January 9, 2014
Shrinking Habitat Doesn’t Keep Emperor Penguins From Breeding
[ Watch the Video: Emperor Penguins Are Breeding On Ice Shelves ]
The emperor penguins of Antarctica, which have lost much of their breeding habitat due to shrinking ice pack, have shown their resiliency to environmental impacts by moving to new breeding locations where ice is thicker, as has been seen via satellite images, reports BBC News' Jonathan Amos.
A new study, published in the online journal PLOS ONE, describes the great distances these penguins march to find an alternate place to breed. These alternate sites are towards the coast, up over ice shelves and onto thicker glaciers. They consist of cliffs sometimes 100 feet tall, but the birds manage to scale them to reach their goal.
Lead author Peter Fretwell, from the British Antarctic Survey said, “We thought that in years when the sea ice was bad, they just didn't breed, but they're clearly more adaptable than that.”
The emperor species is the most southerly Antarctic breed of penguin and only breed on seasonal sea ice. The patterns of these in the recent years has caused the emperor penguin to be placed as “near threatened” on the IUCN Red List.
“When they go out from the colony to forage, they go down the steep cliff - the shortest route to the sea. We're not sure how they get down - they may slide down or jump down. But this cliff is too steep for them to climb back up and so they must return a different way, likely through an ice creek. This route is 5km longer and we know they take it because we can see their tracks in the satellite pictures,” Fretwell told BBC News.
“These charismatic birds tend to breed on the sea ice because it gives them relatively easy access to waters where they hunt for food. Satellite observations captured of one colony in 2008, 2009 and 2010 show that the concentration of annual sea ice was dense enough to sustain a colony. But this was not the case in 2011 and 2012 when the sea ice did not form until a month after the breeding season began. During those years the birds moved up onto the neighbouring floating ice shelf to raise their young,” explained Fretwell in a separate statement.
He added, “What's particularly surprising is that climbing up the sides of a floating ice shelf – which at this site can be up to [100 feet] high – is a very difficult manoeuvre for emperor penguins. Whilst they are very agile swimmers they have often been thought of as clumsy out of the water.”
Gerald Kooyman, of the Scripps Institution said: “Without satellite imagery these moves onto shelf ice would not have been detected. It is likely that there are other nuances of the emperor penguin environment that will be detected sooner through their behaviour than by more conventional means of measuring environmental changes.”
“These new findings are an important step forward in helping us understand what the future may hold for these animals. However, we cannot assume that this behaviour is widespread in other penguin populations," Barbara Wienecke, of the Australian Antarctic Division, said in a statement, as cited by the Daily Mail.
"The ability of these four colonies to relocate to a different environment - from sea ice to ice shelf - in order to cope with local circumstances, was totally unexpected. We have yet to discover whether or not other species may also be adapting to changing environmental conditions,”Wienecke added.
Four colony sites were focused on: Barrier Bay, the Jason Peninsula, Ruppert Coast and Nickerson Ice Shelf. The images and data gathered were analyzed to identify the terrain and track the movement of the colony of penguins.