Scientists p-p-pick out penguins from space for new head count

Emperor penguins, lots and lots of them – and now we know just how many. Antarctica contains more than half a million – nearly double the number previously thought, a satellite survey has revealed. In the first comprehensive census of a species taken from space, high-resolution photos of 44 colonies around the Antarctic continent showed there were 595,000 birds – the previous estimate was 350,000.

Emperor penguins, pictured near the Halley Research Station, and seen from satellites breed in areas which have been hitherto very difficult to study because they are remote and often inaccessible with temperatures as low as -50°C (-58F). But the 4ft penguins, with black and white plumage, stand out against the ice and snow and colonies are visible on satellite imagery.

Scientists led by British Antartic Survey described in the journal PLoS ONE this week the "pan-sharpening" technique they used to boost image resolution to differentiate between birds and ice. Dr Phil Trathan at BAS said: "An accurate census that can be easily repeated will help us monitor more accurately the impacts of future change on this species."

Photographs by British Antarctic Survey