Unhappy feet - Why do the chicks in this massive penguin colony keep drowning?
After rough seas have caused thousands of its chicks to drown, the second largest colony of emperor penguins in the world appears to now be collapsing.
The breeding ground at Halley Bay collapsed in 2016 causing thousands of chicks to drown. Halley Bay was the breeding ground for 5-9% of the world's emperor penguin population, according to the British Antarctic Survey who reported this catastrophe. This percentage amounted to 15,000 to 24,000 adult breeding pairs.
In 2016 the ice shelf collapsed due to rough weather, repeating again in 2017 and 2018. The chicks which died had not yet developed the feathers needed to survive in the sea when the ice shelf collapsed. The penguins arrive at Halley Bay each April to breed. The site has to remain stable throughout the Southern Hemisphere's winter (which lasts until December) for the chicks to survive.
In 2018 only a few hundred turned up at Halley Bay site. The remaining colony appeared to move closer to the ice edge, and were largely scattered. It's hard to know for sure if these penguins were non-breeders or failed breeders. The good news however, is that part of the colony have moved, and not died out. A colony known as the Dawson-Lambton Glacier, which is 34 miles to the south from Halley Bay has significantly grown in pairs since the disaster. Researches have reported that since 2016 where the colony had 5,315 pairs, it had grown to 14,612 pairs in 2018. Although these numbers are lower than the Halley Bay, it suggests a significant number of these penguins have realised it is better to move sites than return to the dangerous site of Halley Bay.
Sea ice that before was stable and reliable, is now insupportable. The sea-ice that is now forming is not as strong as it once was. Emperor penguins are the tallest and heaviest penguin species and therefore need a sturdy and reliable patch of sea-ice to breed on. Storms that now occur in earlier months will cause the platforms to blow out early.
If computer modes which have been configured by researches are correct, we could lose anywhere between 50% and 70% of the emperor penguin species by the end of this century.
It appears that the biggest threat to emperor penguins are not leopard seals or killer whales, but actually a much bigger predator, global warming.