Mr. Popper may have had too many penguins, but today Antarctica seems to have too few.
Disruptions in the food supply, caused in part by warming climate, are to blame for shrinking populations of Adélie and chinstrap penguins across the West Antarctic Peninsula, a team of U.S. researchers argues. Rising temperatures alone are bad for these cool, tuxedoed birds, but the penguins’ struggles primarily stem from having too few krill to eat, the group reports online April 11 in the Proceedings of the National Academy of Sciences.
Study coauthor Wayne Trivelpiece has kept a close eye on penguins off the tip of the West Antarctic Peninsula, which points fingerlike at Argentina, since the 1970s. Winter temperatures there and in the nearby Scotia Sea have climbed a whopping 5 to 6 degrees Celsius in recent decades.
In the early 1990s, Trivelpiece and his colleagues argued that shrinking ice masses might be a mixed blessing for penguins. Icebound Adélies (Pygoscelis adeliae) were expected to hurt, while the more free-roaming chinstraps (Pygoscelis antarctica) would hunt better with less ice. Instead, from the 1980s on populations of both species plummeted by more than half across the study sites.