"Two thousand feet," he confirmed. I pulled back on the k.n.o.b, which resisted for a moment, then gave way with a jerk and a loud pop that startled me. The yellow cord snapped away, and all the noise did, too. Quiet rushed in around us, a whispering quiet, and the plane untensed like a hand gone from fist to open palm, and for the first time since taking to the air we were flying, really flying, and it was, much to my surprise, glorious: serene, buoyant, unlikely, glorious. The air, which until then I think I had not seriously taken into account as a force in my life, was holding us up. I could feel it, as if it had especially large fingers that pressed into my flesh. Air was a fluid, David had told me earlier, and now, buoyed by it in a tangible way, I felt what he meant. He pushed gently on the right rudder pedal and we turned slightly, then rushed forward in a graceful swoop.

"The clouds are pretty fragmented," David said, referring to the thermal updrafts we were seeking. David's voice was calm and measured. He was a seasoned pilot. I figured if he was untroubled by the fragmentation, I should be, too. I leaned back in my seat and looked out the window. I could no longer say that I didn't like to fly.

A MONARCH TRAVELING to Mexico from where we were in southern Ontario would have to fly about two thousand miles to reach one of the overwintering sites, and it would take it ten or eight or six or fewer weeks to get there. Powered flight-flapping-would propel the bug forward, but at a cost in terms of both fuel consumption and time, since powered flight, despite its name, is relatively slow. When most people think of monarch b.u.t.terflies' migrating to Mexico, though, and then going back to the United States and Canada, that's the image they have in their heads-a small and fragile and vulnerable creature flapping like mad in a determined and enervating manner.

Up in the c.o.c.kpit of his Grob 103, David Gibo understood in an intimate and practical way that a b.u.t.terfly could not possibly flap its way to Mexico. Gibo could travel on the wind for hours in his fixed-wing airplane, soaring and gliding across the sky using thermal updrafts, or rising columns of warm air. The b.u.t.terflies, he reasoned, must do the same thing. Gliding (nonpowered flight in still air) and soaring (nonpowered flight in moving air, such as a thermal) were the methods that enabled both him, in his Grob, and a monarch, with its aerodynamic constraints, to travel long distances with little wear and tear and even less fuel consumption.

"Typical gliding and soaring flight, with the wings outstretched, [does] not generally require any effort from the insect," noted the German zoologist Werner Nachtigall in his book Insects in Flight. "No energy is expended, either because the wings themselves automatically take up the gliding position as soon as the flight muscles are relaxed ... or else [because] there is a 'click mechanism' which puts the wings into the right alt.i.tude mechanically. This latter method is how b.u.t.terflies a.s.sume a gliding mechanism."

It was in the same book that, shortly before heading up to Toronto to meet David Gibo, I had read this: "[A glider pilot] climbs steeply in one thermal, then leaves this and glides obliquely downwards towards the nearest thermal, in which he soars again, and so on. By this means he can make long, cross-country flights without having any engine. The only snag is that each time he must find another thermal before his downward glide has taken him to ground level. If he does not he must land."

Up above the farms of Wellington County we drifted with lazy purpose, circling laconically and moving in a direction that felt like up. I knew that some gliders could course the sky all day, and that some had reached alt.i.tudes that required supplemental oxygen. Our goal was to stay aloft as long as possible, which meant at best twenty or twenty-five minutes. I also knew that sometimes the thermals were so prevalent that it was hard to come down, though this was rare, and that most of the time pilots crossed the sky as if the thermals were stones in a stream-upwardly mobile stones that moved them both up and over at the same time. Lose the thermals, and you were on your way down.

"We're in sink!" David said from the backseat. His voice was steady, uninflected. My eyes fixed on the horizon, trying to see what he meant.

"What is 'sink'?" I asked, seeing nothing but wispy clouds and another glider, far enough away to look smaller than it was. David adjusted the rudder and the aileron. The nose of the plane, which was pointing downward, wiggled up.

"It means that we've lost the thermal and we're losing alt.i.tude," he said, but sounding calm and businesslike. Sink. It was a delightfully descriptive word. I knew I should feel scared, but I didn't. I checked the altimeter: we had dropped five hundred feet within a matter of seconds. Even so, we were already on our way to another thermal, banking sharply as we aimed for a destination in the sky that only David Gibo could make out. In less than a minute we had caught the updraft as if it were the 1:17 commuter train pulling out of the station.

