Yet another use for satellite imagery: locating penguin colonies based on their guano.

British Antarctic Survey researchers noticed that the telltale reddish-brown stains left by large groups of penguins were visible in coastal images of Antarctica produced by the Landsat Image Mosaic of Antarctica (LIMA).  After one stain was matched with the location of a known penguin colony, the researchers found that the stains were a reliable indicator of the birds’ presence.

BAS mapping expert Peter Frewell explained, “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.”

The new discoveries brings the total number of Emperor penguin colonies to 38. Researchers hope to combine the satellite images with counts of each colony to monitor changes in the population in response to climate change.