) chicks calling, with another small chick arriving and falling over, Adelie Land, Antarctica, January.

Frederique Olivier / Group of Adelie penguins (Pygoscelis adeliae) swimming in a tide crack, lots jump out, Adelie Land, Antarctica, January.