Penguin poo a big help to scientists


Climate change

Emperor penguins

Credit: NOAA

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Penguin poo stains, visible from space, have helped scientists locate emperor penguin breeding colonies in Antarctica.

Knowing the location of these colonies will provide a baseline for monitoring the penguins' response to environmental change.

In a new study, published this week in the journal Global Ecology and Biogeography, scientists from British Antarctic Survey (BAS) described how they used satellite images to survey the sea ice around 90 per cent of Antarctica's coast to search for emperor penguin colonies.

The survey identified a total of 38 colonies, ten of which were new. Of the previously known colonies in the area, 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, but the reddish-brown patches of poo (guano) on the ice, visible in satellite images, provided a reliable indication of their location.

"We can't see actual penguins on the satellite maps, because the resolution isn't good enough," said BAS Mapping expert Peter Fretwell. "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. Though they return to their colonies to breed on sea ice during the Antarctic winter, when temperatures drop to -50 degrees Celcius, this is a time when it is most difficult for scientists to monitor them.

"This is a very exciting development," said BAS penguin ecologist Phil Trathan. "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 to those in the French study, suggesting that emperor penguins may be at risk all around Antarctica.