Per-Gunnar Ostby's Image

Each winter, large numbers of whooper swans escape the cold of Siberia and northern Mongolia, their summer breeding grounds, and migrate to Lake Kussharo on Hokkaido, Japan's northern island.

Here hot springs around this crater lake keep parts of it ice-free. Photographers head here, too, including Per-Gunnar. 'The restless birds in swirling mists', he says, 'are hugely photogenic, though the conditions can be tricky.' The mist often makes it hard to focus and to choose the correct exposure, and on this trip, sub-zero temperatures meant that Per-Gunnar's main camera body lasted only three days. For the next two weeks, he was in constant fear of his second camera body freezing up. 'The swans in this image,' he adds, 'standing on a stage of snow-sprinkled ice, looked so ethereal that the picture just had to be created in black and white.'