Emperor penguins, long thought to be tied to a single breeding location they would return to year after year, have shown they're willing to relocate their nesting grounds in response to climate change, a study has found.
Using satellite images, researchers from the University of Minnesota tracking penguin colonies over three years have seen six instances of penguins relocating in response to changing temperatures.
Scientists had previously believed emperor penguins returned to the same breeding grounds annually, in what is known as philopatric behavior.
But the researchers studying the penguin colony that was featured in the documentary film "March of the Penguins" saw the group -- the subject of studies for over 60 years -- decline in size in recent years.
First the decline was attributed to reduced survival rates, but it turns out the change may simply be because not all penguins are tied to a single location for breeding, the researchers say.
That assumption was strengthened by the discovery of new colonies in satellite images that could be a sign of relocation of some penguins, they say.
"Our research showing that colonies seem to appear and disappear throughout the years challenges behaviors we thought we understood about emperor penguins," says UM researcher Michelle LaRue.
"If we assume that these birds come back to the same locations every year, without fail, these new colonies we see on satellite images wouldn't make any sense," she says. " These birds didn't just appear out of thin air -- they had to have come from somewhere else."
The "March of the Penguins" colony at a location known as Pointe Géologie is studied every year by researchers. Before satellite imagery became available as a research tool, scientists had believed the location was isolated, giving the penguins there nowhere else to go.
There has been concern in recent years that retreating sea ice caused by climate change could be affecting the colony that breeds on it.
But the satellite images, which allow scientists to see both the entire coastline along with all of the surrounding sea ice, showed Pointe Géologie isn't isolated at all. The images show a number of colonies and possible new colony locations within distances that would be easy for emperor penguins to travel to.
That knowledge and the new satellite images of previously unknown gatherings of the emperor penguins suggests they aren't necessarily faithful to previous breeding locations and can, if necessary, adapt to climate change and its changing temperatures.
"That means we need to revisit how we interpret population changes and the causes of those changes," LaRue says.
Lead author LaRue shared the study's findings at the IDEACITY conference in Toronto this month. It also will be published in Ecography, a professional journal publishing research in spatial ecology and biogeography.
