GUILDERLAND — Serious students walk carefully, one behind the other, as each holds a long white rod, looking rather like The Flying Wallendas balancing on a tightrope. They are Farnsworth Middle School seventh-graders, learning by doing.

This week, at the Albany Pine Bush Preserve, they are using the same method used by ecologists to monitor the Karner blue butterfly, which is on the federal list for endangered species.

In a protocol called “transect sampling,” the students walk a set path or “transect” to count the number of Karner blue butterflies they see. To practice the technique, models of the butterflies are used.

“Scientists would walk it year after year,” explained Farnsworth science teacher Alan Fiero “to see how the population changes.

“The strange thing is,” he went on, “when you walk your path, you see a lot of butterflies close to you but, at more of a distance, you see less.”

Each pole is divided into four sections; the kids count how many butterflies they see in each section. Then, back in the classroom, they calculate, using their counts, how many butterflies would be in a larger area.

The students at the preserve wear white gaiters and anoraks to protect themselves from ticks. “Part of the treat is, they look like scientists, so they act like scientists,” said Fiero.

Grace Barber, a staffer at the Pine Bush Preserve Commission, showed the young scientists how to take readings on temperature, wind, and cloud cover. The students dutifully tracked these readings, writing on papers anchored to their clipboards.

“They affect the number of butterflies,” said Fiero of the readings.

Fiero has high praise for the Pine Bush Preserve Commission. He has worked with the not-for-profit organization for decades on projects that both taught his students and benefited the preserve. “The commission helps us write the lessons and works with us in the field,” he said.

Fiero’s seventh-graders along with remedial math students taught by Judith Carnavos and Ashley Girard worked on the project at the Pine Bush Preserve this past week. Fiero hopes to expand the project to other classes, using the lawn on the middle-school campus.

“They love getting outside,” Fiero said of his students. “One kid said he wanted to lay down in the sun.”

Kids making the trek to the Pine Bush Preserve last week were thrilled to see real Karner blue butterflies after studying them for so long. “After all the habitat restoration, the girdling, the artificial rearing, they were ecstatic to see real Karner blues,” said Fiero. Farnsworth students have worked on cultivating native plants — the Karner blue depends on wild lupine. The students have also girdled aspen trees, cutting rings around the girth of trees to prevent them from spreading.

When Fiero first started bringing his students to the Pine Bush 20 years ago, the butterflies numbered in the hundreds. “Now they’re in the thousands,” he said.

The current project is being funded with a $6,000 member item grant secured through Assemblywoman Patricia Fahy. In addition to using science and math skills, the Farnsworth students are also using language arts to prepare presentations on what they’ve found.

English teacher Molly Fanning is teaching them about Google slides software, Fiero said. “The kids have 10 to 20 seconds to describe each slide in a series,” he said.

“People may not like Common Core,” Fiero said of controversial learning standards that have been adopted by many states including New York, “but one of the big things is kids have to become communicators and evaluators; they have to be able to critique and share information.”

He went on, “It’s an important goal for us as teachers to have students be thinkers rather than memorizers.”

The implementation of the new standards was poor, Fiero said, explaining, “You have to build from the bottom up,” but, he concluded, “Most teachers like the Common Core.”

When Fiero interviewed to be a Guilderland teacher in the early 1980s, he recalls saying, “Children should be scientists…They should think and act like scientists.”

Fiero has always taught that way, with a hands-on approach, and believes that approach is now more important than ever. “Students have to look carefully with a skeptical eye and use evidence from the world as a basis for their conclusions,” said Fiero.

He went on, “I tell the kids the definition of science is to look for relationships in the natural world, look to see how things connect. Be a skeptic. Do things logically.”

Asked if students are different now than when he started teaching more than three decades ago, Fiero said, “At the middle school, they still love to learn. They still have that curiosity and are willing to take a chance.”

However, he went on, “Physically, kids nowadays don’t have the physical stamina of the past. It’s a shame.”

He concluded, “I love getting kids outside, out of their seats, doing physical things. We’re still constantly looking for ways to involve kids in lifelong learning.”