"Usually what you do is fly a pattern in order to fly into a thermal," Gibo was saying. "Now, with the b.u.t.terfly, it goes in the direction it wants to go, finds the thermal, and then behaves appropriately."

I can't say I was listening attentively when Professor Gibo explained this, or when he mentioned that meteorologists had picked up migrating monarchs on radar, flying at five thousand feet. Instead I was thinking about the words We are in sink, and the fact that we had been falling from the sky and that the sky-invisible and elusive-had held us up.

ON 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 circ.u.mstances 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 pa.s.sed 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 b.u.t.terfly 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 gra.s.s. "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."

AS 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 alt.i.tude. 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 gla.s.ses, wind gauge, thermometer, compa.s.s, 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 b.u.t.terflies. "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 b.u.t.terflies just aren't capable of anything else." The rules would be revealed, Gibo believed, if enough data could be collected and then a.n.a.lyzed.

To encourage this, Gibo had set up an extensive Web site that was part field-biology cram course and part public record book. Partic.i.p.ants were asked to record, in a standardized format, the flight behavior of migrating b.u.t.terflies, including their estimated alt.i.tude, 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. "b.u.t.terfly 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 c.u.mulus 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. b.u.t.terfly 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. b.u.t.terfly 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, Ma.s.sachusetts, 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, c.u.mulus 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 b.u.t.terflies 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, pa.s.s through Cape May, New Jersey, and [maybe] even be counted by [Lincoln Brower's a.s.sociate] d.i.c.k Walton at the Cape May Bird Observatory."

This, of course, was speculation. There was no way for anyone to know where these particular b.u.t.terflies 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 b.u.t.terfly 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 ma.s.s of observed phenomena-allowed the creation of hypotheses (stories themselves) whose usefulness, if not their truthfulness, could be tested against the further acc.u.mulation 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.

OUTSIDE 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 alt.i.tude."

"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 b.u.t.terflies 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.

AT JUST ABOUT the same time that the monarch spotted at forty-five hundred feet over Worcester, Ma.s.sachusetts-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.

Lepidoptery is a lesser franchise on Cape May, but a growing one. There are 105 known b.u.t.terfly species on the cape, and its peninsular shape has made it a refuge for migrating monarchs. Birders looking for pa.s.sing hawks often picked them up in their spotting scopes, in numbers that made them seem like winged rain.

d.i.c.k Walton was one of these. The author of a number of books that were part of the ornithological canon, as well as a series of popular birding-by-ear instructional tapes, he had gone down to Cape May from his home in Concord, Ma.s.sachusetts, on October 10, 1982, to witness the legendary hawk migration. It did not disappoint. On that day 2,622 sharp-shinned hawks, 62 Cooper's hawks, 50 peregrines, and 130 merlins pa.s.sed overhead. But Walton was seeing something else as well, as he observed in his journal: "All day long we witnessed a phenomenal monarch migration. The b.u.t.terflies were as constant and continuous as the hawks." And it wasn't just that year. The pattern-hawks and monarchs migrating on the same wind-continued in subsequent years, piquing Walton's interest. d.i.c.k Walton is a free-lance natural historian and, though primarily a bird-watcher, he was not content simply to look at the b.u.t.terflies going by.

"In the fall of 1990 I decided to spend two weeks in Cape May with the idea of planning a long-term research project on monarch migration (what the heck-somebody has to do the work)," he recalled. "I tried out several census methodologies at various places on Cape May Point. At Sunset Beach on September 27, in eight one-minute observation periods, I counted 618 monarchs, for an average of 77 monarchs per minute. The following day I counted over a thousand monarchs streaming through Cape May Point State Park. Although there were plenty of monarchs, there were also many puzzles. One of my first discoveries, while counting monarchs at Cape May State Park, was that the direction of the migratory flight seemed to reverse itself for no apparent reason. At one point a steady stream of monarchs would be heading southwest and then within the s.p.a.ce of ten minutes, the whole flight would be going northeast. When I returned home I puzzled over the data, and even though there were more questions than answers, I was convinced Cape May would be an ideal site for my study. So I wrote Lincoln Brower that December and we began discussions about setting up the project."

