Alain Hubert relies on ground truth to aid satellite-based research at a newly discovered penguin colony in Antarctica.
Emperor
penguins, adults and babies, cluster in December 2013 at recently
discovered Ragnhild colony in Antarctica. On its second visit, a team
from the International Polar Foundation estimated the population at
15,000 birds.
PHOTOGRAPH COURTESY OF INTERNATIONAL POLAR FOUNDATION
Angie McPherson
National Geographic
Published February 19, 2014
Alain Hubert counts penguins as a hobby. His day job is collecting climate data as a summer resident at the
Princess Elisabeth Antarctica
research station. For someone needing a penguin fix, he is in the right
place. More than a million emperor penguins inhabit the rugged
Antarctic coastline. And when satellite images revealed a previously
unknown colony near the research center, the Belgian adventurer knew he
had to find them and bring back a count.
The satellite images, from a 2009 research project conducted by the
British Antarctic Survey and
reported in Global Ecology and Biogeography,
did not discern individual penguins. Instead they showed large patches
of reddish brown guano clearly visible against the white surroundings,
evidence of where a penguin colony had spent the winter huddled on the
frozen coast.
When researchers decoded the satellite images, they found
ten new emperor penguin colonies in 2008 and four more in 2009. Hubert
studied the results and saw on the map that one colony was located not
far from his research facility. That was all the incentive he needed to
start searching in his spare time around the Ragnhild coast.
It was challenging terrain. "There were crevices everywhere
and many places where we couldn't take our Ski-Doo," said Hubert, an
experienced mountaineer who leads expeditions while working at the
station, established in 2009 by the
International Polar Foundation. For parts of three years he looked for the colony.
PHOTOGRAPH COURTESY OF INTERNATIONAL POLAR FOUNDATION
Adult penguins take a break on the ice. Since
adults spend much of the summer months hunting in the sea, the colony is
mostly populated by the young.
Finally, on a December night in 2012, the Antarctic summer
sun above the horizon, Hubert and a team of fellow explorers found what
they were looking for. "We were walking on the edge of the shore, standing above
the black ocean, when we came across these cliffs that stood 40 meters
[131 feet] high," he said. In a rift by the cliffs' side, he saw a huge
gathering of baby penguins.
In a few hours of walking the ice, Hubert counted 3,000
newborns with their distinctive gray down. (Adult penguins jump in and
out of the ocean and are too difficult to count.) He multiplied that
number by three for a rough estimate of 9,000 penguins, including
parents and bachelors.
The Ragnhild colony turned out to be some 170 miles (274
kilometers) from the research station, a 12- to 16-hour journey by
Ski-Doo. With photos and research notes in hand, the adventurers made
their way back and soon reported their findings to the British Antarctic
Survey.
Penguins From Space
MAGGIE SMITH, NG STAFF. SOURCES: SIERRARIOS; WRI; WWF
Satellites and Ground Truth
Hubert's old-fashioned method of counting contrasts with
the computer-aided survey from space. "We tell the computers how to
differentiate between the guano [reddish brown pixels] and the penguins
[black pixels]," said Michelle LaRue, researcher and author of
the first satellite penguin census in 2012.
This study used images from the 2009 satellite study to estimate the
number of emperor penguins in Antarctica, a first for researchers. From
the photos, she estimated that there are a total of 595,000 emperor
penguins in 44 different Antarctic colonies.
Though the numbers generated from satellite images are
imprecise, they remain the most efficient and reliable tool for locating
and sizing penguin colonies. Yet nothing beats ground truth. A year
after his first visit, Hubert again found himself in the vicinity of the
Ragnhild colony. Because of moving ice, the ship that delivered
supplies to the research station had to dock farther than usual from the
usual drop-off point. Unpacking the ship, Hubert realized that he was
less than 80 miles (129 kilometers) from the penguin colony. He felt
compelled to visit again.
PHOTOGRAPH COURTESY OF INTERNATIONAL POLAR FOUNDATION
By the end of January, these baby penguins will molt their gray down and grow waterproof feathers.
Facing only a four-hour journey to Ragnhild this time, he
and field guide Christophe Berclaz left on Ski-Doos. "Since the ice is
continuously moving, the first and second trips were completely
different," said Hubert, "but once you learned the entrance rift to the
colony, you can move much quicker."
Cloud and fog cleared as Hubert and Berclaz arrived in
Ragnhild. "It was a scene you could transpose onto a beach somewhere,"
joked Hubert. Below the cliffs the baby penguins were huddled in loose
groups, standing in the reflection of the sun from the water. Hubert and
Berclaz spent nearly ten hours counting the juvenile penguins. The good
weather enabled them to count more penguins than they did on their
first journey.
By the end of the day, they had estimated there were 15,000
penguins at Ragnhild, a leap of 6,000 from the previous count and a
similar figure to that of the satellite-derived figures from
LaRue's census in 2012. "This groundwork is encouraging for researchers," said
LaRue about Hubert's visits. "It may tell us that Ragnhild is a
relatively stable colony."
The fact that the human count was close to the satellite
count suggests that satellites are reliable tools for census taking.
What ground visits provide that satellite research doesn't are valuable,
up-close observations and descriptions. But making good counts isn't
the only thing that drives Hubert's trips to the colony. He returned, he
said, to satisfy himself that the population of emperor penguins at
Ragnhild wasn't shrinking.
PHOTOGRAPH COURTESY OF INTERNATIONAL POLAR FOUNDATION
Emperor penguins are the largest of all penguins.
They can grow up to 45 inches (114 centimeters) tall and weigh up to 88
pounds (40 kilograms).
Future Monitoring
As a polar explorer and climate researcher, Hubert is concerned that
melting sea ice
could make it harder for penguins to find food sources, ultimately
reducing emperor penguin populations in the coming decades. "We're all
working together to answer questions about the state of the food chain
in Antarctica, such as krill, the birds, etc. But it's so difficult to
monitor in this huge territory," said Hubert. "Antarctica is twice as
big as the whole United States."
PHOTOGRAPH COURTESY OF INTERNATIONAL POLAR FOUNDATION
Emperor penguins slide and waddle to the icy shoreline, ready to plunge into the freezing sea.
When Hubert walked the grounds of the colony, he spotted
only a few dead baby chicks, a sign that the population had made it
through the winter successfully. But he won't know until next year on
his anticipated return if the adult penguins found enough food under the
sea ice to survive the molting season. (Learn more about the
penguin molting season.) Already a few scientists have requested to join him later in 2014 to conduct studies.
After counting the penguins, Hubert headed back to the
research center. It had been another worthwhile visit. He left the
colony in high spirits, hoping that he would see the Ragnhild penguins
again. He jumped back on the Ski-Doo, covered his face from the brisk
winds, and drove back across the jagged ice rift, following the
seemingly endless white snow line on the horizon.
