We were standing with Ron Bourque and shaking our fists at the Concorde when Bob Cook drove up in a Park Service van to say good-morning. Cook was not an amateur lark-lover looking for rarities; he was a full-time employee of Gateway's ominously-named Office of Resource Management and Compliance. This, however, turned out to be mere bureaucratese. What Bob Cook really did for a living was crash through the Barren Island underbrush and shove temperature probes up the tradesmen's entrances of noncompliant reptiles.

Introductions were made. Immediately, Cook invited my sister and me to come along on an expedition to the wildest part of the park -- the North Forty. This was the kind of unhesitant hospitality that was as much a fixture of Brooklyn life as egg creams and crack cocaine. We accepted, and in a couple of moments we had left Ron Bourque to his sparrows and we were off, just the five of us: the dog, the park ranger, the reporter, the Little Debbie, and the Little Debbie's suitcase full of trail mix, nature books, spring water, and organic apples.

The ranger was blue-eyed, with long, light-brown hair and wire-rimmed glasses that made him look like the young John Denver. Gus, the dog, was black-furred, sixteen months old, and extremely affectionate. We were a merry group, but there was serious business ahead of us. The mission to the North Forty would require Gus's skills as a retriever, and as a retriever, Gus was an absolute dork.

"He's a slow learner," Bob Cook said as we bounced along the runway. "He's having trouble adjusting. He was expelled from field-trial school. His father was a national champion, and gus couldn't cope with the burden of being his father's son. It's not likely he'll go back for his class reunions. He wouldn't have anything to brag about."

"Where did you get him?" the reporter asked.

"I ordered him from Maine,: the ranger replied. "I needed a turtle hound, so I mailed them a live turtle. Instead of throwing a pheasant for him to retrieve, they'd throw Gus a turtle."

"Throw?" I squawked.

"Figuratively," Bob Cook said.

The North Forty trail started from runway 6 and wound through grassland and young forest to a freshwater pond that had been created to attract and retain birds, amphibians, and reptiles such as the turtles Gus had been trained to sniff and fetch. Except for the model airplanes that were torturing the silence like aerial dentist's drills, it was quiet here, and remote from Hangar Row and Air Station Brooklyn.

"Take your time and enjoy it," said a Park Service brochure.

At trailheads in the National Parks, it was common for a clipboard to be posted to encourage birders to list any unusual species they had seen as a guide to those who followed. This practice had been followed here, but when I checked the roster it included: Dodo bird, Big Bird, Kangaroo, Lions and tigers and bears -- Oh, My!, Ducks, ducks, ducks, and schmucks."

Thus informed, we set out, armed for dodo, searching for any of the three hundred Eastern box turtles that Bob Cook had brought here from suburban Long Island in an attempt to reintroduce the species. To locate the animals, which spent most of their time hidden under piles of leaves, Bob Cook had glued radio transmitters to the shells of some of the turtles. He could home in on them in the event that his hound was unable to find them by smell.

Bob Cook was carrying some electronic gear and a flimsy antenna, held together with tape, that would pick up the signals. We were whacking through the Phragmites, merrily destroying habitat, while the ranger attenuated his receiver and mentioned, in passing, that it would be a good idea when we got home to check each other carefully for the ticks that might or might not carry Lyme disease. Great, I thought. I could look forward to seeing my sister in her underwear.

The life expectancy of the Eastern box turtle was the same as ours: eighty to a hundred years, God wiling. Bob COok had rescued his specimens from the projected sites of shopping malls and subdivisions, but he didn't know it they would like Brooklyn any better than the other immigrants I had met along Flatbush Avenue. Terrapene carolina was a homing turtle, compelled to return to its birthplace. But, like so many of the immigrants, the turtles of the North Forty could never go home.

"On Long Island," Cook said, "they would come out of hibernation and find themselves in the middle of a brand-new four-lane highway."

In the laboratory of our childhoods, I was the boy with the stickball bat, and Bob Cook was the one who kept a jar full of tadpoles. His father worked at a perfume factory in Queens, but there were relatives in Pennsylvania who fished and hunted and taught a city kid to value nature's treasures before killing them. Then the Earth Day movement of the late sixties stabbed him like a pin and awakened a concerned biologist.

