The first count of a species from space shows there are twice as many emperor penguins in Antarctica than previously thought, an international team of researchers revealed last week.
Emperor penguin colony [British Antarctic Survey]
Scientists from the British Antarctic Survey, University of Minnesota/National Science Foundation, Scripps Institution of Oceanography and the Australian Antarctic Division collaborated on the survey, using high-resolution satellite mapping technology.
Lead author and geographer Peter Fretwell at the British Antarctic Survey said the research findings are groundbreaking because they provide a benchmark for monitoring how the penguins are affected by environmental change.
"We are delighted to be able to locate and identify such a large number of emperor penguins," Fretwell said. "We counted 595,000 birds, which is almost double the previous estimates of 270,000 to 350,000 birds. This is the first comprehensive census of a species taken from space."
The research was published in the journal "PLoS ONE" on April 14. In the article, the scientists describe how they used very high resolution satellite images to estimate the number of penguins at each colony around the Antarctic coastline.
The emperor is the giant of the penguin world and one of the largest of all birds. On the ice, black and white emperor penguins stand out against the snow and their 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 guano. They then used ground counts and aerial photography to calibrate the analysis.
The team to analyzed 44 emperor penguin colonies around the coast of Antarctica, including seven colonies that were previously unknown.
Co-author Michelle LaRue from the University of Minnesota Polar Geospatial Center said, "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."