Where on earth were all the penguins?

Science Magazine Mar. 19, 2020

Where on Earth, wondered Henri Weimerskirch, were all the penguins? It was early 2017. Colleagues had sent the seabird ecologist aerial photos of Île aux Cochons, a barren volcanic island halfway between Madagascar and Antarctica that humans rarely visit. The images revealed vast areas of bare rock that, just a few decades before, had been crowded with some 500,000 pairs of nesting king penguins and their chicks. It appeared that the colony—the world’s largest king penguin aggregation and the second biggest colony of any of the 18 penguin species—had shrunk by 90%. Nearly 900,000 of the regal, meter-high, black, white, and orange birds had disappeared without a trace. “It was really incredible, completely unexpected,” recalls Weimerskirch, who works at the French national research agency CNRS.

Soon, he and other scientists were planning an expedition to the island—the first in 37 years, and only the third ever—to search for explanations. “We had to go see for ourselves,” says CNRS ecologist Charles Bost.

As the researchers prepared for the journey, they had to grapple with the logistical, political, and scientific challenges that have long bedeviled biologists trying to understand Antarctica’s remote ecosystems. The vast distances, rough weather, and rugged terrain make travel difficult and expensive. They needed a ship—and a helicopter, because frigid seas and rocky shores make for perilous boat landings on Antarctic islands. Complying with the tough permitting and biosecurity rules governing the French-controlled island—meant to prevent researchers from disturbing fragile ecosystems—required careful planning and paperwork that took months to complete. And once they arrived, they would have precious little time: just 5 days to investigate a multitude of suspects in the disappearance, including disease, predators, and a warming Southern Ocean.