Four Wings and a Prayer (21 page)

O
N CLEAR DAYS,
days without rain or significant cloud cover, monarchs start dropping out of the sky at around three in the afternoon. There’s plenty of sunlight left then for flying, but sun, for navigational purposes, and warmth, for thermoregulation, are only two of the factors that keep a monarch in the air. Another is wind—which way it’s blowing, if it’s blowing, and whether it’s moving horizontally or vertically in a reliable, exploitable way. In the late afternoon, as the earth cools and the thermals break up, monarchs lose their free ride. They drift down to the ground, flapping as they need to and adjusting their glide angles, sinking yet held aloft by their thin, rigid wings.

Our airplane, despite its superior aerodynamic design, had the disadvantage of weight. It, and we in it, were far heavier than the wind. Gravity was always a factor. We caught a small thermal, gained a few hundred feet, lost it again, dropped a few hundred feet, found another updraft, gained fewer feet than we had lost, found another thermal. From the moment we came off the tow and for the whole time we were flying, we were in the process of landing, moving closer and closer to the ground until David said we were getting to the point where we’d have to put down. From the air we could see the gliderport with its stable of aircraft and its tin-roofed hangar reflecting the midafternoon sun. David said we had to fly a left circuit, over and behind it, then approach from the southeast. The trick would be in catapulting the power lines, since the wind, as we got closer to the ground, was gusting unpredictably in a southwesterly direction. We could see it now, combing the trees, which were swaying. “Not ideal circumstances for your first glider landing,” David said flatly, plying the rudder.

Landing scared me in a way that flying hadn’t. I had gotten
used to the notion that air was a fluid. I understood, in a visceral way, the metaphor of swimming that David liked to use. “A monarch swims through the air,” he said, an image that I both understood and found comforting. But landing required a different metaphor, and since none seemed to be on offer, the hard and solid reality of the ground seemed even more solid and harder. We passed over the hangar, then banked near the road, turning toward the field. David pressed on the rudder again and the nose of the airplane made a steep angle to the ground, one that my internal protractor found terrifying.

“Here we go,” David said, and the glider began to accelerate, heading directly for the power lines. Too frightened to close my eyes, I saw the cables slip under the belly of the plane with what looked to be about two feet to spare as the wind buffeted us this way and that. I had seen monarchs tossed about like that, fighting to fly southwest as the wind pushed them to the east, till their bodies were moving eastward but their heads were aiming in the direction of Mexico, as if will alone would get them there. David held hard to the controls, wrestling the wind with his intelligence. It needed only to be a draw, and it was, as we came in over the runway and leveled off. Twenty feet, ten feet, one foot above the rutted tarmac, dropping with a thud as a group of air cadets ran out to catch us, holding on to the wings of the plane to pin it down before the wind could do it damage. We were down. David congratulated me. I thanked him. We popped open the canopy and climbed out and for the first time all day caught sight of a monarch butterfly flying at knee height, flapping energetically. Although it was facing southwest, it was moving southeast. Professor Gibo and I paused to watch
it struggle against the wind for a time, only to give up and park itself in the grass. “It was losing ground with respect to the overwintering sites,” he explained as we went into the airport office to sign up for another flight. “Natural selection has produced an insect that can detect that. So it went down to where it could control its flight. If you watch, you’ll see that happen a lot.”

A
S A BIOLOGIST,
David Gibo watched a lot. With his binoculars and his sailplane, he was an entomological voyeur. The problem was that watching, as an individual, wasn’t getting him the information he wanted. What he was getting on his own was too sketchy, too thin. Gibo was interested in the monarchs’ flight tactics—in how, specifically, they exploited the wind in order to find their way to Mexico and back. And he was interested in the vectors they used and the directions they flew in. He knew that though their general orientation as they moved overhead in Toronto was southwest, they did not fly in a straight line. Not that they wouldn’t if they could, but the wind did not offer such direct routes. And he knew that for them, flying was like sailing: it required tacks to be made to close the distance between where they were and where they wanted to be.

