'Cutting' is looking; 'sign' is evidence. No technology is involved. Trackers look for tread designs printed in the soil and any incidental turbulence from a footfall or moving body. They notice the scuff insignia of milling hesitation at a fence and the sudden absence of spiderwebs between mesquite branches and the lugubrious residue of leaked moisture at the base of broken cactus spines. (The dry time is a stopwatch.) The best trackers know whether scatterings of limestone pebbles have come off human feet or deer hooves. They particularly value shininess-a foot compresses the earth in one direction, which makes it shine, and wind quickly unsettles this uniformity, so high-shining groups are irresistible.
Low-light cameras and night-vision goggles and thermal-imaging scopes and seismic sensors are useful along the river, but in the brushland north of it pretty much the only thing to do is follow illegal immigrants on foot. Nearly every southern Border Patrol station maintains a network of footprint traps called drags-twelve-foot-wide swaths of dirt that are combed every day with bolted- together tractor tires ball-hitched to the back of an SUV. Agents monitor drags endlessly and follow foreign prints into the brush.
One morning just after dawn, I was out with an agent named Mike McCarson. He was driving a customized Ford F-250 down a ranch road, cutting a drag that ran alongside it. The Rio Grande was close; the sky was unusually congested. The drag and the ranch road extended out of sight through mesquite and prickly-pear cactus and purple sage and huisache and whitehorn, all semiaridly dwarfish: the horizon was visible everywhere. Driving about eight mph, McCarson leaned out the window a bit, his hinged sideview mirror folded flush with the door.
McCarson is forty-three; he has been tracking illegal immigrants for eighteen years. He works out of the Border Patrol's Brackett-ville station, which is about twenty miles northeast of the Rio Grande and thirty miles east of the town of Del Rio. Brackettville's hundred and twenty agents are responsible for a twenty-five-hundred-square-mile rectangle of mesquite flat and limestone breaks. No more than forty agents are ever in the field at once- one per ninety square miles.
Federal guidelines recommend that undocumented aliens be apprehended at least five times before they're charged with illegal entry and held for trial, but Brackettville's agents rarely detain people unless they've been caught more than fifteen times. On any given trip, an illegal immigrant's odds of eluding Brackettville's defenses are extremely good. Immigrants can angle in from anywhere along a fifty-mile stretch of the Rio Grande, and overpowering numbers of people often cross the river simultaneously. Brackettville doesn't have the personnel to track more than five groups at once.
'It's just the luck of the draw which ones we chase,' McCarson told me as we drove. 'We generally don't even work groups as small as three, four people, or groups that happen to have crossed real early the night before.'
I spent many days with McCarson, cutting drags and trails and meandering through mesquite in the F-250. He is a big, sauntering, freewheelingly mouthy guy who says 'tars' for 'towers' and 'boo-coo' for 'beaucoup,' a word he uses a lot, sometimes as a noun ('There's boo-coos of trails through there'). McCarson instinctively registers the happenstance, ambient comedy of ordinary life, sometimes with a falsetto, arc-of-joy cackle. He likes to stop for lunch on hillsides and in old Seminole cemeteries, and he can be precipitately melodramatic. ('Now, the seasoned journeyman agent will see the totality of circumstances in his area and know precisely what's normal activity and what's not.') McCarson is married but doesn't have kids, which may partly explain his widely entrepreneurial imagination: he owns a scuba business on Lake Amistad; he's a partner in a San Angelo real-estate venture; he's a successful self-taught stock picker.
On the drag, we were seeing a lot of overlapping cloven-hoof sign, like combinations of the alphabet's last four letters. Agents have found sign of people crawling across drags on their hands and knees (long, chutelike impressions), and sign of people tiptoeing across drags (shoe-tip abbreviations), and sign of people walking across drags backward in socks (blunted images, kicked soil revealing the true direction of travel). Someone once walked across a drag on his hands (profound, torqued handprints); the man was followed from the drag to a railroad siding, where the prints transformed themselves into elongate gouges in the embankment stones: running hard, he'd jumped a freight. Sometimes, illegal immigrants will survey drags until they find a particularly rocky stretch and cross there, stepping only on stable rocks, as if they were fording a stream. If yielding terrain frames the rocks, they leave almost no sign.
Ideally, a tracker will find fresh prints on a drag, follow them until he can establish a line of travel, and radio in the group's drag coordinates, its heading, and its tread profile. Then another agent will cut the group on a drag some miles north or northeast-all the sheltering towns and safe houses and freight tracks and pickup points lie that way-and either catch it or radio in a revised line, allowing a third agent to leap up to the group. In practice, it's often impossible to categorically identify a group, establish a line, or get a forward cut.
