The pioneers who founded Israel were human, and therefore were not free from the law of unanticipated consequences.

When they first got to Israel, the pioneers battled the swamps in the Galilee, which not only made agriculture difficult but often made life impossible. The mosquitoes that bred in the swamps carried malaria, which is deadly if it is not treated. So, in the early 1950s, soon after the State of Israel was recognized, the swamps in the Hula valley were drained. It was a major Zionist victory, a triumph of science and strength and will over brute nature.

But brute nature fought back.

The draining of the Hula caused a whole range of problems; the exposed peat that had been beneath the swamps proved toxic, and the wildlife that had flourished died. In the mid 1990s, part of the valley was reflooded.

In 1953, as the draining of the swamp began, a group of prescient Israelis, who foresaw some of the problems and intuited others, formed the Society for the Protection of Nature in Israel; the reflooding of some of the valley, 40 years after it was drained, is due to the group’s tenacity and commitment both to nature and to science.

“That was very early for the environmental movement,” Leon Sokol of Teaneck said; he and Russell Rothman, who lives in Oradell, are the co-chairs of the American Friends of SPNI. “They were way ahead of their time. And from that sprang the development of SPNI. Now it has more than 160,000 members.” Mr. Sokol recently returned from a trip to Israel with AFSPNI — the most recent of many such trips.

The group is firmly planted in Israeli life, Mr. Sokol said. “They are the leaders in terms of education advocacy. They have a seat on every local planning board, and they are a voice for protecting air and water quality, and for sustainability.”

On some of his trips to Israel, Mr. Sokol has seen one of the most visually striking (and perhaps globally important) results of the resurgent wetlands in Hula. The area is part of the Syrian-African Rift Valley that connects Africa, Europe, and Asia, and it is on the route that migrating birds take twice a year.

“Five hundred million birds fly over Israel,” Mr. Sokol said. “That’s 500,000,000, as in eight zeros. In the spring, they go north from Africa, and they land in Eilat for what would be refueling were they engines, not mammals; in the fall, they come from Europe and Asia to go south for the winter. Then, their major stop is in the Hula Valley.

“It takes about three weeks, and it is incredible to watch,” Mr. Sokol said. “One day, we were there when a flock of cranes from Sweden was heading south. A crane has a six-foot wing span, and they fly in a perfect triangle. The same flock will land on the same spot on the bank of the Hula every year, and do the same thing in the other direction. Their navigational skills are incredible.”

So are their organizational skills. “They fly in squadrons,” he said. “Each squadron has about 30 or 40 cranes. They rotate leaders, because the birds in the back work the least.” That’s because they don’t have to fight the air currents, as the birds in the front do, but instead can coast on their work. The rotation makes it all work out fairly.

Last year, Leon, center, and his late wife, Marilyn, their daughter Debbie, and two grandchildren, Zoe and Alex, went to Israel together. It was Marilyn’s last trip there.

“And when they come in, each squadron settles as if they were directed by an air traffic controller,” Mr. Sokol said.

“Israelis know all about it,” he added. “You ask any Israeli, and they will tell you.”

The SPNI includes “some of the world’s foremost birding experts,” Mr. Sokol said. Its birding team, Champions of the Flyway, enters — and wins — competitions around the world. Those competitions include the annual World Series of Birding in Cape May; the team won a competition in that series last weekend, as it has almost every year for decades.

Back in Israel, would-be birders can learn from the experts. The SPNI “maintains field schools for guided hikes,” Mr. Sokol said. Tourists can stay there; “the rooms are Spartan, but they’re nice,” and the instruction is serious.

The SPNI’s definition of nature goes beyond the flora and fauna; it is also vitally interested in human nature. One of its key projects is the creation of kehillot, communities of interest, in Israel. “We have taken vacant lots in low- or middle-income neighborhoods, empty lots like the ones you see in Brooklyn or the Bronx that have been turned into gardens. We take those lots, and we say, ‘Let’s clean up the lot, and we will show you how to plant a garden.’”

Those lots often are in ethnically mixed neighborhoods, some of them mainly Jewish, some not. Mr. Sokol talked about a lot in Haifa, in “a neighborhood that had a lot of Eastern European and North African Jews, and some Arabs.

“The SPNI took those lots and developed them. Not only did they bring a horticulturalist, they also brought a social worker. The groups had not been integrated, but the social worker taught them how to be a neighborhood.

“There are individual plots in the garden, and people also work together. So now, instead of people who happened to live near each other, you also have a community.

“So our work isn’t only environmental. It’s also social.”

SPNI even has been able to get ostensible enemies to work together to solve shared problems. “Rodent infestation was a big issue for farmers in Israel and in Jordan,” Mr. Sokol said. “We figured out that barn owls can get rid of the rodents without pesticides, and they taught farmers in the West Bank and Jordan how to do it. And now they get together to protect their crops.”

Working together is a value that SPNI practices as well as preaches, Mr. Sokol said. In Beersheba, SPNI worked with the Jewish National Fund to help clean up the river. The clean-up — a huge job — was done mainly by the JNF and other groups; the SPNI contributed by offering programs “in the schools and the community,” Mr. Sokol said. “There is an environmental club in the high school, and an Arab girl is president. They all have a common interest.

“We are one of the organizations that gets involved with trying to get more communication between Arabs and Jews in protecting their communities.”

In yet another example of the idea of the environment as including people, and of the importance of various groups working together as parts of one larger ecosystem, “in the town of Bat Yam, south of Tel Aviv, there is a halfway house for people who suffer from mental illness,” Mr. Sokol said. Enosh House, as it is called, is run by the Israeli Mental Health Association. Part of the rehab it offers is to teach people how to cook and work; the kitchens offer vocational training too. They also make scented soaps and candles, and SPNI plans to “set up a hydroponic garden to grow the herbs to scent the soaps and candles, and to grow the herbs they use in the kitchen.

“That’s the kind of thing that SPNI does. It’s not sexy — but it makes a difference.”

Mr. Sokol has been on AFSPNI’s board for 20 years and has been its co-chair for eight. It was a natural cause for him. “I’ve always been involved in environmentalism,” he said. His first law firm, Sokol Behot LLP, was an early practitioner of environmental law. “It deals with land use and the rivers, wetlands, and waterways along the coast, the shore, the pinelands — which is 25 percent of land in New Jersey.” Environmental law in New Jersey, as in the country as a whole, as in Israel, is about “striking a balance that allows land development but respects the environment,” he said. And, of course, striking a balance always sounds easier than it is.

Mr. Sokol now is a senior partner at Cullen and Dykman in Hackensack; the environment continues to be his passion, and AFSPNI gives him a way to put that passion into action.