Antarctic Penguin Census Shows Seabirds Are Thriving
Considered a bellwether of climate change, the Antarctic seabird’s population is generally on the rise
Rather than declining as feared, the Adélie penguin population generally is on the rise, scientists say.Stony Brook University
For the first time, researchers have counted all the world’s Adélie penguins—a sprightly seabird considered a bellwether of climate change—and discovered that millions of them are thriving in and around Antarctica.
Rather than declining as feared due to warming temperatures that altered their habitats in some areas, the Adélie population generally is on the rise, the scientists said Thursday.
“What we found surprised everyone,” said ecologist Heather Lynch at Stony Brook University in Stony Brook, N.Y., who led the penguin census. “We found a 53% increase in abundance globally.”
Counting the birds by satellite, Dr. Lynch and imaging specialist Michelle LaRue at the University of Minnesota found that the Adélie penguin population now numbers 3.79 million breeding pairs—about 1.1 million more pairs than 20 years ago. In all, they identified 251 penguin colonies and surveyed 41 of them for the first time, including 17 apparently new colonies.
The researchers found eight abandoned penguin colonies on the Antarctic Peninsula, where regional temperatures have been rising faster in recent decades than across the continent as a whole.
That loss, however, was offset by new colonies that sprouted up elsewhere in Antarctica and by growth in previously known colonies since the last general penguin census was carried out in 1993, the scientists said.
“The gains on the continent more than offset the losses on the peninsula,” Dr. Lynch said. “For now, that is good news.”
Their bird count, published online this week by the American Ornithologists’ Union, mirrors a satellite survey of Emperor penguins conducted in 2012 by geographers at the British Antarctic Survey who discovered that the isolated icebound continent was home to twice as many Emperor penguins as scientists had thought.
Wildlife biologists pay close attention to Adélie penguins because their well-being is tied to annual sea ice conditions and temperature trends. They nest in groups on exposed rock but have to walk to the ice edge to feed in open water.
While annual sea ice in the Arctic has declined dramatically in recent years, the seasonal sea ice around the mainland of Antarctica has reached record levels. The 800-mile-long Antarctic Peninsula, which reaches above the Antarctic Circle toward South America, is relatively mild compared with the mainland. Temperatures there have risen about 2.8 degrees C in the past 50 years, records show.