A satellite image showing the mark left by emperor penguin guano in the Antarctic.
(Photograph: British Antarctic Survey)
Penguin poo viewed from space reveals new Antarctic colony locations
British Antarctic Survey finds 10 new emperor penguins colonies
using satellite images that show patches of guano
by Shiona Tregaskis
Mark of the penguins: New colonies of emperor penguins have been discovered in Antarctica after their faeces stains were tracked by satellite
Guardian News Service (June 2, 2009) — Stretches of excrement-stained ice that are so large they are visible from space have helped scientists to locate 10 newly discovered emperor penguin colonies in Antarctica.
Researchers at the British Antarctic Survey (BAS) have used satellite images, created to survey the sea ice around Antarctica’s coast, to identify emperor penguin colonies using the huge tell-tale reddish-brown patches the birds leave behind.
BAS mapping expert, Peter Fretwell, said it was a “fortuitous” discovery. He noticed that patches on the ice in a satellite image corresponded with a known colony. The images, which came from the Landsat Image Mosaic Of Antarctica (LIMA), compiled by Nasa, USGS, National Science Foundation (NSF) and BAS, provide a high-resolution satellite view of the Antarctic continent.
By studying the images, the scientists discovered that guano stains are reliable indicators of the birds’ presence. “We can’t see actual penguins on the satellite maps because the resolution isn’t good enough. But during the breeding season the birds stay at a colony for eight months. The ice gets pretty dirty and it’s the guano stains that we can see,” said Fretwell.
The study, published today in the journal Global Ecology and Biogeography, identified 10 new colonies – which are each made up of thousands of penguins – bringing the total number to 38.
Emperor penguins spend a considerable part of their lives at sea. During the Antarctic winter when temperatures can drop to -50°C they return to their colonies to breed. Fretwell said: “Traditionally we would have used helicopters to find them because colonies breed on sea ice – which means they can be anywhere on the coast of Antarctica. Our previous knowledge is patchy.”
Dr Phil Trathan, BAS penguin ecologist, said: “Now we know exactly where the penguins are, the next step will be to count each colony so we can get a much better picture of population size. Using satellite images combined with counts of penguin numbers puts us in a much better position to monitor future population changes over time.”
Emperor penguin populations are a useful climate change indicator due to the birds’ reliance on sea ice. They are the least common Antarctic penguin, with an estimated 200,000 breeding pairs.
For more information, visit www.guardian.co.uk/environment/2009/jun/02/wildlife-poles