The Flight of the Iguana

by David Quammen

  Curiously, this commitment seems to derive straight from the two other characteristics that we humans most admire in them: their noble size and their impressive migrations.

  Of the world’s fifteen species of wild geese, all are confined to the northern hemisphere, and most populations of those species make formidable annual migrations (hundreds or thousands of miles and, in one species, over the Himalayas), traveling northward in spring to breed, south again in the fall. Many fly all the way to the Arctic. Canada geese (also known as Canadian honkers and, scientifically, Branta canadensis) are the largest and the most familiar on this continent, with populations that follow flyways on the East Coast and the West Coast and several other north-south routes in between. The particular population I happen to know spend their winters in Arizona and thereabouts, feeding busily to build up fat reserves that will be needed later, and then fly up the Rockies to a certain braided stretch of the Madison River here in Montana, where dozens of tiny islands separated by narrow channels give them a choice of ideal nesting sites. As with any animal migration, there are routine costs and acute dangers that must be faced by these journeying geese. Why the various populations migrate at all is not completely explicable, but flying up into the far northern summer does bring them to fresh food supplies (they eat grasses and other vegetation), to areas relatively empty of man and other predators, and to thawing wetlands that suit their needs for nesting. Also, the type of food they find by chasing spring northward is especially nutritious, since the young plant shoots they favor tend to hold high concentrations of protein and nitrogen. This last fact is quite important. Nutritionally, geese have to play every angle they can.

  Their digestive system is damnably inefficient. Unlike other grazing herbivores, geese have no capacity to digest cellulose, which accounts for a large portion of plant tissue and holds the cellular juices (rich in sugar and protein) locked within cell walls. Most grazing animals digest cellulose with the help of bacteria that live in their guts. Along the upper digestive tract of a cow, for instance, is an extra stomach known as the rumen, wherein reside the cellulose-gobbling bacteria. But a Hereford is not obliged to cope with the delicate physics of flight. A goose, already large and heavy for a bird, and destined for long-distance flights, cannot tolerate the extra weight of a rumen. So a goose has no bacteria to help it with cellulose, and therefore no high rate of gastric efficiency. Much of the potential nutriment consumed passes straight through the bird without being utilized.

  And it passes quickly. A huge full belly is also forbidden by aerodynamics, and so the whole alimentary process is accelerated. A meal of grass travels the length of a goose gut, top to bottom, in only about two hours. During such a short time, and with no chemical breakdown of cellulose, digestion is necessarily partial. In consequence, a goose needs to be constantly filling itself and, also constantly, emptying. Hence the expression “Loose as a goose.”

  Concerning the storage of fat reserves, it’s the same problem once more. Some smaller birds that migrate to the Arctic can lay on as much as another full body weight before they head north to breed. But the laws of scale as applied to aerodynamics make that sort of provident fattening, for a goose, impossible. Already so large, a goose (despite its great strength) cannot let itself get much bulkier. Anything more than a twenty-five percent weight gain, during the winter months of serious feeding, will jeopardize its ability to get airborne.

  Each of these limitations makes the life of a goose a little harder, the margin of survival a little slimmer. Combined, they dictate that a goose needs to spend every possible moment stuffing its gullet. Hours are precious, net benefit is low, and a goose must gorge steadily just to stay even, or to get slightly ahead for those lean and costly breeding months to come. This may be, in fact, another reason why geese migrate north in summer: Under the long northern hours of daylight, they can spend more time feeding.

  And all those nutritional hardships of goosehood affect not just survival, but also procreation. A female goose will give away most of her own precious energy reserves—in the form of embryos and yolk—with the laying of a clutch of eggs. Then for almost a month she must incubate those eggs, scarcely leaving the nest to grab even one daily meal. During the incubation period she will regain some weight, but not much, since most of her time is spent sitting, supplying the motherly heat. Occasionally a female will even starve to death right on the nest. If she dies, the eggs will not hatch or the hatchlings will die also. The gander will be left a childless widower. Obviously, malnourishment of mama is bad for all concerned.