The project, though billed as the Monarch Migration a.s.sociation of North America, was really just d.i.c.k Walton, an a.s.sistant, a car, and a hand-held, nonautomated counter. The idea was to establish a census route through Cape May that would be followed three times a day in order to begin ama.s.sing data on the numbers of monarchs migrating through Cape May each fall. While the figures for any one year would be interesting in and of themselves, it was the acc.u.mulation of data that would be most telling. "Good" years and "bad" years, "big" days and "small" ones-all would settle out, or become revealing, over time.

It was this data, eight years out, that brought me to Cape May on one particular day. Historically, September 19 was a big day there, a day on which in previous years thousands of monarchs had flooded the skies and cl.u.s.tered on the trees and nectared in the pocket parks. If the data were any guide, September 19 was the day to be in Cape May-especially, I reasoned, if the b.u.t.terflies seemed to be scarce elsewhere. Either they'd be here, and that would be significant, or they wouldn't, and that would be significant, too. It was win-win, though I'd rather prevail by witnessing a deluge of monarch b.u.t.terflies.

d.i.c.k WALTON MET ME at the hawk watch bench at Cape May Point. The bench is a raised platform bordered by railings, equidistant from a marsh (good for sighting waterfowl), the beach (good for sighting sh.o.r.ebirds), and the parking lot (good for sighting the latest in ornithological gear). Most days it fills early, as curious tourists and serious birders sit shoulder to shoulder looking into the sky. Even among these, d.i.c.k Walton was recognizable. Bearded, with a worn Red Sox cap on his head, sporting an ancient pair of binoculars, he looked like he belonged there.

"We do three census runs per day, at nine, twelve, and three o'clock," he told me. "They take fifteen minutes each. We note the date, the temperature, the cloud cover, the wind direction, and the wind speed, determined by leaf movement. It's pretty standard, and it's fairly subjective. Any observation is.

"On the census runs we're not trying to count all the monarch b.u.t.terflies in Cape May. We're taking a sample. If you sample along a route long enough, it will become more accurate. You might see thousands over at the hawk bench, and up on the dunes, but this is more accurate. There you're getting flight reversals. You're counting the same b.u.t.terflies more than once. They're deciding whether or not to cross Delaware Bay-it's eleven miles. We know they cross open water because we see them when we take the ferry. But the wind has to be right or they turn back, which is when you start to miscount. Our census spreads it out so we get a better idea of what's really going on. If you want to census dogs in New York City," he concluded, "you wouldn't want to go to a fire hydrant."

It was not quite nine in the morning. We drove out of the parking lot toward the Cape May Lighthouse, then turned up Lighthouse Avenue and headed for the Higbee Beach Wildlife Management Area on the bay side, where the census began. d.i.c.k pulled up to the parking lot, which was already full-it was a hot spot for birders-and then he turned around and consulted his watch. The census was due to begin on the hour. And it would have, if twenty people hadn't been stationed in the road, looking for a particular warbler in a particular tree. We eased out slowly, picking our way around them and then working up to a steady twenty-five miles an hour, the uniform census speed. Some days Walton was followed by another person in another car making her own, independent count, but not today. It was just the two of us, and the rule was that we were not to tell each other when we saw a monarch. We were not to twitch or make any sort of movement that might give it away. d.i.c.k Walton held his counter out the window on the left side. I held mine out the right. He didn't want either of us to influence the other.

"Most b.u.t.terflies disappear when it's cloudy," d.i.c.k said. He was driving one-handed, scanning the sides of the road, the middle distance, the sky, his eyes moving quicker than his car. "Once I was doing the census in a nor'easter and saw one blowing down the beach. It didn't want to be flying. I counted it." He turned onto Baysh.o.r.e Road, hugging the shoulder, letting the other cars pa.s.s.

"Sometimes I think I should have a banner so people know why I'm driving like this," he said.

I was concentrating on the farmland we were pa.s.sing, looking hard for monarchs and seeing none. I thought I had noticed d.i.c.k tapping his clicker, and I wondered if I had missed one, or more than one. It was making me anxious, tetchy.

"Did you know that Cape May is the lima bean capital of the world?" d.i.c.k asked as we pa.s.sed a processing plant called the Beanery. No, I didn't. "Seaside goldenrod is a good source of nectar," he said a minute later. I wondered if this was a clue and scanned the plants as we pa.s.sed by, but still I saw no monarchs.

