In Aztec lore, butterflies bear the souls of the dead back to life.

Those nether spirits were a bit scarce last summer in Lee and Carolyn Halbur's milkweed gardens along Fish Lake in Maple Grove. It was an off year for the monarch butterflies that the family has raised in prodigious numbers in seasons past.

"We were on track to have our biggest year yet but we lost a lot of them," Carolyn said. "Some were slightly deformed. It could have been the smoke from forest fires out West or parasites or something else — who knows?"

For the past five years, the Halburs have tended to the rust-colored butterflies with bold black stripes on their regal wings. The couple have planted milkweed, the monarchs' primary food source, all along their .4-acre property.

They have collected butterfly eggs and larvae from the underside of leaves, bringing them into their home for safety. Spiders, ants and beetles find monarch eggs and larvae delectable. Birds fancy the caterpillars. Wasps chomp on the monarchs themselves.

When the eggs have hatched and it's time to let the monarchs spread their wings and fly, they release the butterflies along the lake, making a family mini-festival of it. The Halburs' monarch preservation efforts have earned them a Star Tribune Beautiful Garden honor in the paper's annual reader contest.

Passion of a convert

Their passion for butterflies sprung from their own growing environmental appreciation and education. About 20 years ago, they initiated a lakeshore restoration project to protect the shoreline of Fish Lake, where they have lived for 28 years.

The milkweeds are among the deep-rooted native plants that they use for shore preservation. Carolyn, a fashion stylist, carries more of the passion for the larger lake where the family often spends happy hours on their pontoon boat and where she water-skis. Lee swoons over the butterflies.

"It's almost a spiritual experience to see the metamorphosis that happens from this tiny speck of an egg to the pooping caterpillar to this beautiful monarch," Lee said. "It's a natural thing that's hard to get into words. How do you measure the beauty of a sunrise or sunset? What do you say in front of a great painting?"

If Lee, a retired electrical salesman, has the passion of a new convert, it's partly because he used to have a negative view of their primary sustenance, milkweed. He grew up on a farm in the southwestern Minnesota town of Iona. There, milkweed was "like the devil," he said. "We wanted to have more beans and corn. So, it was something that had to be uprooted and destroyed."

"Some people still feel that way, sadly," Carolyn said.

But all of that is changing. Monarchs are a charismatic species that migrate hither and yon without passports or visas. They count North and Central America as home and travel back and forth in a journey that's still a marvel. It takes at least four generations of monarchs to complete the round trip.

The cycle begins with a brood in the oyamel fir forests in central Mexico, where they carpet trees through the winter. In the spring that generation migrates to the southwestern U.S., where they mate and die in places like Texas, New Mexico and Louisiana. Their offspring travel north to Minnesota and Canada, reproducing along the way.

Methuselah generation

The last generation is born in mid- to late summer. It is this brood that draws the oohs and aahs from kids and adults alike. These super monarchs, which some call the Methuselah generation because they are so relatively long-lived, travel all the way from Canada and the northern rims of the U.S. to Mexico's Sierra Nevada, the country's highest peaks.

After that journey of up to 3,000 miles, they overwinter in Mexico then return to Texas and Louisiana the following spring, restarting the whole cycle.

Late last August, the Halburs gathered with their grandchildren to release the few super monarchs they had raised. Granddaughters Nora Reckinger, 8, and Audrey Reckinger, 5, were all smiles as the couple opened the cages and let the butterflies fly.

One did not want to go, landing in the girls' hair.

"Aah," Carolyn doted.

Also on hand that day was Kathleen Pomerleau. She and her husband, Rich, have been raising monarchs for years. They, in fact, are the ones who introduced the Halburs to the conservation effort and have coached them.

The private lives of monarchs

Kathleen is an expert on monarchs, happy to talk about their private lives.

"The eggs are like ivory pearls," she said. Those eggs are collected and later hatch into caterpillars. That's when the fun starts. Each caterpillar can eat a complete leaf a day, excreting frass at the other end. The poop is collected on paper towels at the bottom of the cage. They grow exponentially in five instars, or stages between molts, before climbing up and forming the letter "J."

"In 24 hours, they turn from caterpillar to chrysalis, a little green pod," Carolyn said. "In eight to 10 days, they break the pod and a butterfly emerges," stretching out its soft, wet wings.

It is that transformation that has transfixed humans for generations. Once people experience it close up, they are won over, Lee said.

"It's a natural thing that makes you convinced that there's life after death," he said. "Seeing that maggot of mush turn to a beautiful monarch, you can't help but know that we're more than just a body. We're a soul."

But it's not all spiritual wonderment for the Halburs, who do get down to Mexico, the monarchs' winter home, from time to time.

"I probably see enough monarchs in the regular season," Lee said, "so if I go into the wintertime, it's for the beaches and the beer."