Because the surest way to identify a group is by its distinct assembly of tread patterns, trackers use a lexicon of soles: super chevron, racetrack, wishbone eight ball, propeller, Tetris, basket weave, Kmart special, rifle sights, Flintstones, hourglass, running w, matchstick. When I was out with McCarson, the radio regularly issued sole descriptions: a 'diamond-within-a-diamond heel with an instep logo,' an 'island running w with a slash in the middle and a fine line,' a 'beetle pincer in the toe.' The increasing complexity of sneaker-sole designs frequently creates neologisms. Regions, and sometimes stations, have their own dialects: a sole dominated by lugs in the shape of a z is a 'zebar' in Brackettville and a 'zorro' in Del Rio.
We cut a blank stretch for a while. 'It's gonna be a little quiet,' McCarson said. 'We haven't had much moon.' The moon is a prime instrument of navigation, because it illuminates without stark exposure. (Illegal immigrants also use the sun, stars, and diverse landmarks.) A few minutes later, McCarson stopped the truck. 'Well, we got some crossers,' he said.
The prints were shallow and had been scrambled by super-imposition; it took McCarson about thirty seconds to disentangle the tread designs and stride lengths and foot sizes. I couldn't find a discrete print. 'Group of five,' he said: running w, matchstick, heavy-lug boot, fine wire mesh, star-in-the-heel waffle. 'They were here last night. They're fresh, but they're not smokin'-hot fresh. When the ground is retaining moisture like this, and you don't have much wind, the sign can hold its shape for a long time. But I see a little better color in our prints than in theirs.' Foot pressure, concentrating moisture in the soil, darkens prints; the clock of evaporation steadily lightens them. I couldn't see any color difference. 'They could be anytime last night,' McCarson said. 'And we've had the correct amount of moisture over the correct amount of time to make the ground about like concrete, so they're not leavin' much sign.'
If drag prints aren't decisive, trackers examine a group's sign along the first stretch of trail, wary of the corrosive or stabilizing effects of weather and terrain-hilltop wind withers prints; damp arroyos embalm them-and noticing things like insect crossings and preservative soil composition and raindrop cratering. Every left-behind object is a potential timekeeper. There are rare, unambiguous tokens: jettisoned cans of beans that ants haven't yet noticed, sunlit Kleenex still clammy with mucus, fresh bread crusts on a hot, clear day. But most often agents encounter noncommittal objects-desiccated bread crusts in full sun which could be two or ten hours old.
Swinging the shepherd's cane he uses as a tracking aid, Mc-Carson started cutting. Just beyond the drag was a strip of mesquite scrub, and then freight tracks on a high gravel embankment. In the scrub, the prints disappeared abruptly, as if the group had been choppered out. But McCarson read a carnival of sign through the scrub and followed a sequential displacement of gravel up the embankment. He pointed to a railroad tie and kept going. Possessed by the live trail, he couldn't pause to explain.
I sat down and studied the tie. It looked like every other tie. I began shifting position relative to the obfuscated sun. Eventually, three stacked ws of discoloration, collectively the size of a half- dollar, shimmied into view.
On the other side of the tracks, McCarson was standing in front of a fence, methodically locating the crossing point with his cane. Beyond the fence, the mesquite gave way to scrofulous pastureland. The wind picked up and a stop-start drizzle began. Any moderately heavy rain melts sign, toughens vegetation, and hardens the arid earth. McCarson walked along the edge of the scattershot grasses for a while, hesitant, and then accelerated.
He was mainly scrutinizing stalks of buffalo grass and curly mesquite grass and king ranch bluestem. The group had pressed the grasses forward. Now at a vestigial angle, the stalks reflected the light more directly, like opened compact mirrors, whitening it. Mc-Carson described this effect later; for the moment, my experience remained completely secondhand-even after he had amplified the sign by walking right over it, my glances fell nowhere.
I could see that moisture had strengthened and limbered up the grasses: instead of breaking and lying inert after receiving their foot-blows, which makes for the brightest reflection, they had been rebounding in slow motion for many hours, and had nearly regained their posture, although adhering rain droplets now pulled them down like sinkers and a jittery wind ceaselessly repositioned them. Under the dingy, dropped-down clouds, the reflective power of the grass was negligible, and the rainy light shrank the color differences.
The mesquite thickened; the grasses faded out; the static of drizzle hardened the ground and corroded the sign. 'This is some tough cuttin',' McCarson said, neutrally. The terrain was too stingy for prints, but the walkers had scored the earth with the soles of their shoes, and McCarson was following the scuff marks, which were often the size of fingernail clippings and about as much lighter than the surrounding earth as a No. 2 pencil is lighter than a No. 1.
