New study challenges theory that emperor penguins return to same area each year
Philopatry is the tendency of an organism to stay in, or return to its home area. Many animal species are considered philopatric because they often return to their birthplace year after year to breed. Revisiting the same site is advantageous because nests and courtship areas have already been established while competition from other animals is largely non-existent due to territoriality.
Researchers have long thought that emperor penguins were a prime example of this phenomenon, however a new study shows that this species may be adapting to changing environments and may not necessarily be faithful to previous nesting locations.
Led by the University of Minnesota, the new study found six instances in just three years in which emperor penguins did not return to the same location to breed. Researchers also report on one newly discovered colony on the Antarctic Peninsula that may represent the relocation of penguins.
University of Minnesota College of Science and Engineering researcher and the study's lead author Michelle LaRue says, "Our research showing that colonies seem to appear and disappear throughout the years challenges behaviors we thought we understood about emperor penguins ... 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. That means we need to revisit how we interpret population changes and the causes of those changes."
High-resolution satellite imagery has allowed researchers to now see the entire coastline and all the sea ice. Because emperor penguins are the only species out on the sea ice, they can look at images and identify their presence through the telltale sign—their guano stain.
"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."
The study will be published in the journal Ecography.
Read more at the University of Minnesota.
Emperor penguin image via Shutterstock.