A man who plans to fly stands differently than a simple sightseer. In his shoulders, there's a hint of a twitch. He tiptoes around the cliff top, plotting an approach. His eyes wander left and right, up and down, and his expression goes half-abstract, as if he's attempting long division in his head.

Jesse shows all the signs. And he fits the demographic profile: He's barely old enough to drink. He looks north toward La Jolla Shores, south toward the cove. If something goes wrong here, he will break bones or drown or get slapped with a $290 fine; this is illegal.

Yet for a century or so, the brave and stupid youth of La Jolla and beyond have been jumping from these rocks, which are collectively known as the Clam. Most of the takeoff spots — the Point, Bear Claw, the Pedestal, the Washing Machine — stand about 35 feet above the water, roughly the height of an Olympic diving platform. Or, if you truly have a death wish, there's Dead Man's at 107 feet. For further history and geography, check out http://www.theclam.com — don't even pretend you're surprised by that — and you find the fond reminiscences of a 76-year-old in Utah who did it in 1942, a 55-year-old who did it in the '60s with her Presbyterian youth group. Like Jesse now, they had the adrenaline thing happening. The responsible adult brain function, not so much.

Jesse started in seventh grade, when a bunch of the kids clambered onto these cliffs and a girl jumped. A girl. So he had to.

But that was nine years ago. Now there are more kayaks below, more signs, barriers and law-abiding tourists above. Down in the water (10 to 30 feet deep, depending on tide and season), alongside the scattered kelp and the occasional orange flash of a garibaldi, the kayakers congregate to check out the sea caves, the sea lions, the strange rocks.

If you're a jumper, this means one more set of obstacles to dodge. And the lifeguards are wiser and stricter now. There's one stationed a quarter-mile to the south with a clear sightline to these rocks. With all these "cliff jumping prohibited" signs around, you can hardly claim ignorance.

"We probably issue five to 10 citations a year," says San Diego Lifeguard Service spokesman Brant Bass. "We've got it pretty well under control, we think."

Jesse, the exception, is tall and shirtless. He wears a ponytail, baggy black trunks, soggy white socks. To ease the rock climbing on the way back up, maybe. He lives in landlocked La Mesa, tries to get over this way every few weeks. His launch spot today is the Point.

With him is Chris, another 22-year-old, head shaved clean. Chris will be making his first jump, once Jesse has shown the way. Jesse points. Chris stands back two steps. Then Jesse goes quiet.

Down at sea level, a kayaker notices.

"Hey," he says. "These guys are gonna jump!"

Jesse takes a step. Then another. Then two more and launches. And flies.

Witnesses everywhere. Some of the kayakers look young and hip, likely to keep quiet. Some are paddling their kids around on two-seaters. The snorkelers stare down mostly, not up. Then on the next rock outcropping, there's a semi-suspicious silent guy in a straw hat. (That's your Wild West columnist, lying low so as not to affect anyone's decision-making.)

Some of the tourists look parental. Given a chance, they'd probably remind Jesse of that $290 fine or tell him the story of the 19-year-old who died here nine years ago, or the 18-year-old twins who died after jumping with a group of friends in 1996. Later that year, the City Council boosted the fine.

Jesse doesn't know those stories. He sails through air, splashes down feet and butt first, comes up hooting like one more sea lion.

"Yeah!" he says. "Dude! Jump it! That's sick, dude!"

As he climbs back up, the columnist steps up, introduces himself, tells about the twins, agrees to leave last names out, hears about the thrill of it all.

The rush is "being in the air," Jesse says. "Right when you get off, in the middle of the fall, it's just so intense. You can feel the Earth pulling you."

Meanwhile, Chris the rookie stands on the launch rock, imagining strides, doing that long division. Long moments pass. Down below, a girl in a kayak says, in a mocking tone, "one … two … three … "

So there's no choice for Chris either. He launches, sun glinting off that hairless head, and grabs his nose. That costs him points for style, but splashdown is perfect. A whoop from the kayaks. A louder whoop from the jumper, bursting up from below.

"He did the nose-plug thing!" hoots Jesse, bent over with laughter. But Chris is pumped, and pretty soon he's back up top.

That's when a new voice rings out. Stern. Coming from below.

"You guys aren't doing any jumping, are you?"

It's a lifeguard. Just paddled over on her board. She is not amused, especially when they grin and deny all wrongdoing.

"You know," she says, "we can see you from the point over there. So if you jump again, we'll cite you."

They deny it again, and the lifeguard paddles off. But this is the first time Jesse's ever been warned like this, and he looks like a guy who'd miss the $290. He and Chris exchange looks.

Maybe this is it. Right here, right now, a century of reckless ritual comes to a finish, extinguished by new recreational habits, ascendant common sense and alert law enforcement. The Clam, dead at last.

Or not.

"Good lookin' lifeguard there," murmurs Jesse as she moves on. It's as if she never spoke. Jesse is 22 years old.

The Clam is dead. Long live the Clam.

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To e-mail Christopher Reynolds or to read his previous Wild West columns, go to latimes.com/chrisreynolds.