David Tipling / Snow petrel (Pagadroma nivea nivea) flying around Iceberg off South Georgia, Southern Ocean January

Bryan and Cherry Alexander / Emperor penguins (Aptenodytes forsteri) colony, with Snow petrel (Pagodroma nivea) flying past and dark sky. Atka Bay. Antarctica

Bryan and Cherry Alexander / Chinstrap penguins (Pygoscelis antarctica) on a blue iceberg, with Antarctic Prion (Pachyptila desolata) flying over. Antarctica

Chris & Monique Fallows / Pintado petrel (Daption capense) flying in snow, Southern Ocean.

Chris & Monique Fallows / Pintado petrel (Daption capense) flock in flight, Southern Ocean.

Barrie Britton / Southern Giant Petrel (Macronectes giganteus), St Andrew's Bay, South Georgia. Photograph taken on location for the BBC Frozen Planet series, October 2009.

Brent Stephenson / Flock of Cape petrels (Daption capense capense) in flight against the sea. Against the sun. South Shetland Islands, Antarctica, January.

Brent Stephenson / Wilson's Storm-petrel (Oceanites oceanicus) hovering whilst feeding in calm conditions. Cuverville Island, Antarctic Peninsula, Antarctica, December.

Stefan Christmann / Giant petrel (Macronectes giganteus) in flight. Atka Bay, Antarctica. January.

Stefan Christmann / Snow petrel (Pagodroma nivea) in flight. Atka Bay, Antarctica. February.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) sleeping with Snow peterel (Pagodroma nivea) flock in background. Atka Bay, Antarctica. February.

Stefan Christmann / Snow petrel (Pagodroma nivea) in flight. Atka Bay, Antarctica. February.