We turned off Baysh.o.r.e and drove in the direction of the bay. So far the big day wasn't happening. Even my poker-faced driver seemed disappointed. "Negative data are good," he said, "but they're not much fun to collect." Maybe he hadn't seen any b.u.t.terflies after all. We drove past the light-house again. "We just need a little more brightness," he said, "but I don't think we'll get it on this run." Click. I heard his counter tally a b.u.t.terfly, just like punctuation. I looked around madly, didn't see a monarch, and left my counter registering a row of zeros. Now we were zigging and zagging through the residential neighborhood between Lily Lake and the sand dunes. It was seventy-three degrees and overcast. A monarch was crossing the road. "There, look!" I said, waving my hands excitedly. d.i.c.k Walton shot me a bemused look. So much for "double blind." I had given it away. I heard his counter click again.

It was 9:17 on the morning of the big day. Total number of monarchs sighted: two. We returned to the hawk watch bench, where d.i.c.k Walton gave me an impromptu lesson in identifying birds in the sky. There were thousands of tree swallows sailing about, with a big bird laboring among them.

"Tell me about that big bird," d.i.c.k Walton said. "What do you notice about it?"

"It's big," I said.

"It's an immature bald eagle," he said.

"Where?" said a chorus of voices. The hawk watchers turned from what they had been doing and searched for the eagle.

"This is great," said a portly man in shorts and a photographer's vest, sporting a Cape May Observatory hat on his head. "I didn't look at birds till I retired here," he said to me. "I used to think people who looked at birds were nerds. An immature bald eagle-haven't seen too many of those. Wish I had started doing this a long time ago."

d.i.c.k pointed above a stand of cedars. "Now there's a good bird," he said. Again, as if on point, the birders turned and tried to pick up what he was seeing. "Can you tell from the shape of the wing what it is?" he asked me. I couldn't.

"It's an osprey," he said. Another bird of prey. And there, at a hundred feet, was some prey, a lone monarch gliding in exactly the same direction the wind was blowing.

IN ADDITION TO creating a historical record of monarch b.u.t.terfly behavior at Cape May, Walton's Monarch Migration a.s.sociation of North America (MMANA) sought to do something else as well: to demonstrate, once and for all, that the movement of monarch b.u.t.terflies down the East Coast of the United States was not an aberration; to show, through numbers and constancy, that there was a real and established Atlantic flyway that led to the Mexican overwintering sites. This had been a matter of dispute for at least a decade, beginning with Lincoln Brower, then a professor at Florida, squaring off against-again-Fred and Norah Urquhart. It was the Urquharts' understanding, based on their tagging data, that monarchs found on the East Coast had drifted there unwittingly, the victims of winds that carried them southeast instead of southwest.

After the first four years of the Cape May census project, it looked as if the evidence would eventually prove the Urquharts wrong. As Brower and Walton wrote in the Journal of the Lepidopterists' Society after correlating their findings with data from the North American b.u.t.terfly a.s.sociation's annual Fourth of July b.u.t.terfly count, "During the four-year period of our study we have consistently recorded large numbers of monarchs at Cape May, New Jersey, [and] have also regularly observed migratory behaviors including 1) ma.s.s movements along beach and dune lines; 2) a high degree of directionality ...; 3) roost formations; and 4) significant build-ups and exoduses on consecutive days. Another notable characteristic has been the timing of the fall movement. In each of the four years studied, the numbers of migrants peaked during the third week of September." Therefore, they concluded, "our Cape May observations argue in favor of describing the Atlantic coast migrants as routine const.i.tuents in the monarch's fall migration. The numbers and behavior of monarchs observed leave little doubt that a significant migration has occurred at Cape May in each year of our censuses. Aspects of the timing of the migration, in particular the recurring September peaks, also indicate a routine pa.s.sage of monarchs. Such consistent timing would be unlikely if they were caused solely by weather conditions such as cold fronts, because the latter do not occur at the same time each year. Finally, the correspondence of the Cape May and 4JBC [Fourth of July b.u.t.terfly count] data sets suggests that the number of monarchs pa.s.sing through Cape May is representative of northeastern breeding populations as a whole. If this correlation holds in future years, it will strengthen the hypothesis that the Cape May migration is representative of the population of northeastern monarchs, rather than comprising an 'aberrant' group displaced by atypical weather conditions as hypothesized by the Urquharts."

