It may be the king of the species but the personal hygiene of emperor penguins is far from regal. Vast expanses of penguin droppings that are visible from space are helping scientists pinpoint the whereabouts of penguin colonies in Antarctica.

Using satellite images, British scientists were able to locate penguin communities by the reddish brown patches, known as guano, left by the birds on the sea ice. They say the results of the study will help them to monitor the emperor penguin population in the face of climate change.

Emperors, which have white bellies, black backs and distinctive golden ear patches, are the largest members of the penguin family. They can grow to 122cm (4ft) tall and weigh around 30kg (5st) as adults.

“The ice gets pretty dirty and it's the guano stains that we can see,” said Peter Fretwell of the British Antarctic Survey (BAS), who led the study.

The study, which is published today in the journal Global Ecology and Biogeology, describes how the scientists located 38 colonies on the satellite images, of which ten had never been recorded before.

The scientists were also able to map more precisely the coordinates of colonies that had been spotted by people exploring the Antarctic coast by ship or helicopter.

In some instances, known colony locations had shifted slightly, due to the drift of sea ice. One colony had relocated entirely because their original home, on the Antarctic Peninsula, had melted.

The next step for the BAS team will be to acquire high resolution satellite images of the relevant locations. This will allow the scientists to count the number of penguins in each colony and keep track of any decline in numbers. “Using satellite images combined with counts of penguin numbers puts us in a much better position to monitor future population changes over time,” said Phil Trathan, a BAS penguin ecologist.

Emperor penguins spend the summer months of each year at sea. But in the winter when the water drops below minus 50C, the birds return to colonies to breed on the sea ice.

Emperor penguins are one of the species believed to be most at risk from climate change. An extensive study of one colony carried out by a French team in 2007 predicted a decline in population of more than 95 per cent by the end of the century.

Emperors breed the farthest south of all penguin species. In order that the chicks can fledge in late spring and early summer, the penguins breed in the dark, bitterly cold winter months, when temperatures plummet and wind speeds reach 200km/h.

The female lays a single egg in May and then passes it to her mate to incubate while she goes to sea to feed. For nine weeks the male penguins fast — losing up to 45 per cent of their body weight — while balancing the eggs on their feet to keep them warm. The female returns in August, around the time that the chicks hatch.

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