For the first time, researchers have succeeded in continuously tracking the movements of emperor penguin colonies from space, even during the dark Antarctic winter. This is made possible by radar satellites, which require neither daylight nor a cloudless sky. The new method could significantly improve the monitoring of this species, which is threatened by climate change.
Emperor penguins spend a crucial part of their life cycle during the Antarctic polar night. They require stable sea ice attached to the coast for many months in order to breed and raise their chicks. It was precisely during this important phase that it had previously been particularly difficult to observe the colonies over a wide area.
Researchers at Durham University have now utilised freely available radar data from the European Sentinel-1 satellite. Unlike optical satellites, its Synthetic Aperture Radar emits its own microwave signals and can therefore observe even in complete darkness and through clouds.
In the radar images, the emperor penguins stand out clearly against the comparatively flat sea ice. This enabled the researchers to track the position and movement of entire colonies throughout the winter.
A look at three large colonies
The emperor penguin colonies at Atka Bay, Coulman Island and Cape Washington were studied between 2017 and 2024. The team also used optical imagery from Sentinel-2 and Landsat 8.
This revealed that, overall, the colonies move less during the winter than in the summer. The satellite images also made it possible to identify not only the birds themselves but also the traces they leave on the ice. These include areas of guano, which provide clues as to where a colony has previously been.
This new method could help to track changes in the colonies much more accurately in future. This is particularly important because emperor penguins are heavily dependent on stable sea ice. If the ice breaks up too early during the breeding season, entire cohorts of chicks may be lost.
The findings are summarised in the study ‘Year-round movement of emperor penguin colonies observed from space’, which was published on 2 September 2026 in *Communications Earth & Environment*. It shows that Sentinel-1 could be an important tool for the long-term monitoring of emperor penguins in future.
This means that the world’s largest penguins can be observed from space practically all year round, even in the middle of the Antarctic polar night.
Heiner Kubny, PolarJournal