June 23, 2014
Satellite Evidence Shows Emperor Penguins’ Willingness To Relocate
Brett Smith for redOrbit.com - Your Universe Online
Emperor penguins have a reputation for faithfully returning to the same nesting locations every year but a new study from researchers at the University of Minnesota has found that the reality may not fit this reputation.
The study, which is set to be published in an upcoming issue of Ecography, revealed six cases in just three years involving emperor penguins that did not come back to the same area to breed. The report also cited one newly-found colony on the Antarctic Peninsula that may explain the relocation of penguins.
“Our research showing that colonies seem to appear and disappear throughout the years challenges behaviors we thought we understood about emperor penguins,” said study author Michelle LaRue, a polar researcher at the university. “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. These birds didn’t just appear out of thin air—they had to have come from somewhere else.”
“This suggests that emperor penguins move among colonies,” she continued. “That means we need to revisit how we interpret population changes and the causes of those changes.”
Known for being featured in the “March of the Penguins” film, the colony at Pointe Géologie has been studied for more than 60 years. Each year, researchers check the colony for birds that were banded by researchers to go back to the colony. In recent decades, scientists have been worried about how diminishing sea ice may affect the emperor penguins that nest on it.
The study team noted a five-year period during the 1970s during which the Southern Ocean warmed and the penguin colony at Pointe Géologie dropped from 6,000 breeding pairs to 3,000 breeding pairs. The drop was believed to be due to falling survival rates brought about by the warming temperatures.
High-quality satellite images have allowed scientists the ability to see the entire coastline and surrounding sea ice. Because emperor penguins are the only species living on the ice, scientists can study images and identify the birds' presence through their telltale guano stains. Before satellite images, scientists thought Pointe Géologie was cut off and there was nowhere else for the penguins to live. However, satellite images indicate that Pointe Géologie isn't as isolated as previously thought, with numerous colonies being within easy travel distance for an emperor penguin.
The study team said their work offers evidence that the penguins may be able to adapt to potential changes that could come about as a result of global warming.
“It’s possible that birds have moved away from Pointe Géologie to these other spots and that means that maybe those banded birds didn’t die,” LaRue said. “If we want to accurately conserve the species, we really need to know the basics. We’ve just learned something unexpected, and we should rethink how we interpret colony fluctuations.”
LaRue was among the authors in another study published last year that found Adelie penguins living in Antarctica could actually benefit from rising global temperatures. According to that study, penguin population on Antarctica's Beaufort Island increased 84 percent as the region's ice fields retreated from 1958 to 2010.