Scientists spy on penguins from space
Scientists have used satellite technology to discover thousands of emperor penguins in Antarctica by mapping the guano stains left by the birds on the ice.Accurate estimates of the numbers of emperor penguins have been hard to gauge because the birds spend most of the year at sea, only returning to the sea ice to breed in the winter when temperatures drop to -50 degrees celsius, making it difficult for scientists to observe them.
The stability of the penguins’ population is considered an important indicator of climate change because of their dependence on sea ice.
The birds, which are the least common Antarctic penguins, are also too small to be spotted directly by satellite imaging but researchers at the British Antarctic Survey realised that the birds’ guano was visible as reddish-brown patches on the ice.
By studying high-res satellite images of the continent, researchers located 38 colonies including 10 that hadn’t been spotted before – each made up of thousands of birds.
“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,” said BAS Mapping expert Peter Fretwell.
Penguin ecologist Phil Trathan said the next step in the research would be to count the number of penguins in each colony in order to monitor population changes over time. There are currently estimated to be around 200,000 breeding pairs in Antarctica.