Emperor penguins at the Halley Bay colony in the Weddell Sea have failed to raise chicks for the last three years, scientists have discovered.
Researchers from British Antarctic Survey (BAS) studied very high resolution satellite imagery to reveal the unusual findings, published today (25 April 2019) in the journal Antarctic Science.
Until recently, the Halley Bay colony was the second largest in the world, with the number of breeding pairs varying each year between 14,000 – 25,000; around 5-9% of the global emperor penguin population.
The failure to raise chicks for three consecutive years is associated with changes in the local sea-ice conditions. Emperor penguins need stable sea-ice on which to breed, and this icy platform must last from April when the birds arrive, until December when their chicks fledge.
For the last 60 years the sea-ice conditions in the Halley Bay site have been stable and reliable. But in 2016, after a period of abnormally stormy weather, the sea-ice broke up in October, well before any emperor chicks would have fledged.
This pattern was repeated in 2017 and again in 2018 and led to the death of almost all the chicks at the site each season.
The colony at Halley Bay colony has now all but disappeared, whilst the nearby Dawson Lambton colony has markedly increased in size, indicating that many of the adult emperors have moved there, seeking better breeding grounds as environmental conditions have changed.