  But time spent courting, each year, would be time stolen from eating. Energy spent on sexual coquetry would be energy that might have gone into eggs, or made the difference for survival of a female exhausted after laying. Geese have neither time nor energy to spare, so they take a long view. They commit themselves to endurance, to each other, to the future—and not to maximizing their sexual options.

  • • •

  Romance in the life of a goose begins during the second or third winter. A male and a female find one another on the wintering grounds or just after migration north; overtures are made, a modest neck-stretching dance is performed, then reciprocated, and before long an understanding has been struck. This arrangement is accomplished almost hastily, but destined to last. The new pair honk in mutual acknowledgment, then fly off to establish a nest, which will be only their first of many. Ducks, closely related to geese in the family Anatidae, go about things differently. Ducks tend toward elaborate courtship displays and garish plumage among the males, both of which serve toward distinguishing males of a given species from females, and males of one species from males of another, all to facilitate the pairing process, which in ducks is repeated each year. Not the geese. Choosing one mate for life and remaining (with rare exceptions) faithful, geese have no need for such fancy displays or flashy dimorphic costumes. They put their resources to other uses. They spurn narcissism and fickleness and that annual flirtatious skirmishing, in favor of economy and a dignified singlemindedness.

  It takes the best efforts of two geese, working full time, to hatch and rear a brood of goslings. The female lays a clutch of eggs (five is the average number), and then sits on them throughout the chilling days and nights of April and early May. The male meanwhile stands watch. If a predator approaches, he warns her by honking, and together they fly to safety—or else she hunkers low on the nest and he takes flight alone, noisily, attempting to lead the danger away. After hatching, he is still there, standing sentinel so that the mother and young can devote their undivided attention to feeding—and now he loses weight, while his mate restores herself and the goslings grow. For two months the goslings are flightless, but good swimmers, and during that period they all travel their river or lake as a tight family group, the mother paddling in front, then a file of goslings, the father following close behind. In autumn they fly south again, still together, an inseparable family. Evidently the migration routes are not programmed instinctively, but must be taught by the parents to each new generation. On the winter feeding grounds they still stay together, with the father again mainly responsible for keeping watch while the others feed. Finally, after a full year, either the youngsters leave voluntarily or the male drives them away. He and his mate are now once again devoting themselves to each other, and to the prospect of a new brood. They fly north as a pair of old lovers, to Manitoba or British Columbia or Newfoundland, or to the channels of the Madison River in Montana.

  • • •

  Each year in May I take a boat down through the Madison channels and visit, as unobtrusively as possible, those nesting geese. In good years, when deadlines are distant and life is sane, I get down there more than once, catching the geese at various stages of their cycle. The first time I ever saw a brood of newborn goslings was also the first year I made the float in a kayak.

  There were two of us, a woman and I, neither of us very familiar with kayak technique nor with each other. As we paddled past a
small island, five balls of yellow fluff exploded hysterically out of a nest, straight into the river, and were swept immediately downstream. In the shock of the moment my friend’s kayak went upside down; I was no help whatsoever, and it seemed suddenly that five young geese and a tall twenty-eight-year-old woman might all drown at once. But everyone survived. Now the woman and I are married and at least some of those five goslings, with decent luck, have long since flown back up in spring to become grandparents. The years intervening passed very quickly.

  Monogamy and lifelong devotion, like an annual flight to the Arctic and back, are not things accomplished easily. St. Paul told the Corinthians that “love does not come to an end,” but the divorce rate among your friends and mine proves that St. Paul was either a liar or a fool. Considering all trends and pressures to the contrary, I was glad to find an ecological mandate for permanent partnership among animals so estimable as Branta canadensis. I was equally glad, recently, to come upon an interesting quote from the French novelist Marguerite Duras:

  Fidelity, enforced and unto death, is the price you pay for the kind of love you never want to give up, for someone you want to hold forever, tighter and tighter, whether he’s close or far away, someone who becomes dearer to you the more you’ve sacrificed for his sake. This sacrificial relationship is precisely the one that exists in the Christian church between pain and absolution. It can survive outside the church, but it retains its ecclesiastical form. There can be no more violent, and beautiful, strategy than this for seizing time, for restoring eternity to life.

