A remote-controlled rover that looks like a pile of chick feathers with a chick’s head on top has successfully penetrated the defenses of a colony of Emperor Penguins on Antarctica, getting close to the penguins without stressing them.
We know a lot about Emperor Penguin breeding behavior from 5 decades of observations on the colony at Terre Adelie, one of the 45 breeding colonies that ring the continent. There adults have been electronically tagged for id and heart rate and other measurements. That colony gave us the movie March of the Penguins
Alone of all the penguins, the Emperor breeds on the sea ice during the Antarctic winter. As winter descends, each female lays her single egg, gives it to her mate, and leaves for a very long walk out to the edge of the sea ice, as much as 100 km away by then, where she forages for krill before walking back again, arriving two months later just in time for her egg to hatch. During those two months, each male brooded the egg his mate laid, stuffed into a feathery pouch just above his feet. When the female arrives she finds her now starving and very stiff mate in the huddle of males, and he transfers the egg to her and then in turn walks away to the distant ice edge to forage for krill, to return two months later.
Of course this has all occurred in weather as extreme as this planet offers – extreme cold, high winds, totally dark almost all the time. A single mistake – an egg unprotected for a minute, a parent lost or delayed, unexpected climate stress – and the breeding effort fails.
As the ice recedes with the spring melt, adults don’t have to walk so far to obtain krill, the chicks grow large enough to be left in huddling creches, and both parents forage for food for their growing chick. By the time fall arrives, the chick is large and agile enough to begin to forage on its own. If by chance it survives its first winter feeding at sea, it has a reasonable chance of making it to adulthood, breeding for the first time when it is about 15 years old.
Meanwhile, environmental stress plays its increasing role. In years with very cold conditions, the extent of the sea ice forces the adults to walk much further, and chick mortality is greater. In years with warmer winters the sea ice is less extensive, the krill feeding on the under-ice algae have less to feed on and the foraging penguins find less food, and again chick mortality is greater. In warm years, sea ice can also break up under the feet of the colony, and then most chicks are lost. Successful breeding is a delicate balance of sea-ice extent, size of krill schools, and parental condition.
So we know that Emperor Penguins grow large, live long, and breed late, with the lowest possible clutch size. Chick mortality is usually very high, around 50%, and the mortality of surviving fledged chicks through their first winter is often just as high.
Altogether a harsh and extraordinary existence.
What’s ahead? Winter sea ice will, over the next century, continue to recede around much of the Antarctic coast, in some places much more rapidly than others. Of the 45 colonies, probably ten will go extinct, seven on the ice of the Ross Sea will probably persist, and the rest will decline enough to be endangered, vulnerable to extinction. The models indicate 2/3 of the colonies will be less than 1/2 their current size.
Look ahead longer than a century, and few colonies remain. A bleak prospect. Clearly now is the time for enlightened conservation efforts.
Knowing how many birds there are is an essential first step. Colonies were photographed by satellite in 2009 using a variety of filters, identifying 45 – some never visited and others rarely seen. The current total population estimate is around 600,000 birds. Changes that occur in colony size and location will show up clearly in similar future surveys.
A penguin reserve – no fishing, no tourists – is the essential next step. The Ross Sea, where sea ice loss is expected to be least, is the obvious choice. It would provide a refuge, though even there colonies are expected to shrink. And of course there is resistance to protecting the Ross Sea from fishing, particularly from the Russians.
The third step? We’re back to the need to reduce global emissions of greenhouse gases, and this week the US and China have given us cause for at least some slim hope.
Now, adding even more detailed and reliable information to support effective conservation, the rover-chick has arrived. It has its own camera peeking out in the middle of its chest, and it can get close enough to adults to read their electronic ids and download physiological data. It creates little stress among the adults, unlike a human creeping into the colony to gather the data, and it can roll right into creches where it appears to be accepted. We’ll know more about the state of the penguins as global warming stresses increase.
Perhaps some of the colonies of Emperor Penguins will adapt to the loss of sea ice. Four colonies have apparently moved back onto the glacier ice shelf, well above sea level, as sea ice has receded. But they may not be able to adapt to diminishing schools of krill.
The other too-famous movie ostensibly about Emperor Penguins, ‘Happy Feet‘, includes concerns about the effects of global warming. Its solution? Humans and penguins dancing enthusiastically together as a call for action. Absurd and mindless fantasies are not helpful.
Emperor Penguins are a worthy icon for illustrating the stresses and effects of climate change and global warming. Their long-term survival is anything but certain, probably even unlikely, but they seem to intrigue us enough to care about them.
successfully conserving them conserves so much more of what we could lose.