Freely available satellite radar imaging is being used for the first time to help track colonies of endangered emperor penguins in Antarctica throughout the winter months.

Typically satellite images need sunlight to be useful, and Antarctica is dark in the winter. This has meant that colonies have been hidden at a critical time in the emperor penguin breeding cycle, when eggs are laid, chicks hatch and adults take part in those iconic huddles.

Almost 70 colonies of emperor penguins, many of which have never been visited by humans, occupy the sea ice that is fastened to the coastline surrounding Antarctica.

Now using synthetic aperture radar (SAR), an instrument operating on satellites that sends microwave pulses down to Earth, and measures how those pulses return, our research team has been able to track what the penguins do during these months.

Unlike other forms of satellite imagery, SAR is not reliant on sunlight, or affected by cloud, and therefore provides radar imagery of Antarctica through the dark........

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