  Geese figured it out for themselves. They know something about violence and beauty and time. Listen: uh-whongk, uh-whongk, uh-whongk, uh-whongk, uh-whongk . . .

  SWAMP ODYSSEY

  A Journey in Black Water and Time

  My eighteenth high school reunion was held in the Okefenokee Swamp, seven hundred miles from the scene of the crime. One advantage of this arrangement was that only two of us showed up. There was the Red Ace and myself. He flew into Jacksonville on a sardine-class ticket aboard People Express and spent a miserable night on a bench at the airport, worst sleep he’d had since May of 1966 when we pulled a late one cramming Virgil together for a senior exam and he crashed until morning in my bedroom chair. This was back before the invention of software, the pocket calculator, possibly also fire. People still memorized Latin verbs. The Red Ace and I, however, must have been the only two high school seniors of even our generation so moronically dutiful as to lose a night’s sleep over The Aeneid within ten days of graduation itself. More sensible souls were driving Chevies to the levee. All things considered, it was a miracle of Jesus that neither Red nor I ended up a priest or a lawyer. He went into professional tennis and I came out of grad school as a bartender and a fishing guide. Eighteen years later we rendezvoused at the Tahiti Motel in Folkston, Georgia, just outside the east entrance of the Okefenokee. Folkston, for those of you who remember Pogo, is not far from Fort Mudge.

  I had ridden out from Savannah with an old boy named John Crawford, a.k.a. Crawfish, a wizard swamp guide who by a happy coincidence of compatibility was just six days younger than the Red Ace and had therefore gone to high school together with us separately in a different place at the same time, if you see what I mean. We’re talking about the infamous mid-sixties, exactly those years stretching from “Louie, Louie” to the Gulf of Tonkin to the assassination of Malcolm X. Unmatchable for sheer dizziness and an overabundance of loud, nasty sounds. I had suggested the Okefenokee Swamp with a mind to peace and quiet. Also, I suspected it might be a wonderful place to visit.

  This cheerful predisposition was based mainly on optimism and ignorance. Turned out I was right, but for all the wrong reasons.

  I had imagined that five days of slogging across the Okefenokee Swamp would offer such heights of discomfort and travail that the experience would be exhilarating for its pure intensity. Tangled vegetation, oppressive heat, no solid ground for miles, fetid water, biting insects, ten thousand alligators, and the continent’s foremost selection of poisonous snakes—that sort of thing. I had put it to Red like one of those old recruiting ads for the Peace Corps: “Bad pay and long hours, but at least you’ll be hungry and in danger.” The experts said that you should do your traveling in this swamp, if you had to do any, between February and April—that is, before the water dropped, the heat came up, and the mosquitoes appeared in sky-darkening multitudes. So of course I had us there at the end of May. Even Crawfish, who himself harbors a helpless and unstinting love for the Okefenokee, had told me by phone, “You know, this trip is liable to be hardship duty.”

  Our last stop in civilization was at a tourist concession on the very fringe of the swamp, a store and boat dock run by a third-generation swamper named Harry Johnson, from whom the Red Ace made last-minute purchases (our eight or ninth bottle of insect repellent) while Crawfish saw to food and I filled a five-gallon carboy with drinking water. At least I had been told we would drink it. But the water that came out of Harry Johnson’s side tap was black, blacker than the coffee at the Folkston cafe. Johnson’s dock sat on a blackwater cove at the end of a blackwater canal leading away into the depths of the swamp, and the faucet was evidently drawing on that selfsame blackness. Also, the stuff smelled like a shoe factory.