Now, with four more years of research completed, Brower and Walton's conclusions still held. While the numbers of monarchs pa.s.sing through Cape May fluctuated from year to year, their presence was constant. Monarchs could be seen up in thermals with the migrating hawks and roosting in the trees around town. If in decades past their aggregations had been merely the subject of anecdote-the late Roger Tory Peterson, for one, "recalled from visits to Cape May in the early 1930s trees so completely covered with monarchs that they were 'more orange than green' "-the MMANA census data lent those observations weight. ("Those folks lucky enough to have been in the Cape May area on either September 19th or 26th were treated to a blizzard of monarchs," d.i.c.k Walton reported in his annual summary for 1997. "In fact, on the 26th, 652 monarchs were counted on the three census runs. This eclipsed all previous records for daily run totals. Observers at the [hawk bench], Higbee, Cape May Meadows and even along the streets of downtown Cape May reported hundreds, even thousands, of monarchs on both of these days.") But that was a year earlier. On this September 19, a casual observer would have been hard pressed to discern a migration at all. All day, it seemed, we were busy looking through our binoculars from the hawk bench, or inching our way down New England Avenue, collecting negative data.

And that day, it turned out, was not unusual. Throughout the 1998 migration season, d.i.c.k Walton and his a.s.sociates noted that the number of monarchs pa.s.sing through Cape May was less than half what it had been the previous year. Walton attributed the paucity to the Mexican drought and early storms in the northern breeding range. Still, he couldn't say for sure.

What he could say, though-finally and, at the end of 1998, conclusively-was that the Urquharts had been wrong. For the first time since 1992, when MMANA began tagging monarchs, b.u.t.terflies tagged at Cape May had been recovered in Mexico, at the El Rosario colony. And not just one or two-seven had been found there. But it got even better than that: four Cape May b.u.t.terflies had also been recaptured farther down the coast, in Virginia. The data were like those chemicals that reverse invisible ink: once they were applied, the Atlantic flyway that Lincoln Brower and d.i.c.k Walton had always a.s.sumed was there at last revealed itself.

AT SOME POINT, of course, the monarchs that flew down the eastern seaboard and then to Mexico had to swing inland. Maybe they turned in the Carolinas, or maybe they hugged the coast to the thumbnail of Florida, where, confronted with open water and its maniacal choice, ocean or gulf, they chose the gulf. Whatever their course, there was still no evidence to support either notion, just the tantalizing fact that some coastal monarchs found their way, somehow, to El Rosario.

"It's a real enigma, the flow of monarch b.u.t.terflies down the East Coast," Chip Taylor said to me again one day when I was visiting the Monarch Watch office in Lawrence. "Why do we have these big holes?" He pointed to the map of tagged monarch recoveries, the one that had no red pinpoints anywhere in the Southeast. "The longitudinal data are great, but the recoveries don't meet up with our expectations regarding lat.i.tude." He tapped the hole in the map with his pen. "The b.u.t.terflies ought to be turning right."

It was the Big Right Turn theory again, a conclusion the data merely hinted at. David Gibo had gone in search of its coordinates in his ultralight airplane and failed to find them. Chip Taylor had distributed hundreds of thousands of Monarch Watch tags, but none had ever shown up in Mexico from any southeastern state. Now he was on to something else. Or rather, his colleague Sandra Perez was. The year before she had taken Kansas b.u.t.terflies to Washington, D.C., and Dalton, Georgia, and released them to see which way they went; all had behaved as if they were in Kansas, flying southwesterly. Now she was going back to repeat the experiment, but with a difference: this time she was going to cage the monarchs in situ for a few days, on the theory that they might need a little time in their new neighborhoods to figure out how to read the local cues.

"I still expect them to behave the way they would if they were in Kansas and go southwest, but Chip expects them to adjust for their new orientation and fly more westerly," Perez said. More westerly would suggest the Big Right Turn.

As she talked, Perez took a quick inventory of the materials arrayed on the table in the biology annex, located on West Campus, in a trailer she shared with a postdoc who studied crickets: plastic hangers, toothbrush holders, duct tape, pieces of wood. Perez was making artificial nectar feeders for the b.u.t.terflies she planned to keep in captivity. For as long as they were with her, they'd be treated to a c.o.c.ktail of Gatorade and protein, served from a soaked, colored kitchen sponge. The feeders held the sponges.

