When an animal species depends on sea ice for a good part of its life cycle, what are they going to do when that sea ice starts to melt and disappear due to climate change? Well for some colonies of emperor penguins, it appears the only solution is to move away from that melting sea ice – even if it means climbing up the very steep sides of floating ice shelves to find safer breeding sites.
The new behavior – described this week in the journal PLoS One – was observed in four of the 46 known emperor penguin colonies in Antarctica. These birds normally "tend to breed on the sea ice because it gives them relatively easy access to waters where they hunt for food," lead research Peter Fretwell of the British Antarctic Survey (BAS) said in a press release. But with sea ice at reduced levels around Antarctica lately, Fretwell and his fellow researchers observed four groups of penguins which did not follow this normal behavior.
According to Fretwell, the sea ice in some locations in 2011 and 2012 was not strong enough to support the normal breeding colonies. "The sea ice did not form until a month after the breeding season began," he said. "During those years the birds moved up onto the neighboring floating ice shelf to raise their young." Two colonies moved during both years, while the remaining two each only moved one year.
It wasn't an easy journey. Fretwell called it "a very difficult maneuver" which required the penguins to climb 30 meters (nearly 100 feet). Considering that emperor penguins are rather ungainly — or, as Fretwell puts it, "clumsy" — on land, that's quite a feat.
While the news that the penguins had to abandon their normal breeding sites is disturbing, the researchers do point out a silver lining: the fact that they moved means they "may be capable of adapting their behavior" to fit a newly warming world.
Co-author Barbara Wienecke of the Australian Antarctic Division said that "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 behavior is widespread in other penguin populations. 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."
The behavior was observed via satellite and probably would not have been noticed without that eye in the sky. Another co-author, Gerald Kooyman of the Scripps Institution, said "it is likely that there are other nuances of the emperor penguin environment that will be detected sooner through their behavior than by more conventional means of measuring environmental changes."