From the Antarctic: Bird's-eye view under ice

Herald photographer Mark Mitchell took this photo of an emperor penguin diving under the ice from an observation tube lowered through about 3m of sea ice at Dr Paul Ponganis' "penguin corral" in McMurdo Sound in Antarctica.

"I climbed down a ladder and sat on a box. I didn't even have my gloves on," he said.

He took the photo at a 40th of a second with 800 ASA digital film on a 35mm camera set at about F5.

Dr Ponganis and his American and Japanese colleagues use the observation tube to record the way the penguins dive, and the way they glide back up to the surface at an oblique angle, slowing down as they ascend.

The tube is frozen solid into the sea ice, but will be dismantled, with the rest of the corral, when the sea ice begins to melt next month.