"What I love about field biology is that I can get all my equipment at Wal-Mart," Perez said, bridging two hangers with a piece of wood that she then secured with a length of duct tape. That done, she taped the top of a toothbrush holder onto the wood. This would cradle the sponge.

"When the migrants come through I collect several hundred at a time," she said, tearing strips of tape and hanging them off the side of the table. "This many feeders is probably excessive, but I don't want anyone to be hungry in there." She motioned for me to start taping the wood to a hanger. Production swung into high gear.

"I'm sure one of the biological supply houses sells something like this premade," she said after a while, "but this is a lot cheaper. And a lot more fun."

BUT IF THE HANGERS, the toothbrush holders, the sponges, and even the tents where the captives would be housed could be bought at Wal-Mart, Perez was still missing the one thing she could not buy there: b.u.t.terflies. Specifically, nonreproductive migrating b.u.t.terflies. Migrants were as scarce in Lawrence that fall as they were in the Adirondacks and Toronto and Cape May. The Baker Wetlands, not far from the university campus, a reliable roost for migrating monarchs in years past, was now as empty as a condemned building. We saw just twenty of them in a quarter-mile stretch on which on an average day the year before we would have seen ten thousand. That order of magnitude could not be explained away. "They've never been this late before," Chip Taylor said of the monarchs. But he couldn't say where exactly they were, or where they'd be coming from.

He had a hunch, though. When you needed migrating monarchs in Kansas, there was one sure place to go: Wamego. There was a high school biology teacher there, Terry Callender, whose students had tagged more monarch b.u.t.terflies than any other group. One year, twenty or so kids had captured, measured, weighed, tagged, and released an unprecedented twelve thousand monarchs. They'd had a lot of recoveries, too. Terry's cla.s.sroom, Chip said, represented the best of what Monarch Watch had to offer students. If they had monarchs there, he was sure they would share. Sandra and I consulted a map. Wamego looked to be about two hours away, between Topeka and Manhattan, on Highway 24. We gathered nets, extension poles, envelopes, and high-beam flashlights. The high beams were key, Sandra explained, since we'd be jacklighting the b.u.t.terflies.

"Isn't that poaching?" I wondered aloud.

Sandra looked at me with amus.e.m.e.nt. "This is science," she said, laughing.

TERRY CALLENDER, an affable, bearish man with a neatly trimmed beard and gray hair, waved us into his cla.s.sroom in the bas.e.m.e.nt of Wamego High. It was the end of the day, and students were gathered by his desk waiting to sign out b.u.t.terfly nets while Callender, wearing a faded Monarch Watch T-shirt, teased them.

"If you want to get out of science process cla.s.s on Friday, bring in a thousand monarchs and we'll have too much to do to do anything else," he told them. They nodded earnestly.

Terry turned to us. "We usually do five or six hundred per cla.s.s. They get really efficient, especially if we shut down the cla.s.s. Sometimes a single student will bring in five hundred or even a thousand b.u.t.terflies. For some reason we always get a lot of monarchs here. It can get really wild. Two years ago we had eight hundred we had to feed because it was too cold for them to fly. Sometimes we get so many b.u.t.terflies that I don't teach the entire day and we just tag the whole time. It's like a factory. When school started this fall the kids came in and said, 'When do we get to tag?' I'd never heard that before. They are really into it."

On the wall over the sink in Terry's cla.s.sroom was this message: "I hear and I forget. I see and I remember. I do and I understand." One look around and it was obvious that nothing could better describe his educational philosophy. In a run-of-the-mill school in a rural midwestern backwater, Callender was pioneering the kind of hands-on, experiential learning favored by progressive educational reformers in more sophisticated places. There were waders piled up in one corner so kids could explore the creeks that ran to the Kansas River, which flowed alongside the town, and piles of b.u.t.terfly nets, and rows of microscopes, and a freshwater aquarium. A paper wasps' nest hung from the ceiling, and there were animal skulls and duck decoys. Terry Callender was a hunter, and it showed-not just in the veritable museum of taxidermy that also crowded the walls of his cla.s.sroom, but in the patient, observant, expectant att.i.tude he brought to the study of wild things.

