Experts say Portlanders shouldn't bother planting milkweed - the monarch butterflies won't come. But one woman found 30 eggs on her two plants this month, and she's urging others: "If you plant it, they will come."

Now some scientists see a hint of hope for the brightly colored butterflies that used to migrate through the region in the tens of thousands, but are rarely seen now because of the loss of their native food.

Monarch butterflies on the east coast travel to Mexico each winter, and those on the west side migrate to California. But a shortage of milkweed - their sole food source as caterpillars - has caused them to decline by 90 percent since the 1990s.

Patti Farris, 58, incorporated milkweeds in front of her house three years ago. She hoped monarchs would appear, but didn't exactly expect it.

On June 4, she noticed a butterfly circling her plants. Generally a monarch will lay one or two eggs per plant. This one laid 30 between two.

Tom Landis, a retired nursery specialist from the U.S. Forest Service, called this unusual.

"What I think it speaks to is that there aren't that many milkweed in the Portland area," he said.

Landis grew up in southern Kansas and remembers monarchs as a staple of his childhood. When he moved to the Northwest later in life and stopped seeing them, he decided to do some research.

Using his knowledge of native plants, the Medford resident said he began growing milkweed and raising monarch caterpillars. He now travels all over the region and gives workshops on caring for the plants and bugs.

Landis said he considered leading a workshop in Portland, but local experts told him it was a lost cause.

According to the Center for Biological Diversity, a national group for the protection of endangered species, it was the invention of roundup ready crops in 1996 that caused the major milkweed decline.

Lori Ann Burd, environmental health director for the center, said genetically engineered crops withstood an herbicide dose that would normally kill them off. This led to increased herbicide use, which is an effective milkweed killer.

What's left of the Northwest milkweed grows mostly in eastern Oregon and Washington.

Farris found Landis online and told him what she found.

"I was kind of flabbergasted," he said.

And this isn't an isolated spotting.

Dr. David James, an associate professor of entomology at Washington State University, said there are many sightings on the west side this year. Monarchs were even reported Wednesday in western British Columbia, where he said only a handful has ever been recorded.

Farris found James through the Facebook page Monarch Butterflies in the Pacific Northwest.

The professor has studied monarch biology and migration routes as part of a long-term research program at Washington State University since 2012.

Monarchs, he said, have been tagged for decades. Little stickers on their hind wings contain an email address and serial number so onlookers can alert researchers of their whereabouts. But tagging them in the Pacific Northwest is new.

He said many of the butterflies in the region migrate to California, but he wants to prove that some make it to Mexico, too.

"People think butterflies are very fragile," he said. "The monarch isn't very fragile. It's quite tough. You can hold it by its body. You just put it on the underside of the hind wing. The tags are very sticky."

James is sending tags to Farris.

The Portland resident said she initially tried leaving the eggs outside, but Landis warned her that less than 5 percent of eggs make it to adulthood. They often fall prey to disease and predators. Farris said every time she checked on the eggs, she would notice another visitor on the milkweed that could eat them. She couldn't bear the thought of leaving the eggs to a spider.

She started clipping off the leaves with eggs and brought them inside her house. If she could save just one caterpillar it made a difference in her eyes.

On June 8, all but two started hatching.

"The fact that any of them survive is a miracle to me," Farris said. "It's a cold, cruel world when you're a butterfly."

The following weeks were spent scrambling to provide milkweed. Fortunately for her, Farris' neighbor donated some, and she also found plenty at a nearby bioswale.

At first she kept two or three caterpillars in tupperware containers throughout her house, but it was hard to keep the milkweed fresh that way. Then she built a screened-in habitat for her dining room. In the morning she would fill the habitat with the plant. By the afternoon she had to fill it again.

The first caterpillar pupated June 21. By Wednesday, only a few had not yet pupated. More than 20 little green sacks hang from the top of the habitat. Blue tape with a date, time and assigned number mark each location. Farris wants to track whether the butterflies emerge in the same order they pupate.

Two caterpillars hung from the wood frame, ready to pupate. Farris said they remain there for hours in a J-shape. One straightened its body out and its antennas went limp. Moments later, it shed its exoskeleton, leaving a soft green chrysalis that would harden in hours. Farris added another piece of blue tape.

One caterpillar chose to pupate on the milkweed. Two others munched away. Farris said they would likely begin pupating by the end of the day.

As the butterflies develop, the green pupa turns very dark with visible orange and black wings.

Farris expects them to emerge around the Fourth of July. She will tag and release them in hopes that future generations will know they can come back to her milkweed.

James said it's possible. He believes the butterflies she releases will even lay their eggs on her plants.

Burd said she's hopeful for the population to continue to grow. In 2014, the Center for Biological Diversity submitted a petition to the U.S. Fish and Wildlife Service to list monarchs as endangered.

She called the popular butterflies as American as apple pie.

"Monarchs are really special to a lot of people and losing them would really be a tragedy," she said. "The best thing we as individuals can do for monarchs is plant milkweed."

For information on how to find and grow milkweed, click here.

-- Tara Kulash

tkulash@oregonian.com

503-221-8007

@kulashtara