Scientists Use Satellite Images to Take Emperor Penguin Census
Posted on April 13, 2012
A new study, reported here in PLoS ONE, used satellite mapping technology to reveal that there are twice as many emperor penguins in Antarctica than previously thought. The results of the satellite emperor penguin census provide an important benchmark for monitoring the impact of environmental change on the population of the emperor penguin, which breeds in remote areas that are very difficult to study because they often are inaccessible with temperatures as low as -58 degrees Fahrenheit.
Lead author and geographer Peter Fretwell at British Antarctic Survey (BAS), which is funded by the U.K.'s Natural Environment Research Council, says, "We are delighted to be able to locate and identify such a large number of emperor penguins. We counted 595,000 birds, which is almost double the previous estimates of 270,000-350,000 birds. This is the first comprehensive census of a species taken from space."
On the ice, emperor penguins with their black and white plumage stand out against the snow and colonies are clearly visible on satellite imagery. Using a technique known as pan-sharpening to increase the resolution of the satellite imagery, the science teams were able to differentiate between birds, ice, shadow and penguin poo (guano). They then used ground counts and aerial photography to calibrate the analysis.
Co-author Michelle LaRue from the University of Minnesota, funded by the U.S. National Science Foundation (NSF), says, "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 on-going field research, and to provide accurate information for international conservation efforts."