Kansas City, Mo. ? Not a beep. Mindy Walker stretched her long radio signal receiver out across the rocky den, waving it here and there.

Not a beep.

Nor a buzz, the sound of an aggravated timber rattlesnake.

Walker could only surmise that the last of the snakes’ batteries were dead, not surprising after 48 months. She hoped, at least, that the snakes weren’t.

Four years ago, the serpents were surgically implanted with radio transmitters, letting researchers track them as late as last summer. Now only silence greets the Rockhurst University assistant professor of biology amid the rocks.

So ends the Lenexa rattlesnake relocation project.

It began in the spring of 2007 after residents began seeing an increasing number of rattlesnakes in their neighborhoods.

One den wove through a massive pile of concrete and asphalt road rubble near Kansas 7 and 95th Street.

“I just saw a bunch of rattlesnakes lying around,” recalled city construction inspector Mike Shipman, who was checking on the site, which was slated for a never-built Target. He called Animal Control.

“I told them, ‘I think I found out where your snakes are coming from.’ “

For some, the first thought is to kill them. For others, it might be to give them an escort out of town.

Without question, rattlesnakes have a bad reputation among humans. For many, just the sight of one of these heat-sensing vipers with its large, angular head and black or brown chevron shapes conjures up a paralyzing fear or a violent reaction.

They even spooked Indiana Jones.

But Walker and others are not so ophidiophobic.

The first clue is when Walker calls timber rattlers “the puppy dogs of the rattlesnake world.”

The Kansas Department of Wildlife and Parks has warm feelings too, listing them among the “species in need of conservation” — animals that cannot be hunted or killed unless they are threatening to attack.

But the little rattlers, living and let living for as long as 20 to 25 years, are mild-mannered.

“Timbers will rarely rattle, let alone strike. It takes a lot of energy to strike,” Walker said, so the strike is saved for hunting and feeding. “Their first line of defense is to blend in.”

Walker thinks the relocation project was unprecedented — moving an entire nest of dozens to save them from ultimately fatal contact with humans.

Herpetologists and wildlife specialists from five surrounding states converged to help Walker and her research partner, retired KU professor George Pisani, now an adjunct with the Kansas Biological Survey.

“Our initial intent was to save as many as we could catch and move them,” Walker said.

However, these were not a few slithering singles, but a serpent community, established over a decade.

“Snakes have family groups, are familiar with one another, and they recognize their den mates,” said Walker.

“We saw an opportunity to test a new model of conservation — keep as many snakes from a single population together and move them to a suitable area. Our hope was that they could re-establish their same population somewhere else.”

The first spring after their discovery, a host of volunteers clutching grabbers snatched the emerging snakes and stuffed them into buckets.

“I think I caught 20 by myself,” Shipman said.

Many were kept at the Lenexa Police Department while Walker and Pisani implanted the transmitters.

Eventually, Pisani found a new den, the location a well-kept secret.

“We herded them one by one in the new den,” he said. “I mean we literally shooed them into the hole.”

The biggest worry was cold weather. If the habitat around the new den was too different, the serpents could die underground in hibernation.

“It was risky,” Walker said. “We didn’t know if they would survive the winter. When they did, when we heard the first signal, we were jumping up and down, elated.”

Not all survived. One, in shallow hibernation, froze. A raptor got another — the transmitter was found under a shade tree.

Pisani said Lenexa hasn’t had any rattlesnake problems since the relocation.

Today, Walker is known in the animal conservation kingdom for the successful relocation. She and her college student assistants have traveled the country telling the story. It has showed up in scientific journals such as the International Reptile Conservation Foundation.

Walker gets calls from across the country “wanting to know how we did it.” Usually, she said, when a rattlesnake is found in a residential area, it’s just moved about a mile away.

But before you plop one in your Prius for a spin, listen to the snake lady.

“It doesn’t work,” Walker said. “They will just follow their own scent right back home.”