The number of Emperor penguins in Antarctica is far more than previously thought, according to a study by a team of scientists using satellite mapping technology.
The study led by geographer Peter Fretwell from the British Antarctic Survey (BAS) and a team of international scientists found 44 emperor penguin colonies around the cost of Antarctica, with seven previously unknown.
“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,” said Fretwell.
The results provide an important benchmark for monitoring the impact of environmental change on the population of this iconic bird. The new study used a technique known as pan-sharpening to increase the resolution of the satellite imagery, which helped scientists differentiate between birds, ice, shadow and penguin poo (guano). They then used ground counts and aerial photography to calibrate the analysis. These birds breed in areas that are very difficult to study because, they are remote and often inaccessible with temperatures as low as -50 degree Celsius (minus 58 degree Fahrenheit).
“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 co-author Michelle LaRue from the University of Minnesota and funded by the US National Science Foundation.
BAS biologist Dr Phil Trathan, and co-author of the study, said, “Current research suggests emperor penguin colonies will be seriously affected by climate change. 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.”
Scientists are concerned that in some regions of Antarctica, earlier spring warming is leading to loss of sea ice habitat for emperor penguins, making their northerly colonies more vulnerable to further climate change.
Dr Trathan continued, “Whilst 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. In the future we anticipate that the more southerly colonies should remain, making these important sites for further research and protection.”
The emperor is the giant of the penguin world and one of the largest of all birds. Gold patches on their ears and on the top of their chest brighten up their black heads. Emperors are the only penguin species to breed through the Antarctic winter, with temperatures as low at -50°C and winds of up to 200km (or 124 miles) per hour. They form large colonies on the sea-ice, with the female laying a single egg and passing it to the male for incubation.
This research was carried out by British Antarctic Survey in collaboration with University of Minnesota, National Science Foundation, Scripps Institution of Oceanography and the Australian Antarctic Division.