Scientists map penguins from space

Penguin poo (guano) stains, visible from space, have helped British scientists locate emperor penguin breeding colonies in Antarctica. Knowing their location provides a baseline for monitoring their response to environmental change.

In a new study, published this week in the journal Global Ecology and Biogeography, scientists from British Antarctic Survey, (BAS) describe how they used satellite images to survey the sea-ice around 90% of Antarctica's coast to search for emperor penguin colonies. The survey identified a total of 38. Ten of those were new. Of the previously known colonies six had re-located and six were not found.

Because emperor penguins breed on sea-ice during the Antarctic winter little is known about their colonies. Reddish brown patches of guano on the ice, visible in satellite images, provide a reliable indication of their location.

BAS Mapping expert Peter Fretwell explains:

"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."

Emperor penguins spend a large part of their lives at sea. During the Antarctic winter when temperatures drop to -50°C they return to their colonies to breed on sea-ice, but this is a time when it is most difficult for scientists to monitor them.

BAS Penguin ecologist Dr Phil Trathan says: "This is a very exciting development. 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."

This research builds on work by French scientists who extensively studied one colony and found the population was at significant risk from climate change. The six colonies not found in this study were at a similar latitude suggesting that emperor penguins may be at risk all around Antarctica.

Source : British Antarctic Survey