Albatross

In The Rhyme of the Ancient Mariner, a sailor was cursed for killing an albatross. Fortunately, there is no penalty for merely startling one.

In fact, I’m not sure which of us was more startled. I was half asleep at the helm, alone on deck a thousand miles from shore. The light was failing. (Twilight comes quickly to the tropics.) A long, greasy swell was running after days of storm. The wind had followed the storm and we were becalmed, watch on watch, drifting without steerageway for days.

Shorttailedalbatross_1And we rolled. We rolled gunnel to gunnel. It was the sort of motion that chafed your patience as surely as it chafed the running rigging, the sort of motion that threatened to snatch you from your feet the moment you weren’t mindful. The only wind was the apparent wind created as the mast accelerated through the roll and the empty mains’l filled with a report sharp as a deer rifle, then went slack again. There is no storm more trying to a sailor’s patience then a prolonged calm. But a dead calm is even more trying to an albatross.

The albatross are consummate sailors. They spend their lives on the wind. They are masters of dynamic soaring—sliding down the face of the wind, exchanging altitude for kinetic energy, then rising again to repeat the process endlessly, days at a time, week after week of endless flight across thousands of ocean miles. They are so at ease with the wind that they sleep on the wing.

They sometimes feed on carrion like vultures. Unlike vultures, albatross can’t rely on rising columns of heated air to support their flight. Thermals ashore are fueled by topographic features’ differing capacity to absorb, then radiate solar energy as heat. Heated air, of course, rises more rapidly. At sea, one wave is much like another. The ocean’s surface warms uniformly. The albatross use another mechanism to stay aloft.

The wind close to the ocean’s surface is slowed by friction. This effect, called wind shear, is restricted to a boundary layer of air above the ocean. The further removed from the surface, the less friction the wind feels, the more free it blows.

Albatross work to windward by exchanging speed for altitude—gliding across the face of the wind, gently descending, then turning upwind when they have lost enough altitude to enter the boundary layer where the speed of the wind slows. With a weaker headwind, they glide farther. Before they’ve exhausted all the energy gained in the descent—perhaps the length of a football field—they angle their long wings for maximum lift and rise again. They are such efficient gliders that a small net gain of energy remains to power the next cycle.

But they are crippled in a calm. They need the wind to survive, to fly, which is the same thing to an albatross.

Albatross on deckI must have looked a more inviting perch than the masthead. The albatross approached in a long, silent glide from astern and deftly landed on my head. My reaction was purely instinctual. I shouted and stood up. The bird’s wings enfolded me. An albatross’ wing span can exceed 11 feet but, like all birds, it’s bones are made mostly of air. It felt like I was being cudgelled with feathers.

An albatross isn’t very good at flying by flapping its wings. The same aerodynamic elegance that favors them in dynamic soaring hinders them in rising from the ground or, in this case, my head. I had, at first, no idea of what was happening to me. Darkness alternated with light in breathless silence and everywhere the soft warmth of feathers battered me. It was like the embrace of an angel that smelled disconcertingly of fish.

Another thing common to birds—they typically void their bowels when taking flight. It makes perfect sense from the bird’s perspective. Why carry unnecessary baggage when you have to do all the heavy lifting yourself? At the time I was less understanding.

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