Biologist Vagn Flyger anesthetizes a squirrel by putting its head in a mayonnaise jar that contains anesthesia-soaked cotton. (John Hadidian)

Old-timers will recall that the 1970s were an altogether grittier time in America’s cities. In New York, Times Square was a trash-strewn neighborhood overrun by junkies, pimps and prostitutes.

Meanwhile, here in Washington, Lafayette Square was overrun by Sciurus carolinensis, the Eastern gray squirrel, a shakedown artist as aggressive as any three-card monte hustler. Researchers tallied what many believe was the highest density of squirrels ever recorded in scientific literature: roughly 20 squirrels per acre.

“There must be 100 squirrels in that small square now, and they’re just shredding the trees,” Bill Ruback, National Park Service ranger in charge of the White House grounds, told The Post in 1977.

[Where did D.C.’s black squirrels come from? Blame Canada.]

Heirloom trees — many planted by visiting dignitaries — were stunted and deformed by squirrels. The rodents were also digging up bulbs and chowing down on flowers.

A park service employee removes a nest box from a tree at Lafayette Square. (JK/John Hadidian)

“They ate over $2,200 worth of geraniums in two days,” Ruback said.

Why so many squirrels? There were a couple of reasons, said John Hadidian, who met me at Lafayette Square not long ago to reminisce. John just retired from the Humane Society of the United States, but in the 1980s, he worked for the National Park Service’s Center for Urban Ecology. As he and his co-authors put it in a scientific paper published in 1987: “Intensive provisioning by the public was implicated as one of the main factors responsible for this.”

[What’s the deal with white squirrels?]

Intensive provisioning: People were feeding the squirrels.

Over-feeding them, in the estimation of the Park Service, which found that 75 pounds of peanuts were being distributed in Lafayette Square each week. (One of the intensive provisioners was Concepcion Pioccotto, who lived in the park while protesting nuclear weapons.)

There were also dozens of nest boxes in the park’s trees. No one could remember who first put them there, but the Park Service grudgingly maintained them even though the artificial habitats boosted the squirrel population.

How to bring the numbers down? The obvious solution was euthanasia, but officials feared a public backlash.

John Hadidian, who in the 1980s worked for the National Park Service and was involved in relocating close to 100 squirrels from Lafayette Square. The squirrels were damaging trees and plantings in the historic park. (John Kelly /The Washington Post)

“We talked about contraception,” said John, a veteran of the operation. “We had a good deal of inquiry with people who were knowledgeable about it.”

Someone suggested a compound that was used on cattle, but it turned out to be carcinogenic.

“That was out,” John said. “Then in 1985, we had dropped in our laps one of the most abundant acorn crops that we’ve ever seen here.”

Suddenly, Washington was awash in nuts — real ones, not politicians. It seemed to be a message from on high. If some of the squirrels could be moved from Lafayette Square, it was likely they wouldn’t starve in their new location.

A team was assembled, and an action plan formulated. Zero Hour was 10:30 p.m. on Oct. 17, 1985, a time when the squirrels would be asleep — and so would most curious tourists and pesky reporters.

The biologists removed the saw blades from long pruning poles and replaced them with pantyhose stuffed with newspaper. These were used to plug the holes in the nest boxes — “so they didn’t all come pouring out,” John said.

A ladder was used to remove each nest box, which was brought to a kiosk in the center of the park. The main squirrel handler was Vagn Flyger, a famed squirrel whisperer from the University of Maryland. (Flyger was known for smearing Valium-laced peanut butter on the trees behind his Silver Spring home, then tattooing the squirrels’ anesthetized bodies so he could later distinguish them from one another.)

“He’d grab them, and he’d stick their heads in a mayonnaise jar in which there was cotton soaked in anesthesia,” John said.

Once asleep, the squirrels were inspected, then put in cages.

“There were millions of fleas, unbelievable,” John said. “They were jumping on everyone.”

Surely you wore gloves, I said. Not Flyger, said John.

“At one point during the night, a squirrel got him, put his incisors right through the fleshy part of his middle finger,” John said. “I remember him raising his hand, blood’s running down and the squirrel’s hanging on. He just detached it and went on. He was a real old-time biologist.”

Forty squirrels were captured that night, an additional 38 the following week and a further 17 in January 1987, for a total of 95, more than half of Lafayette Square’s population. They were taken in a convoy of vehicles to Park Service land across the Anacostia, mainly Fort Dupont Park, where they were released.

Today, biologists believe that relocation isn’t a good idea. Relocated squirrels are unfamiliar with their new habitat and are not welcomed by resident squirrels. But it seemed to work at Lafayette Square. The nest boxes were removed, and signs prohibiting feeding were put up. Today, there is equilibrium. But the issue of carrying capacity — how many wild animals “belong” in a certain area — is still controversial, whether it’s squirrels in Lafayette Square or elk in Yosemite.

As John and I sat on a bench opposite the White House, watching tourists take snapshots of squirrels, I asked whether he and his fellow commandos had given their nighttime raids a name. Operation Flying Fur? Operation Noble Incisor?

No, John said. “We should have, but we didn’t.”

Tomorrow: Finding deeper meaning in a water-skiing squirrel.

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/johnkelly.