Four emperor penguin colonies uncovered by British Antarctic Survey using satellite imagery
Four previously unknown emperor penguin breeding sites have been uncovered by scientists from the British Antarctic Survey using satellite images.
The changing sea ice conditions along Antarctica’s coastline have forced several colonies to go in search of more stable sea ice on which to breed, with some known to have moved 30-40km.
Among the colonies found was one in Halley Bay that it was thought had vanished, but which has been re-established 30km to the east near the MacDonald Ice Rumples, following the calving of the Brunt Ice Shelf.
It means there are now 66 known emperor penguin colonies.
Scientists look for the birds’ brown guano stains standing out against the ice and snow to identify emperor penguin breeding sites, which are generally remote and inhospitable.
The scientists from Madingley Road-based BAS compared imagery from the European Commission’s Copernicus Sentinel-2 satellite mission with high resolution images from the Maxar WorldView-3 satellite.
But the future for emperor penguin populations remains uncertain, with BAS researchers warning last year of the species’ catastrophic breeding failure due to sea ice loss.
Dr Peter Fretwell, of BAS, said: “These newly-identified locations fill in almost all the gaps in the known distribution of these iconic birds. All except one of these colonies are small with less than 1000 birds, so finding these new colonies makes little difference to the overall population size. In fact, it is overshadowed by the recently reported breeding failures due to the early and fast ice loss.”
Stable sea ice attached to the shore - known as ‘land-fast’ ice - is needed for most of the year by emperor penguins.
Arriving at their chosen breeding site, they lay eggs in the Antarctic winter from May to June which hatch after 65 days, although the chicks do not fledge until between December and January.
Out of 45 years of recording, four of the years with the lowest sea ice extents in the Antarctic have come since 2016. The two lowest were 2021-22 and 2022-23.
In August 2023, the sea ice extent was 2.2 million square kilometres lower than the 1981 – 2022 median - equivalent to an area larger than Greenland.
