Penguins on the move in a warming world
No animal is more iconic of Antarctica than the penguin, but now there is evidence global warming is forcing some colonies to move.
Mount Siple stands alone in one of the most remote parts of West Antarctica. It’s one of the continent’s largest volcanoes, rising 3,110 metres from a normally frozen sea.
Very few people, let alone scientists, visit this part of Antarctica but owing to poor weather and persistent pack ice to the northeast, our planned voyage is diverted here.
Using the expedition’s two helicopters, a team of researchers are flown to a headland on the edge of the mountain where there’s an Adele penguin colony.
Less than one percent of Antarctica is ice free, making a rookery like this a piece of prime land for nesting birds.
From the air it’s an extraordinary site, with tens of thousands of penguin chicks clustered together on the rocks.
There are tens of thousands more adult birds walking in ant-like lines along the edges of the ice cliff, arriving or leaving the colony from one of a few places where they can access the sea.
It’s late in the summer and the chicks are now old enough to look after themselves while their parents catch fish and krill at sea, then return to feel them.
This dependence means the chick’s parents are still much in demand, sometimes from their own offspring, but frequently from other hungry chicks hoping for a feed.
They chase the adults, flapping their short, ineffective wings. Many are in the process of losing their baby-feathers, giving them a shabby, rough appearance.
Surveying colonies’ populations like this one give researchers an idea of the health of the surrounding ecosystem.
“The nice thing about penguins and other seabirds is they give you this sort of canary in the coal mine indication of what’s happening in the Southern Ocean,” Peter Ryan of the University of Cape Town tells me as he bounds around the colony snapping hundreds of high-resolution photographs.
Later he will examine these to get an accurate idea of the size of the colony, but initially it appears this colony is thriving.
In other parts of Antarctica – especially on the Antarctic Peninsula on the west of the continent – penguin populations are not so constant.
These areas are warming faster than any other place on the planet, and as this happens scientists have noticed that colonies of Adele penguins are moving south down the peninsula. It’s believed they may be in search of colder conditions, but “We’ve got indicators of change in terms of temperature measurements, ice recession and the movement of birds to different habitats,” David Walton, Chief Scientist of the Antarctic Circumnavigation Expedition tells me.
All of which suggest to us that change is going in one particular direction; the peninsula is getting warmer; the ice is getting less; and some of the more sensitive species are having a harder time.”
In the coming weeks the new chicks will join their parents on the journey along the ice cliffs.
Having lost their baby-feathers and strengthened their wings, they will be ready to take to the ocean.
This colony on the edge of Mount Siple appears to be thriving, but it’s not clear whether this year’s brood will always return to this site, or whether our warming climate will force them to find a new place to nest.