The Greatest Penguin Mystery
A chilly wind swept through the island as a couple huddled closer and made eye contact huddled closer and stared into each other’s eyes. They were clearly a male and female pair, bonded for life, and their frightened expressions and tense body language suggested that they were worried about something beyond their control.
“Did you find them?” she asked her husband.
“No, I looked everywhere I could, and it’s just like the others. I can’t find them and no one knows where they went,” he responded.
The numbers of missing were growing daily. Although they didn’t know it, over 165 had gone missing yesterday, and nobody knew where they were or why they had disappeared..
She moved around to face her husband. “I’m scared,” she said, barely louder than the wind.
“Me too,” he responded solemnly, then pointed his beak down between looking at an egg underneath him. He silently wondered to himself how they would all survive.
… This might be how the penguins on the Île aux Cochons island felt as over 1.8 million penguins disappeared around them at a rate of 110 penguins a day for 30 years…
The Site of the Formerly World’s Second Largest Penguin Colony
The Île aux Cochons island is home to a penguin colony that once housed 2 million King penguins with 500,000 breeding pairs, based on a count from 1982. However, based on current satellite images, there are now only 200,000 King penguins with 60,000 breeding pairs. Over the span of 30 years the colony’s population decreased by 1.8 million — more than the current population of the city of Philadelphia.
The Île aux Cochons island is located between the southern tip of Madagascar and Antarctica, about 1,800 miles southeast of Johannesburg, South Africa. The island is part of the French Southern and Antarctic lands (TAAF). Discovered and claimed by the French in 1772, it was later made part of TAAF in 1955. The island is 25 square miles and has an ancient volcano cone, Morne du Tamaris, from which the nearby King penguin colony gets its name.
Penguin Populations Visible from Space
The area is remote and not easily accessible so visits and population counts from the scientists are infrequent due to the prohibitive cost. Instead, the team from Chizé Centre for Biological Research in France examined satellite photos. Researchers can use satellite images to track Emperor penguin colonies on the Arctic ice. However, population counts are difficult since satellite images of guano can be difficult to quantify in relation to a colony’s size.
Scientists like Henri Weimerskirch are able to determine the colony size based on areas without vegetation. King penguins do not build nests, and their density when they are in a colony and sitting on eggs is about one flipper-length between penguins — or, more precisely, 1.6 – 2.2 penguins per square meter, huddling together for safety and warmth.
© Henri Weimerskirch, Satellite Photo from April 2017.
Call outs by Jasper Morse
The primary site of the penguin colony is to the west of Morne du Tamaris where there is a barren area which the king penguins would occupy. The route from that colony is outlined in yellow above to the ocean on the east side of the island. A much smaller king penguin was found between the primary penguin colony and the coast.
When penguins live in an area, they trample the vegetation in the space and prevent it from growing. Knowing this, satellite photos can be examined to see if the areas with vegetation are increasing, meaning penguin-occupied area is decreasing since vegetation takes over when penguins leave.
Knowing this and comparing against population counts and available information from helicopter surveys from 1962, 1982, 2016 and satellite photos from 1988, 2005, 2015 and 2017, researchers are confident there has been a massive decline in what was once the world’s second largest penguin colony.
© Peter Ryan
Northern view of colony from helicopter on December 30, 2016.
The above image taken by Henri during a 1982 survey shows the penguins massive population on the island.
The Greatest Penguin Mystery
How did a penguin colony size reduce by the population of the city of Philadelphia? There are some prevailing theories that Henri Weimerskirch has, but work on the ground and additional investigation are required to gather more information. Additionally, there is no single theory currently that could confidentially account for the massive decline. The initial theories include El Nino changes in the ocean temperature from the 1980s, disease could have ravaged the colony, or predators in the form of cats or mice.
There is a potential correlation between El Nino activities in the 1980s and the population decline. Temperature changes in the ocean can cause changes in location or behavior of the primary food source of fish for the Penguins.
During my time on Robben Island, a similar hypothesis had been proposed to explain the changes in breeding habits with the South African penguins. Penguins do not move colonies easily and are unable to follow their prey to new locations because the new area may lack adequate living conditions for the penguins. For the South African penguins the changes in prey availability can increase chick survival rates, but the population could still decline due to less chicks being born.
Cats and mice do occupy the islands, as noted from a researcher’s visit during the 1970s. While neither cats or mice are traditionally known as King penguin predators, there has been research showing that both have attacked albatross, and it is possible that they may have attacked the resident penguins as well
With the King Penguins on Île aux Cochons there is a newly discovered colony on the island between the main colony and the ocean shore on the east side of the volcano cone. The number of penguins in this colony, however, only amounts to a few 10s of thousands and does not account for the 1.8 million penguins that are now missing.
Permits, Ships, Research, Research, Research
There has been significant coverage on massive decline of the King Penguin population with articles written from the Smithsonian & Gizmodo to The Japan Times. The Nature Reserve that manages the location is now ready to provide permits to visit the island and investigate further. Funding support from the French Polar Institute is also underway to help get scientists to the island to gather more data. The project also requires additional funding, ships, and a time when the ships, researchers and equipment can all be in the same place to go to Île aux Cochons. Until then, researchers will continue to monitor the area via satellite and other researchers will carefully monitor their colonies as well.
References:
Primary Resource and Scientific Paper –
Massive decline of the world’s largest king penguin colony at Ile aux Cochons, Crozet: https://www.cambridge.org/core/journals/antarctic-science/article/massive-decline-of-the-worlds-largest-king-penguin-colony-at-ile-aux-cochons-crozet/E254E3E24DE3BDC523B25FA3A3261584
CIA Factbook on Ile aux Cochons: https://www.cia.gov/library/publications/the-world-factbook/geos/print_fs.html
NASA Article about Penguin Tracking using Satellites:
Scientists Map Penguins From Space with Landsat
US Population Data (Google)
Google news articles about the King Penguin population decline
2 Comments
Gloria Morse
This is interesting, Jasper. There definitely has to be reason for that many of those little guys to disappear.
Jasper
It is disturbing, and I’m hoping that with enough attention and research scientists can figure out what happened so we can stop it from happening to other penguin colonies.