“You can only do certain things when moving through the air that will allow you to get to where you want to go,” he said the day after our excursion to Arthur, as we were walking from his office on the University of Toronto’s Erindale Campus out to the parking lot, which serves as his study site. “This is the limitation of physics, basically, because, as you know, you are in a fluid. And you are using your interaction with
this fluid to keep aloft. And if you’re going to take advantage of things like thermals to get a free ride and increase your potential energy so you have something to play with, then that means you’re going to have to have pretty darn complex tactics, because the way to get up is to circle this rising air, which is drifting downwind and probably not going in the direction you want it to go. And now you have to compensate for the displacement due to circling in a thermal, gaining altitude. The fact that wind increases as you go up, the fact that you swing clockwise as you go up—you’ve got all those things going on, and you have to decide which direction you’re going to fly in when you leave that thermal. That is a fascinating problem—what the monarchs are doing in northeast winds, in east winds, in southeast winds—and something I’d like other people to get dragged into.”

The Erindale Campus, where Professor Gibo taught was a small branch of the university in Mississauga, a suburb about half an hour outside the city. It was pleasant if undistinguished, with the look of a large suburban high school. Because many of the students commuted, parking lots dominated the grounds, circling the main academic building with a broad band of blacktop. Gibo walked over to his car and laid out his instruments on the trunk, using it as his lab table—a habit, I’d come to notice, common among field biologists. “Any fool can do science,” he said, taking stock of his kit: field glasses, wind gauge, thermometer, compass, logbook. “That’s why it’s so powerful.”

Gibo was a proponent of laypeople doing the looking, the measuring, and the recording essential to empirical science. “Every single comet was discovered by an amateur,” he said. “You want to know why? Because they’re the only ones
who have the time to stand out there, take pictures, and then go back a week later to see if anything has moved. People are smart. They can do this work.”

The work to which Gibo was referring was the campaign he had launched on the Internet to enlist people to collect data about the flight patterns of migratory butterflies. “However clever their flight tactics, however mysterious their method of navigation, everything has to resolve into a series of simple rules,” he told the volunteers. “Lots of rules, hierarchically arranged and nested sets of rules, but above all, simple rules. The tiny nervous systems of butterflies just aren’t capable of anything else.” The rules would be revealed, Gibo believed, if enough data could be collected and then analyzed.

To encourage this, Gibo had set up an extensive Web site that was part field-biology cram course and part public record book. Participants were asked to record, in a standardized format, the flight behavior of migrating butterflies, including their estimated altitude, the type of flight (flapping, gliding, soaring), the wind velocity, the ambient temperature, cloud type, and heading. They were also asked to note—that is, to interpret—the context of the observation. “Butterfly was apparently engaged in courting behavior with another
D. plexippus,”
Gibo himself observed from the parking lot on September 1, a day when half the sky was dotted with cumulus clouds and the ambient temperature rose in the half hour he was out there from 20 degrees celsius to 23.5. “The one being observed appeared to maneuver to keep in tandem to two hundred meters, then glided back down to disappear behind the South Building. Two more solitary
D. plexippus
were also seen. Butterfly started at three hundred meters and
soared level before gliding down to two hundred meters. Its descent was gradual. A gull was also seen in field of view. Butterfly flapped upward. A second, lower
D. plexippus
flew past. Two more
D. plexippus
were seen. One glided down to a group of trees, one was flapping SW at five meters.”

Two weeks later a glider pilot in Worcester, Massachusetts, added his observations to the record, noting that during a routine flight at midday on September 16 he had encountered two monarchs at about forty-five hundred feet, soaring in a thermal that was also host to some fifty hawks. Again, cumulus clouds were scattered across the sky—often a good indication of thermal activity—and the wind was moderate. The thing that most intrigued David Gibo about this report was a detail that he posted as an addendum: the butterflies had been about sixty miles inland, and with the wind drifting in a southeasterly direction, they’d been moving with some dispatch toward the Rhode Island Sound and the Atlantic Ocean. By simply circling in thermals, Gibo surmised, they’d reach the water in just over four hours. If they spent half their time circling and half moving straight ahead by flapping and soaring, they’d get there about an hour earlier. Once they got there, Gibo said, “they would probably continue roughly southwest, paralleling the coast, pass through Cape May, New Jersey, and [maybe] even be counted by [Lincoln Brower’s associate] Dick Walton at the Cape May Bird Observatory.”