  “Are we going to drink this?” I asked Crawfish, sloshing a bit out so he could see. Crawfish did not seem concerned.

  “Isn’t that a bit darker than usual?” he said to Harry Johnson.

  Harry Johnson smiled benignly. “Got a little sulfur in there. Do you good. Keep the ’skeeters off you.”

  • • •

  The Okefenokee Swamp is a great shallow saucer full of water and peat and vegetation, covering 400,000 acres near the eastern end of the border between Georgia and Florida. Thanks to a foresightful purchase by the U.S. government back in 1937, most of it is protected as the Okefenokee National Wildlife Refuge. It is closer to wilderness condition today than it was during the early decades of this century, when humans lived in it, hunting and fishing and timbering. Motorized travel is now restricted to the fringes of the swamp, and even canoe travel is controlled by the U.S. Fish and Wildlife Service, which grants a limited number of permits each year for the watery trails that lead to a limited number of campsites.

  The Okefenokee is a relatively young ecological system, the wild vegetal growth and the buildup of peat (dead and decaying plant material) having begun about seven thousand years ago. The swamp holds a very large volume of water that is very gently in motion. Prevented from percolating downward by impermeable clays underneath, and slowed by the sponge-like peat and the network of living vegetation, the swamp water flows down an incline that varies by only ten feet of vertical drop from the northeastern edge of the swamp to the southwestern edge. It is drained away by two separate rivers headed toward two separate seas: the St. Marys River, emptying from the swamp’s southeastern corner into the Atlantic, and the Suwanee River, meandering off from the western border of the swamp to the Gulf of Mexico. Within the swamp the divide between St. Marys flow and Suwanee flow is by no means clear cut, though a much larger share of the total finds its way into the Suwanee. The current of the Okefenokee itself moves in broad, shallow sheets more than in narrow channels, especially during times of high water, passing over and under and through the vast, filtering mass of vegetation and peat. For a number of complicated reasons related to ground-water seepage and the configurations of islands and troughs, as well as to the general incline, this current proceeds in a roughly circular pattern: a great mandala of dark water, moving around counterclockwise.

  The submerged vegetation and peat strain out organic impurities, while also turning the water black with tannic acid. It’s the same process that gives color to certain flatland jungle streams, like the Zabalo of eastern Ecuador or, most notably, the Rio Negro of Brazil. Plant life is burgeoning and dying within the drainage much faster than it can decay, much faster than the drowsy current can carry its products of decompos
ition away.

  The result is an acidic blackwater tea, ideal medium for culturing cypress trees, carnivorous plants, alligators. On a bright day that blackwater tea casts back reflections of a complete swamp world seen upside down, as on a surface of polished and oiled ebony. And it’s as potable, I learned eventually, as it is beautiful.

  • • •

  We set off from a point called Kingfisher Landing, the Red Ace and I paddling one canoe, Crawfish standing in the stern of the other, easing his boat along with what seemed to be effortless strokes of a twelve-foot bamboo pole. For an hour or three we moved down long tunnel-like corridors through thick brush, riding the current in a channel that was often no deeper than a bathtub and no wider than a sidewalk. In some places the brush arched overhead into a darkening canopy. In others it closed so tightly ahead that we had to spread branches by hand as we went through. Always the water beneath us was that lovely, inscrutable black. Crawfish led one detour to what he said was a typical gator hole—a small, muddy pond not far off our channel that had been scooped out of the peat by force of reptilian will. It was deeper than we could measure, more turbid than the channel, but apparently unoccupied. Crawfish probed his pole down into the center and made some strange muted yelping sounds into the end, like a drunken jazzman struggling with a clogged trumpet.

  “That’s it. Our guide has flipped. He thinks he’s a sea lion,” said the Red Ace. “We’re doomed.”

  “Sometimes that brings them up,” said Crawfish.