Adélie penguins in Antarctica are in the midst of a major upheaval as climate change causes their icy habitat to warm up, experts say.
Some populations of the birds are thriving, but most are declining rapidly.
The penguins rely on winter sea ice as a platform for feeding on ocean krill.
But they also need the ice to shrink in the summer so they can access their breeding colonies on land.
The mid-latitudes of the Antarctic Peninsula once provided the perfect habitat for the penguins—but not anymore.
"That region has experienced the most rapid warming during winter on the planet," said Bill Fraser, an ecologist with the Polar Oceans Research Group in Sheridan, Montana.
"The mid-winter temperatures are now around 10.8 degrees Fahrenheit [6 degrees Celsius] higher than they were 50 years ago."
If the trend continues, Fraser predicts that Adélie penguins will be locally extinct within five to ten years.