It’s been a rough year for the migratory monarch butterfly. The colder spring in the upper Midwest negatively impacted population numbers and the butterfly was classified as endangered by the International Union for Conservation of Nature (IUCN) on July 21.

One of the leading research nonprofits on monarch butterflies out of the University of Kansas, Monarch Watch, led by its director and professor in the Department of Ecology and Evolutionary Biology, Dr. Orley “Chip” Taylor, has been closely tracking the migratory monarch population since 1992.

While this IUCN designation won’t impact U.S. policy, Taylor questions the scientific basis for why the classification was made now in the first place. He theorizes that the designation is based on long term threats.

“There are significant risks to monarchs both from habitat loss and climate change,” Taylor said. “Global conditions are changing very rapidly. Those global changes that have occurred in the last 25 years have had a major impact on monarch butterflies at the overwintering sites.”

Migratory monarchs make the trek from southern Canada and the northern Midwest starting in late August to get to Mexico, where they spend the winter. In February, they begin traveling north again.

However, the butterflies that migrate to Mexico are not the ones that arrive back in Minnesota in the spring. Migratory monarchs go through several generations before the descendent of one that wintered in Mexico makes it up north.

There have been four major “winter kills” in Mexico in recent history that have resulted in a 60-80% loss of the population, which Taylor correlates to the rising temperature of the Pacific Ocean. He said there hasn’t been an extreme loss like this since 2016, but cautions that there “could be an event like that any year.”

“It used to be like hundreds of millions of butterflies that would end up down there and now they’re seeing closer to like 10s of millions,” said Farm at the Arb Education Program Coordinator at the Minnesota Landscape Arboretum Ping Honzay. “It’s tricky because the numbers fluctuate year to year in general, just the same way, like, deer populations fluctuate.”

Taylor worries that if we go into the winter with a low population, such as this year, and have a “winter kill,” it would take years for the population to recover.


In order to help the migratory monarch population thrive, dedicating garden space to milkweed and other pollinator plants is key. Monarch Watch’s Monarch Waystation Program encourages people to plant milkweed and other nectar sources in their gardens and register it online to keep track of areas that may need more waystations than others. Across nine countries there are over 40-thousand registered waystations.

“That’s a good start, but we need about four million,” Taylor said. “We need to concentrate on the area from Madison, Wisconsin, across to the central Dakotas. That’s the biggest area from which monarchs get to Mexico. Seventy percent of the monarchs come out of the upper Midwest.”

Tony Gomez founded a blog called Monarch Butterfly Garden to provide information for those in Minnesota and around the U.S. on how to start a butterfly garden, reliable local garden centers, the best plants for monarchs and more.

Gomez’s advice for starting a garden: “Don’t get overwhelmed, start small. Establish the native plants first, it’s a process… I think gardeners are going to have a lot to do with how the monarch fares in coming years.”

Honzay recommends frequenting local independent garden centers for pollinator plants to guarantee low pesticide use and more plant varieties. She worries that, due to the many steps in the supply chain, larger garden centers may say they don’t use neonicotinoids — a class of pesticide used in farming, lawn care and tick and flea prevention products — but actually have no control of it in earlier stages of production.

“What I try to tell people is if you’re not making your living off of the plants that you’re growing, as much as you can, just be okay that you may have some holes in your plants,” Honzay said.

Gomez warned that some pesticides that say they are safe to use in gardens do not include caterpillar populations, which can die from ingestion.

Honzay encourages gardeners to ultimately plant what they want to take care of and to utilize the arboretum as a resource for deciding what plants would work best for their space. Common milkweed, swamp milkweed and butterfly milkweed are Honzay’s personal monarch-friendly favorites.


Another way to help a new generation of butterflies is to take part in the educational experience of watching the developmental stages of a butterfly.

Whether it be from catching caterpillars in the garden or ordering a kit online, it’s best to keep butterflies in all stages of development in a breathable habitat that experiences natural light and temperature changes, such as a screened in porch. Providing enough space, fresh food and keeping the cage clean is essential.

Caterpillars and adults could be kept separate to avoid certain diseases that may come from the close contact.

Taylor recommends using a live plant as the food source, or changing out cuttings frequently, as it’s “the best way to ensure that the butterfly will be strong enough to make the migration.”

“It’s good to keep them for 24 hours and then release them because their wings need some time to harden,” Honzay said. “Then you should let them go as soon as you can because they do want to be out and they can actually batter their wings.”

Taylor also encourages those raising monarchs to tag them before release. Tagging monarchs with coded stickers is a “large-scale community science project” that Monarch Watch runs to help track the probability of butterflies reaching Mexico based on the geographic location from which they start, the timing and pace of their travels and mortality during migration. One percent of tags are recovered, and while this may seem low, according to Taylor, this is quite high.

According to Honzay, in 1975 a local science teacher, Jim Gilbert, tagged a butterfly at the arboretum with a couple of students and it was the first one ever recovered in Mexico.

“The kids wonder a lot about if it hurts them and I’ve heard it compared to the weight of a shoe on your foot,” Honzay said.

It’s best to tag monarchs in the Twin Cities region in late August/early September as any butterflies that developed before then are not likely to make it to migration.

“The monarchs that are going to migrate are actually biologically different from monarchs that are coming out midsummer, because they need to be a little bit bigger and have fat stores to make that journey,” Honzay said.

While there are other butterfly species in Minnesota that are on the U.S. Federal Endangered species list, Honzay sees monarchs as “ambassadors” for other butterflies.

“The monarch is so much better known and lots of things that are threatening the monarch are also things that are threatening other butterfly species or other pollinators,” Honzay said.