In cow shit or ant-processed dirt or hoof-crushed earth, Mc-Carson found fractional footprints. Largely dismantled by drizzle and generally separated by a quarter mile, they were about the size of suit buttons. For retracing purposes, he marked them by scraping a line in the adjacent dirt with his cane. He kept moving and held the silence of his concentration, but there was satisfaction in the absoluteness of the stroke and the granular conclusive sound itself: shhhick!
The ground was still hardening; the rain-erosion got worse. McCarson slowed, occasionally bending down a little and poking something diagnostically with his cane, but he never crouched and almost never came to a full stop.
'Well, we're just suckin' on the hind teat on this one,' he said. A minute later he said, 'Oh, by God, that's them!' and accelerated down an alley of spectral sign. Five minutes later, he slowed again. 'The odds of following these five are pretty slim in these ground conditions,' he said. 'We're losin' so much time just tryin' to stay on the sign, we won't really catch 'em unless we take a risk.'
So we held their line and walked fast down numberless, seemingly uninstructive trails. McCarson's trail choices appeared to be random, but he was sensing the path of least resistance, relating it to the group's hypothetical line of travel and behavioral tendencies, and occasionally seeing candidate sign. A few times, where the ground turned permissive, we swept perpendicularly back and forth, hoping for trapped sign. After fifteen minutes, McCarson said he was beginning to doubt the trueness of the line.
We walked windingly for maybe a mile. Suddenly McCarson stopped, reached down, and picked something up. All the quick walking had reminded me that we were operating in undifferenti-ated wilderness the size of two Rhode Islands. McCarson stood and opened his palm. In it was an aspirin-size mud clot distinguished by a sole-honed ridge with a strict curvature. He handed it to me and kept going. A ludicrously deteriorated trail of disturbance had nonetheless held its integrity, in McCarson's eyes, for about five miles. The clot seemed talismanic. But we never got a forward cut, the weather didn't improve, and the trail died.
'We never know who we're gonna catch,' McCarson told me on the way back to the station. 'The weather plays a tremendous role. You get into drought conditions and you can run groups until you lose daylight and never stall out. A hard rain and you lose all your sign. It's just shithouse luck if we catch 'em.
'Our real effectiveness is in actin' as a screenin' mechanism- we're a deterrent, which is not something you can really see out in the field, and some agents that might not love tracking get really hung up on that. They can't get over it, and they turn into sorry, disgruntled agents. What this job boils down to is desire-you started with a hundred sets of tracks on your drags, and you're trying to get ten. It's not a factory job-there's no boss, you're not stamping out x number of product. What determines that you should try to catch those ten when ninety are already gone? I know what you really wanna ask, which you haven't asked it yet, is how many get away. Well, they all get away. That's the answer. Eventually, they all get away.'
McCarson grew up working on his grandfather's ranch, outside Comstock, which is about fifty miles northwest of Brackett-ville. The ranch didn't keep him entirely busy; as soon as he was old enough, he began hiring himself out to bigger local ranches, where he worked through the daylight hours and then traded money at cards and dice in bunkhouses until he could spend it in town on his day off. He never felt a desire to leave southwest Texas. He studied government at Angelo State University, but by the time he graduated livestock-raising in the region had lost most of its commercial viability.
McCarson had always liked the gun-slinging look of Com-stock's Border Patrol agents, and noticed that they often worked without supervision. 'That's what really did it,' McCarson told me. 'Because I liked to hunt and fish, and it looked more like huntin' and fishin' than workin'-they'd give you a vehicle and you were on your own.'
When he began tracking, he saw immediately that his hunting skills were almost useless for following people. Border Patrol trainees learn to track informally and opportunistically, tailing journeymen on live trails and asking questions as circumstances permit. McCarson augmented the process by walking exhausted, still-legible trails whenever he could, as far as he could, which is generally encouraged but not frequently undertaken because agents have to do it on their own time.
'Everything you need to know about tracking I can explain in about two sentences,' he told me. 'You're evaluating the ground for the difference between the disturbance made by humans and the disturbance made by any other force. After that, it's all practice. It's all just looking.'
A planetary difference in vision separates great trackers from ordinary trackers. At Brackettville, McCarson and about a dozen other trackers occupy a paramount plane. 'There's just a certain level you get to, where you can't say who's better,' McCarson says. 'And I can't even tell you what that level is as far as particular sign-it's just, if there's something there, we'll see it.'
