Listen to emperor penguin calls here. (British Antarctic Survey)
This species breeds in remote, often inaccessible habitats where temperatures can drop down to minus 58 degrees Fahrenheit (minus 50 C) and winds can reach 124 miles (200 km) per hour, making it difficult to study these giant birds and monitor any impacts of global warming.
The international study used Very High Resolution (VHR) satellite imagery of each colony along the continent’s coastline, fine-tuned by a process called pan-sharpening to improve the resolution and distinguish the birds from ice, shadow, and guano (excrement). Ground counts and aerial photos were used to check for accuracy.
“We are delighted to be able to locate and identify such a large number of emperor penguins,” said study lead author Peter Fretwell at the British Antarctic Survey (BAS) in a press release.
“We counted 595,000 birds, which is almost double the previous estimates of 270,000 to 350,000 birds,” he continued. “This is the first comprehensive census of a species taken from space.”
The researchers were able to monitor 44 colonies with this technique and discovered seven new ones in the process.
“The methods we used are an enormous step forward in Antarctic ecology because we can conduct research safely and efficiently with little environmental impact, and determine estimates of an entire penguin population, said study co-author Michelle LaRue at the University of Minnesota in the release.
“The implications of this study are far-reaching: We now have a cost-effective way to apply our methods to other poorly understood species in the Antarctic, to strengthen ongoing field research, and to provide accurate information for international conservation efforts.”
With this new method, the bird populations can now be overseen relatively cheaply and simply to investigate any changes due to global warming.
“Current research suggests that emperor penguin colonies will be seriously affected by climate change,” said study co-author Phil Trathan, also at BAS, in the release.
“An accurate continent-wide census that can be easily repeated on a regular basis will help us monitor more accurately the impacts of future change on this iconic species.”
In some parts of Antarctica, sea ice melt due to earlier spring warming could be reducing the penguins’ habitat, and exposing northern populations to the effects of climate change.
“While current research leads us to expect important declines in the number of emperor penguins over the next century, the effects of warming around Antarctica are regional and uneven,” Trathan said.
“In the future, we anticipate that the more southerly colonies should remain, making these important sites for further research and protection.”
The study was published in PLoS ONE on April 13 and can be accessed here.