"We're fighting two myths," he said as we paused in a clearing. "One is that people think there is no wildlife in New York City. The other is that people think there is nobody in New York City who knows anything about wildlife. The fact is, with the university community here, we have some of the world's greatest naturlaists. Of course, they're usually on expeditions in New Guinea."

Gus the hound came back from one of his random sorties with no new information. It looked as if we were going to have to rely on the radio. And, right on cue, it began to emit a soft, steady chip. Cook pointed the antenna this way and that, and we moved toward the source of the sound.

The dog was right beside us, but we saw the turtle before he did. It was a beautiful creature, as big as a man's hand, its upper shell -- technically, its plastron [Clara's note: this is exactly what he says] -- adorned with irregular shapes of gold and brown like a medieval map of the world. It was minding its own business in a dappled copse of sumac when the dog stepped right over it, completely oblivious.

"Gus, you can only get by for so long on good looks alone," his master said, dismayed.

The find was Eastern box turtle number 271, and it had Bob COok's telephone number on a sticker on its shell. The ranger had circulted flyers: "WANTED DEAD OR ALIVE. ANY AND ALL TURTLES FOUND ON OR NEAR FLOYD BENNETT FIELD."

But the Eastern box turtle was so secretive, and the underbrush so difficult of travel, it was unlikely that any would be spotted unless they crawled up onto the Belt Parkway to hitch a ride back home. Sixteen-month-old dogs, obviously, were no help. It was going to take a lot of electronic bushwhacking over a lot of years to find out whether the transplants had taken up residence in the North Forty.

Bob Cook knelt down next to the turtle and removed some instruments from his knapsack, which was a tenth the size of Little Debbie's. He changed the battery in the transmitter glued to its shell, noted the direction it was facing, the amount of shade and sunlight, and the temperature of the ground. He held it up for us to examine -- five claws on the front feet, four on the back. He gave Gus a good, long sniff.

There were fifteen dark rings around the perimeter of the plastron, one for each year of the turtle's life. The shell was hinged, and could be closed as tight as the door of a Mercedes roadster. There was a concavity in the undershell that identified number 271 as a male.

In mating, Eastern box turtles stacked themselves like inverted soup bowls, with the male always on top. In areas of low species density, Cook said, the females could store viable sperm for as long as four years, extracting just enough to fertilize each clutch of her eggs, conserving the rest in case she did not come across another male in the underpopulated undergrowth.

THen, while Debbie and I were nodding in awe of this man's knowledge and his deep respect for the animal kingdom, he took out a thermometer and shoved it up the reptile's rectum, and the poor thing opened its copper-toned eyes and popped out its legs and began to thrash the air like an Olympic swimmer on steroids.

Concluding an examination number 271 would never forget, Bob Cook packed up his stuff and turned on his receiver again, and we marched off to look for more turtles. We climbed out of the thicket and up a steep rise that turned out to be an abandoned ammunition bunker, a heavy concrete loaf from Navy days, now coated in bushes and weeds. It was rough country. Branches snapped in our faces and there were throns and bristles and sudden, treacherous pits.

"I'm surprised how little vandalism there seems to be in the park," I said as we struggled along. "I expected it would be full of homeless people, and that these bunkers would have been turned into crackhouses."

"Those people are afraid of nature," Bob Cook reasoned. "As soon as they step off the cement, they're traumatized."

We stood on top of the bunker and looked around at the cherry trees and the waving reeds. In the sixties, there had been a proposal to relocate 180,000 people from Bedford-Stuyvesant to a billion-dollar housing project on the tarmac of Floyd Bennett Field. All this would have been schools, hospitals, shops, offices.

It had not happened. One corner of the borough had been set aside, a small victory for nature in a mad, unnatural place. Safe and unsuspected, the North Forty enfolded us. I dreamed we were four days up the Limpopo, lost in the trackless veldt.

"Wilderness," I sighed. "This must be what attracted you to your work."

"No," said Bob Cook. "It was the ten-thousand-dollar reward for finding Jimmy Hoffa."