This, of course, was speculation. There was no way for anyone to know where these particular butterflies were going to go, or where they were going to end up. Gibo was making an educated guess based on what he knew about wind speed and cloud formation and monarch butterfly navigation. To me it was a story, but a compelling one based on some real
things, the way certain literary nonfiction both is and is not true. To David Gibo, though, the story was the essence of a certain kind of scientific enterprise, wherein the weight of reality—the mass of observed phenomena—allowed the creation of hypotheses (stories themselves) whose usefulness, if not their truthfulness, could be tested against the further accumulation of data.

“Most of science takes place in people’s heads, and then you present an argument to convince people and of course you arrange your argument in a way to make it maximally convincing,” he said. To me it sounded remarkably like plotting a novel.

O
UTSIDE IN
the Erindale parking lot, the sky was conspicuously free of bug life, at least at an observable level—a result, perhaps, of the wind, which was gusting. We were looking straight up, heads bent back as far as they could go, and nothing, nothing, nothing was in our line of sight, and then a kestrel. “This bird is gliding, by the way, it’s not soaring, and it’s going between thermals,” David said. “It just picked up a thermal,” he reported a minute later. “See it circling? See the circle? It’s going in a circle and gaining altitude.”

“When we were up there circling, we were playing,” I said. “When nonmigratory birds ascend in thermals, are they playing?”

“I doubt it,” David said, keeping his eyes fixed overhead. “They’re looking for food, checking out their environment, being shoppers, watching for other individuals, displaying to their mates, keeping cool. Crows, yeah. Crows tease.”

On this day, though, the butterflies were teasing, having promised, by showing up in large numbers in years past in this part of the world in this part of August, that they would be here now.

“Despite all the observations you’ve made here over the years, empiricism seems no more precise than divination,” I said to David when still, half an hour later, not a single monarch had flown by. I was hot, my neck hurt, and my eyes were going blurry. I was ready to pack it in.

Gibo did not for a second loosen his posture. “We need more data,” he said. As if that would be enough. In the meantime, for him, the middle of the story was just as compelling as its end.

Chapter 9

A
T JUST ABOUT
the same time that the monarch spotted at forty-five hundred feet over Worcester, Massachusetts—the one David Gibo surmised was on its way to the Atlantic coast at Rhode Island—would have been in sight of Cape May, New Jersey, I was getting there myself. Cape May Point, a spit of land that looked from certain perspectives as if it were rudely elbowing the ocean, had long been a draw for birders, who gathered there in great numbers, especially in the fall, when the sheer numbers of migrating songbirds, raptors, and water fowl could darken the sky—or at least seem to. Nearly four hundred bird species had been identified there. The checklist I was carrying in the back pocket of my jeans listed 391 in all and noted that John James Audubon had spent time in the nearby swamps and marshes, executing some of his well-known bird studies. The
Cape May Migratory Bird Refuge was at the joint of the elbow, where the Atlantic Ocean and the Delaware Bay mingled. Farther inland, but not far from the water in any case, was the Cape May Bird Observatory, one of the most active ornithological education centers in the country. Walk along the trail to Higbee Beach, stop at Stone Harbor or the Seventh Street Sea Watch, and others would be stopped there too, eyes trained upward or fixed on a particular tree limb. Stroll down Beach Drive, the wide esplanade fronting the ocean, and among the sunbathers and kite fliers and fudge eaters, would be an uncommissioned army of birders, easily identifiable by the Leica Trinovids and Bausch & Lomb Elites hanging on neoprene straps around their necks—benign but expensive ordnance.