At the edge of a créche, an emperor penguin is listening for the sound of her offspring, which she recognizes by voice rather than by sight.

Method: No two logistical problems are alike. I wish that were the case, because then by now I would have figured out all the solutions and it would be a routine. But each expedition, each trip, each assignment needs to be customized to the point that I get into the right place at the right time.

Assignment: I found my way to this exclusive gathering after a charter flight in a Hercules cargo plane from South America to the interior of Antarctica, where a twin-engine plane took me and a small party a thousand miles across the continent to a colony along the frozen edge of the Weddell Sea. We landed and pitched camp on the sea ice to spend a month among several thousand emperor penguins arrayed against a surreal backdrop of towering icebergs.