Have you ever stuffed an owl into a tomato sauce can?

Norman Smith has. Lots of them, actually.

Today he’s working with two snowy owls — beautiful birds with downy white feathers, piercing yellow eyes, and talons you don’t want to go anywhere near. Smith holds them by the feet and pops them upside down into the device he’s rigged: two food cans, fastened together, with holes drilled in the bottom so the bird can breathe. Then the can goes onto a scale so the owl can be weighed. (Got a different size bird? Use a different size can.)

It’s one of the many tricks Smith has picked up on the job at the Blue Hills Trailside Museum, where for decades he’s rescued birds of all kinds who find themselves in tricky situations. In winter, that often means scooping up snowy owls from Logan Airport, where they like to congregate on the tarmac.

Why Logan?

“Nobody knows,” Smith said. “We’ve caught about 800 snowy owls out there, and I’ve asked every single one of them and they’ve never responded.” But he and other ornithologists have a theory: the desolate stretches of paved airstrips look a lot like the owls’ habitats up in the Arctic.

That’s a problem, because birds and airports don’t get along very well. Airports sometimes shoot and kill birds to prevent them from interfering with aircraft, and snowy owls are no exception. One was shot and killed at a Wisconsin airport last November, for example.

Perhaps the most infamous case happened in 2013, when workers at JFK Airport in New York City shot and killed three snowy owls. A federal judge later ruled that it was legal for them to do so, but public outcry was intense.

So intense, in fact, that JFK discontinued the practice. Now, they do things the Norman Smith way.

Norman Smith holds a snowy owl at the Blue Hills Trailside Museum in Milton, Mass. Amanda McGowan/WGBH News

The Norman Smith way involves going out on the airfields to look for birds, and then setting nets for them with some of their favorite snacks, like mice and rats. Nowadays — airport security being what it is — this process involves a lot of red tape. Smith has been cleared by the FBI, has a special driver's license he has to renew every year, and has to take out $10 million in liability coverage just in case. (One biologist at Mass Audubon jokes that Smith is “the only ornithologist in America with a security clearance.”)

Before September 11, 2001, this process was a little more freewheeling. Smith would go out on the weekend with his daughter, Danielle, walking around the airfields catching owls. Sometimes they came into close contact with more than just the birds.

“We were out there when President Clinton landed one day,” he said. “Air Force One came down and landed on the runway right beside us [as] we’re there catching a snowy owl.”

This may sound like an unusual weekend activity, but for the Smiths, birding was — and is — a family affair. Once, one of Danielle’s teachers called a parent conference because she thought Danielle had been making up elaborate stories about sitting out on Chickatawbut Hill putting bands on the legs of hawks (She wasn’t making up the stories.) Danielle says that growing up, it wasn’t unusual to have baby birds hanging around at home while her dad nursed them back to health.

“There was a constant rotation of baby hawks and owls through the house,” she said. “You never knew what he was going to come home with.”

Danielle even spearheaded research of her own — on the small and elusive saw-whet owl — when she was in high school. Now her kids are involved with birding as well.

Smith hopes that seeing nature up close at a young age will make kids more willing to protect it in the future. That’s why he puts so much energy into the educational aspect of the museum and the snowy owl tracking project. He has also been known to bring a snowy owl into his granddaughter’s kindergarten class.

“I’m just hoping these birds will survive for the remainder of time, and that my kids and my grandkids get a chance to see these birds in the future,” he says.

Norman Smith prepares to release a snowy owl at Salisbury Beach State Reservation in Salisbury, Mass. Amanda McGowan/WGBH News

Back at the museum, Smith has the owls in containers that resemble large black nurses' bags. He and Animal Care Assistant Sarah Lawson take them out one at a time for a medical inspection. They weigh them, measure their wingspans, check them for parasites, and take blood samples to see if the birds have been affected by toxins, heavy metals, or pesticides.

One of the things they’re on the lookout for is rodenticide. Lawson explains that many of the owls come in sick after eating rats poisoned with pesticides by local restaurants. These chemicals could end up being harmful to humans, too.

“In studying owls and hawks, you’re studying birds that are at the top of the food chain,” Danielle said. “Really, they’re similar to us. If something starts to go wrong with their population or if there’s a pesticide that’s coming up through them, eventually it’s going to reach us.”

Pesticides aren't the only threat to the snowy owl population. As the Arctic warms from climate change, their habitat is shifting. As the tundra warms and shrubs and trees begin to grow there, the animals the owls depend on to survive, like lemmings, may begin to disappear.

“This is certainly one of the birds that will probably be affected by any changes that happen up there,” Smith said.

Smith and Lawson fit the owls for identification bands with serial numbers on them, and some get satellite transmitters, too. From these, scientists have learned about the birds’ migratory patterns. During some years known as "irruption years," large numbers of snowy owls flood down from the north, sometimes traveling as far south as Bermuda and Florida. This data is recorded at Project Snowstorm, where people can track the owls and upload photos of ones they’ve spotted in their backyards.

“This year I had a woman send me a picture several weeks ago from Texas, from her cattle ranch. ‘He’s having a really good year eating gophers down here.’” Smith said.

Up close and personal with a snowy owl at the Blue Hills Trailside Museum in Milton, Mass. Amanda McGowan/WGBH News

Once the owls have been fully inspected, Smith takes them out to be released again. Today he’s chosen Salisbury Beach, about an hour north of where he caught them at Logan. He makes the drive with the owls in the back, and they hardly make a peep.

At the beach, Smith unloads one of the owls from the car as the wind whips around him.

“They’re such impressive birds, coming all the way down to the Arctic for a brief time in the winter," he said, holding the owl by its legs. "They’re getting ready to head back north again, head back home.”

Then, Smith releases the owl from his hand and watches as it flies away into the dunes.

Correction: An earlier version of this story incorrectly stated the location of the Blue Hills Trailside Museum, which is located in Milton, Mass., and also incorrectly described an owl as perched on Smith's wrist. Smith was holding the owl by its legs.