This satellite image shows white Antarctic ice stained brown by Emperor penguin guano
Satellite images have picked up giant red-brown stains on the pristine white sea ice, indicating the presence of thousands of penguins.
It meant that researchers for the British Antarctic Survey were able to locate every colony on the continent for the first time ever.
The in-depth satellite survey identified 38 breeding colonies – believed to amount to between 200,000 and 400,000 breeding pairs of emperor penguins.
Until now it has been difficult to accurately estimate the population of emperor penguins because scientists have not been able to track them during the winter breeding season.
Researchers now hope by tracking the penguin colonies they can monitor the impact of climate change, which threatens to wipe out 95 per cent of the population by 2100.
Emperor penguins spend a large part of their life at sea and during the Antarctic winter, when temperatures drop to -58F (-50 C), they return to their colonies to breed on sea-ice.
This makes it extremely difficult for scientists to follow them and means previous knowledge on the number and distribution of emperor penguin colonies was poor.
The survey, published today (Tues) in the Global Ecology and Biogeography journal, reveal ten new colonies have appeared while six previously-known ones have relocated.
Peter Fretwell, co-author of the study and geographic information officer at British Antarctic Survey, said his chance discovery would revolutionise the way scientists monitored penguins.
He said: “This is the first part of an ongoing study. Now we can locate the colonies we will be able to go out and get an accurate count of the total breeding population.
“It was a very serendipitous discovery and a chance encounter when I realised I could see the stains.
“They look like reddy-brown stains on the sea ice, which is formed every year in the Antarctic winter and usually looks absolutely pristine and white.
“No other birds breed on the sea ice and each colony can have tens of thousands of birds in it.
“Emperor penguins are quite big birds and it gets quite messy and very smelly.
“Sometimes I think remote sensing is the best way to monitor them as you really don’t want to get too close.”
Mr Fretwell had been mapping a British Antarctic Survey base near the Halley station on the Brunt ice shelf in October 2008 when he noticed a brown stain on the satellite images.
He said: “It was a bit of a eureka moment. I realised if I could see this colony with satellites I should be able to see more.”
Using a satellite mosaic of Antarctica Mr Fretwell and his colleagues managed to survey 90 per cent of the Antarctic coast.