In the mountains among the pines at an elevation of 11,000-feet, monarch butterflies roost for the winter in masses of thousands at the El Rosario Monarch Butterfly Sanctuary in Mexico. There used to be millions before recent declines. Local horticulturalist Bobbie Holder wanted to witness it for herself.

"Seeing them was magical, mystical, marvelous and magnificent," said the retired extension agent formerly with the University of Wyoming in Park County. "It was a dream come true!"

Holder ran the local annual butterfly count for a dozen years and dreamed of making the trip. The experience was overwhelming, she said.

As she ascended the mountain on horseback, the number of monarchs filling the air increased, seemingly with every stride. Butterflies would briefly land on her, then flap their iconic orange and black wings and fly away. The harmless, enchanting insects were everywhere.

If she was committed to saving butterflies before the trip, "it's ten-fold now," she said.

"Once there I realized I could never not try to help," she said. "They deserve our protection. They're so magnificent."

For anyone who has a chance at such an incredible experience, take it, she advises.

"You will come away with a more profound appreciation of nature no matter how much you appreciated it before,” Holder said. “Words can’t really express how magical it is."

You can book the trip from the states, but it's more affordable to get yourself to Mexico and book the trip from there. You can save thousands, Holder said.

Spiritual experience

Tears of joy rolled down her cheeks several times as she started to see the beautiful migrating insects surrounding the bus she caught several hours away. Once on horseback the number of butterflies increased dramatically. Then it was a short hike to the spot they have chosen.

"They look like dead leaves on the trees until you get closer," she said, struggling at times to fight back tears from the emotional experience. "It was a 1,000-foot climb, and the closer you got to the roosting spot, the more you saw, it just became more and more. It was an incredibly spiritual experience."

The Indigenous population there believe that the monarchs carry the souls of their deceased relatives back for the Day of the Dead celebrations held in early November.

"As incredible and spiritual as the miracle of nature is, it is easy to understand how they can hold such a belief," she said. “Being surrounded by thousands of such beautiful awe-inspiring creatures, I found that I had to stop several times to offer prayers of thanks for being able to witness such a beautiful sight."

The migration

Unlike many insects in temperate climates, monarch butterflies can't survive a long, cold winter. Instead, they fly thousands of miles to roosting spots in California and Mexico. Monarchs west of the Rocky Mountains travel to small groves of trees along the California coast, according to Monarch Watch, a research website founded by Orley R. "Chip" Taylor, Professor Emeritus at Kansas University. He has been documenting the species' migration and life cycle since 1992. Those east of the Rocky Mountains fly farther south to the forests high in the mountains of Mexico. The monarch's migration is driven by seasonal changes. Day length and temperature changes influence the movement of the monarch.

"Most of the monarchs joining the migration each fall are three to four generations removed from those that made the journey the previous year," he reports.

No butterfly species migrate like the monarchs of North America. They travel much farther than all other tropical butterflies, up to 3,000 miles, according to Taylor. They are the only butterflies to make such a long, two way migration every year. Amazingly, they fly in masses to the same winter roosts, often to the exact same trees.

"Their migration is more the type we expect from birds or whales. However, unlike birds and whales, individuals only make the round-trip once. It is their children's grandchildren that return south the following fall," he wrote in a press release.

Migratory monarchs that survive the winter in Mexico are 8-9 months of age and may be the longest lived of all butterflies. In contrast, reproductive monarchs breeding during the summer months only live 2-5 weeks due to the high cost of reproduction.

Declining species

During the breeding season monarchs require milkweed plants upon which to rear their larvae and nectar sources to sustain the adults during reproduction. Nectar sources are also required by the butterflies to fuel the fall migration to Mexico as well as the spring flights northward. Overwintering monarchs require shelter and water. All of these resources are diminishing. In Wyoming, only a few monarchs come through due partly to the lack of milkweed and habitat.

The few that fly through our area are "stragglers" from the migration north to breeding grounds, Holder said. Interestingly, during the 12 years of the butterfly count in the Beartooth Mountains, Holder’s never counted a monarch butterfly.

The prevalence of declines throughout all regions in the United States highlights an urgent need to protect butterflies from further losses, according to a report titled Rapid butterfly declines across the United States during the 21st century published in Science on March 6, 2025.

