Excerpt from the Crystal Desert: Penguins (8)

I had the pleasure of spending time with David G Campbell during a cruise to the Antarctic. I love his book and will be posting excerpts from it from time to time.

The book is called “The Crystal Desert:  Summers in Antarctica” and is published by the Houghton Mifflin Company.

“A superior personal account of place, a remarkable evocation of a land at the bottom of the world (Boston Globe)

PENGUINS (8)

After a few weeks the nutritional need of the growing chicks cannot be met by parents who spend half their time ashore, and the chicks, which with a bit of luck and a lot of chutzpah are now big enough to fend off skuas themselves, are left ashore while both parents forage at sea. Without the warm shelter of their parent’s bodies, the chicks are vulnerable to exposure; the brown down of infancy soaks up moisture, and a freak summer shower or wet snowfall, followed by a freeze, can kill thousands. So the chicks instinctively cuddle. They form crèches: huddled groups of babies that anxiously await the return of their parents. There is safety in numbers, and crèches protect chicks in two ways: from the cold, by increasing body contact and presenting the least surface area to the elements, and from predation, by presenting skuas with a crowded and undulating mass instead of isolated and vulnerable individuals. Of course, the risk of exposure and predation is always greatest on the margin of the crèche, and those on the edge try to wedge into the warm center, pushing others to the outside. Perceived from a distance, a crèche seems to be a model of cooperation, with each animal taking its turn on the edge. In fact there is tremendous bullying for the favored spots on the interior. The bigger, first-hatched chicks invariably win, and the frontier of the crèche is littered with foundering chicks that haven’t kept up with the voracious pace of summer’s feeding. Some are runts that simply hatched late; others have been orphaned by leopard seals. Over the days, they slowly decline, and the difference in size and energy between them and the others widens. Toward the end, the skuas set up a vigil on the panting, flailing chicks, waiting for their little, cold deaths.

creches

The problem of recognition among family members is made yet more difficult by the babel of the crèches. How is a returning adult to recognize its own offering and not squander its bounty on an unrelated chick? Experiments have shown that the adults, however strongly bonded to each other’s calls, do not easily recognize the voices of their own chicks. However, the chicks by now have learned to recognize their parents’ vocalizations. Upon hearing an adult return from sea, they dash from the crèche – rotund, tripping tumbleweeds of brown feathers – to intercept. Sometimes three of four chicks will mob a big-gulleted adult, and in confusion it flees. But the chicks pursue, scrambling after it over the beach and through the abandoned nests. A particularly large chick can knock an adult down. Each chick is screaming, “You’re my parent, feed me!” But, of course, some are lying. There is enormous potential for parasitism here: to cop a meal from somebody else’s parent could assure survival. In the end, the most persistent chicks win and receive a ration of krill paste. The system is hardly fail-safe, but the chances are that an adult’s own chicks, so fervently imprinted on the particular characteristics of its vocalizations, will persevere.

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