"Divide yourselves into groups of threes and fours," he told the students when they had returned to their seats. "I'll be right back." And he was, carrying a box of envelopes he had just taken out of the refrigerator.

"OK. You are going to put a tag on each b.u.t.terfly and write down its number in the log. Then you are going to write down whether it is male or female. How do you tell the difference?"

"Something about the veins," one boy offered.

"Well, yes, there is something to that," the teacher said, "since the veins tend to be thicker on the females than on the males. But there's something else. Look at my shirt." The kids stared at his shirt, which meant staring at his substantial middle, which made a couple of them giggle.

"That one," a girl with long blond hair and braces said, pointing to one of the b.u.t.terflies. "It's a male."

Terry Callender beamed. "Right," he said. "See the dot? It's the pheromone sac. There's some controversy about whether it's functional or not, but only the males have them. Right. OK. When you're doing the log, I need you to write down wind speed-it's calm today; temperature-it's in the mid eighties; and the wing condition on a scale of one to four, where one is fresh and four is almost transparent because the scales have fallen off. When you're done, call for a runner-I need volunteers-and give your monarch to them and they'll go outside and release the b.u.t.terfly."

The students broke into groups, girls with girls, boys with boys, and before long the room was percussive. It's a one. Male. I think it's a two. Male. Female. Two. No, one. Runner, we need a runner. Female. Female. Two. Runner. The bell rang. A few kids with buses to catch took off. A bunch of others stayed. It was last period. The halls were filled with students eager to leave the building. Callender's students remained in their seats, s.e.xing the b.u.t.terflies. "They just can't seem to get enough of this," he said.

That Terry Callender's students even had any monarchs to tag was evidence, he said, of their interest in the project. In past years the b.u.t.terflies had been plentiful in Wamego-he recalled sending his own six-year-old into the front yard with a net, and the boy's returning a few minutes later with over a hundred monarchs-but this year they were scarce, coming in sporadically, not hanging around.

"This is the first time in four years that they haven't been here on the tenth of September in big, big numbers," he said. "Four years isn't a long time, but still, I think we were seeing a trend." We made plans to meet up again later, after the sun went down, in the city park.

WHERE I CAME FROM, jacklighting was the lazy way to bag a deer. Guys would troll the back roads in their pickups, shining bright lights into the edge of the forest, hoping to catch the reflection of a buck's eyes. The light would pin him there, and the guys wouldn't even have to get out of their truck. They'd just rest the rifle on the window ledge and shoot.

Jacklighting monarchs, Sandra Perez a.s.sured me, was nothing like that. For one thing it wasn't illegal. For another, it wasn't the light that paralyzed them; it was the temperature. They were already unable to move before the light was shined on them. This, it seemed to me, was a debater's point.

"We're going to shine the light under the branches and look for roosts," she said, ignoring my objections. "Sometimes they're hard to see. You have to be careful not to miss them because they blend in so well."

"It doesn't look good," Terry Callender said when we met up with him in the park. It was nine o'clock, and the reason he thought it did not look good was that his students had been out on the streets of Wamego for an hour and a half; he was pretty sure the town was already picked over. But then we walked a little farther into the park and Sandra shined a light on the underside of a silver maple and there, as if she were projecting it, was a small cl.u.s.ter of monarchs, crowding the branch like rush-hour straphangers on the Broadway Local.

"We'll snag them later," Terry said, hustling us out of the park and down a pleasant residential street of small houses with big porches. "We need to get to Mrs. Bradford's yard before the kids do. There are always monarchs there. Why that yard? Why those trees? There is no apparent reason. We tried to determine if they prefer one kind of tree to another, but they don't seem to."

We walked briskly, the sound of our footfalls seeming to precede us. There was no traffic; the streets were quiet, the houses welcoming. Muslin curtains, yellow light, roofs overhung by old, old trees.

Mrs. Bradford's trees looked like all the others. We inspected the one out front, then walked around to the back of the house. Terry Callender waved to Mrs. Bradford, who was on the phone inside. She hung up and came out just as Sandra was demonstrating her net-swiping technique. It was very smooth. Thirty monarchs tumbled into her clutches.

"Nice," Terry Callender said.

Some of his students appeared just then, walking out of the shadows as if they'd been summoned by an inaudible buzzer.

"What did you get?" they wanted to know-meaning "how many?"

"They're keeping score," Sandra whispered.