"Between 2000 and 2020, total butterfly abundance fell by 22% across the 554 recorded species. Species-level declines were widespread, with 13 times as many species declining as increasing," the report said.

Combining data from 35 citizen science programs across the continental U.S., the authors found declines in overall butterfly abundance over the past 20 years across almost all major regions. Two-thirds of studied species showed declines of more than 10%. Many insects have the potential for rapid population growth and recovery, but habitat restoration, species-specific interventions, and reducing pesticide use are all likely needed to curb population declines.

Holder's garden

Holder is trying to do her part to assist all of the region's important insects. One way she is helping is by growing a pollinator garden at her Cody home. She advocates others to do the same. The gardens can be easily grown and maintained and will attract many beneficial pollinating insects and bird species, which feed on the insects.

She has about a dozen varieties of grasses and about 40 different flowering plants in her pollinator garden.

"I have plants that start to flower early in the spring, and the last thing that blooms at my house will make it through a couple of frosts, so I have something blooming all the time to feed the bees and the butterflies," she said. "Maybe half or more of these plants are native to Wyoming; within 100 miles of Cody."

She very rarely uses any kind of pesticide or herbicide at her home.

"I don't ever just broad application something. It's just a spot treatment," she said.

If she has a real problem, she tries to make sure that there's water out and available and suggests spraying near or after dark, when the insects and wildlife are less active.

"I have a steady supply of butterflies to view. I have a lot of birds. I can go out in the middle of the summer and photograph 10 different kinds of pollinators within 15 minutes," she said.

She does have milkweed in the garden, a plant that can sicken livestock when they eat enough of it. Animals tend to steer clear of the toxic plants, but accidental poisonings do happen, particularly if milkweed infiltrates a hayfield and gets cut, dried and served up to livestock mixed into their hay.

Farmers really hate it, Holder said, and that's why the plant is being so closely controlled in the U.S. But the problem is, the monarch can't survive on anything else. There's a toxin in it that makes the monarch caterpillars poisonous, protecting them from predators. The only place that a female monarch can lay her eggs is on that species of plant.

"Without it, they're gone," she said.

Holder cuts back the flowers so the plants don't seed it out. She loves butterflies but obviously cares about her neighbors and the surrounding agricultural industry.

One of the first things that that people need to understand is that a pollinator garden is not just a place that feeds insects and birds. It's a home, and it needs to be a home year round, she said while running through tips on building your own garden.

She suggests planting your garden in an out-of-the-way spot.

"Nature can be a little messy. And the pollinators like it that way," she said.

Devoting an area off in the corner of the property, where you can leave things a little bit messy without it being a problem is the best plan.

The garden needs a minimum of nine flowering plants that will provide nectar and pollen spring, summer and fall. Some of the new flowers, the really showy double flower varieties, do not provide that, she said. A better option is more old-fashioned flowers, like hollyhocks, black-eyed Susans and sunflowers, that will provide resources for pollinators.

Dwarf Russian almond will be one of the first things that blooms in the spring. Asters bloom late — until a hard freeze. Globe thistle and all of the herbs, like chives, are wonderful pollinators, and fairly easy to grow. After the plants die off in the fall, she breaks the stems up and leaves them for insects that need a home during the winter.

She said because she has something blooming all the time, she has living creatures that are adding to the aesthetics of her home.

"It brings me great joy and satisfaction, and because I am quite reverent for nature, I feel a sense of satisfaction that I'm contributing to the natural world, instead of deliberately harming it."

The U.S. Fish and Wildlife Service has proposed to list the monarch butterfly as threatened under the Endangered Species Act. Protections would not apply until the effective date of a final rule. According to the most recent species status assessment, by 2080 the probability of extinction for eastern monarchs ranges from 56% to 74% and the probability of extinction for western monarchs is greater than 95%. Threats to the species include the loss and degradation of breeding, migratory and overwintering habitat, exposure to insecticides and the effects of climate change, the agency said.

The public comment period closed earlier this month.

"I sure wish we didn't have to have something endangered to understand how vital it is, but apparently, that's how our society works," Holder said. "We're going to have to ease off on having control over every square inch of the world and wanting to dominate it. Most Native American children were raised to understand that if nature died, so did they. We haven't. Our society has not instilled that in anyone. We feel like we can dominate it, and that's how we'll survive," Holder warned.