For the Adélie penguins on Petrel Island in East Antarctica, this is a critical moment. It is early summer and adult birds are returning in their tens of thousands to breed.
If all goes well, the island should soon be abuzz with the squawks of raucous chicks calling for food. Taking turns to waddle and slide across the ice, their parents fetch fish and krill to feed their hungry young. In the normal course of events, it is much as you would expect from watching Happy Feet.
But a far from happy scene greeted French scientists visiting to count the new arrivals last season. The bodies of thousands of tiny, starved chicks were strewn across the ground, their downy plumage sodden. Also dotted across the stark, glacial landscape were numerous unhatched eggs. From a breeding colony of 18,000 pairs of Adélie penguins – a species described as a – just two chicks survived.
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In the past 50 years, this colony has only once before faced a similar catastrophe, in 2013. That was a “zero year” – with no surviving chicks – in which thick ice and freak weather thwarted the adults’ unflagging efforts to feed and care for their young. A third disaster would bolster suspicions that these are not coincidences, but evidence of something more sinister.
Ordinarily, the Adélie parents seek out large areas of open water in the sea ice, called polynyas, where they dive for food. We know that in 2013, few polynyas opened up because thick sea ice was pushing right up against the coast, forcing the adults to travel further.
Scientists studying the colony say the thick ice was formed by unusual sea currents in the region around Petrel Island, the result of a huge iceberg – as big as Luxembourg – and dumping vast quantities of fresh water into the sea.
More unusual still was the heavy rainfall. Antarctica is the coldest place on earth and is also a polar desert, typically without rain or wet snow. Yet 2013 was both wetter and warmer than normal, with rain heavy enough to kill off the young, vulnerable chicks.
Death on the ice
The scientists who documented the most recent failure, led by of France’s , are now trying to gauge whether the same problems befell last season’s brood. They will publish their analysis in a research paper soon.
Establishing the likely reasons for that catastrophe is critically important. If, as in 2013, warm and wet weather is to blame, that may well point to climate change as the culprit, with the unfortunate implication that there is more of this to come. What is less clear is whether thick sea ice – also present during the last breeding season – can be linked to rising temperatures. Certainly, , Mertz-style.
It is also true that as Antarctica heats up another problem is likely to predominate: its sea ice is predicted to eventually diminish in area and thin. Although thick ice may be a problem, too little sea ice will also pose problems for the penguins, as an optimal ice level is needed for plentiful food.
The recent breeding disasters are one reason conservationists heightened their pleas to protect East Antarctica, but that idea was rejected at last month’s meeting of the . Those conservationists will be watching Ropert-Coudert’s research and current events on Petrel Island carefully, as East Antarctica’s status is up for discussion again in 2018.
Designating the area as a marine park would serve two purposes. It would remove the possibility of further human pressures, such as commercial krill fishing, adding to the Adélie penguins’ woes. It would also allow for the creation of a scientific reference zone, giving researchers a more controlled environment to study the bird’s changing circumstances.
At the moment, the Petrel Island problem is a local one and hopefully this season will be better for the penguins there. In the near term, the wider outlook for the species is good: there are numerous Adélie colonies around the Antarctic, and many are growing. But the nagging fear is that long term that might not last, that our actions are threatening a remote and fragile ecosystem, and with it, one of earth’s most charismatic creatures.
Read more: Warming won’t give emperor penguins happy feet; When giant penguins roamed the tropics
