Date: April 24, 2019
Source: British Antarctic Survey
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.
