After rough skies, monarch butterfly population on the rise

Monarch butterflies are making their 3,000-mile migration to central Mexico after spending the warm months in much of the United States — including Minnesota. In 2024, the there was talk of the pollinator being named a threatened species. However, this year the population increased by 64 percent, according to the World Wildlife Fund.

“This seems to be a pretty good year for monarchs in their migration,” Erik Runquist, conservation biologist with the Minnesota Zoo told MPR News. “A lot of times, you can tell a migrating monarch, will be about 20 to 30 feet up, kind of drifting southward this time of year.”

Roughly four generations of monarchs are born in Minnesota every summer. Each generation lives for about four weeks except the last generation. The last in the brood survives for approximately six months to make the journey to Mexico where they overwinter.

“This is the super generation that will migrate from here and even southern Canada all the way to central Mexico, and so this is a really magical time,” Runquist said.

Conservationists estimate how many monarchs are out there by counting the number of acres of trees where they rest in a semi-hibernation state over the winter. They won’t know how strong the 2026 brood is until late winter or spring when they are able to take the measurement.

“Monarchs are very good indicators of environmental health and ecological health,” Runquist added. “They are very sensitive to small changes in the environment, and so we can use these flagship species like monarchs or other insects and track their populations.”

“When we see more of them, that's probably a good indication that we are doing well, or at least the conditions have been well.”

Runquist says there are a number of reasons for seeing increased numbers this season — some, even spurred by humans.

“Some of it is weather year over year, but also it is concerted efforts to try to help monarchs in our own yards,” he said. “There is a real collective love of monarchs, and the actions that we can be doing as a group are helping.”

While weather is an important factor to the strength of the monarch population, having enough food is also crucial to expanding over generation. Monarch caterpillars eat the leaves of milkweed and adult butterflies drink nectar from a variety of flowers including meadow blazing star.

“We do encourage people to plant in their backyard, no matter the size of the habitat space you have available,” Monarch Joint Venture Executive Director Wendy Caldwell said. “The more often we can help those butterflies in the wild encounter milkweeds, the more reproductively successful they’re going to be.”

“If conditions are really good, they have high potential to produce a lot of butterflies to produce a lot of individuals” she told MPR News. “If it’s a good year for growing crops, it’s generally a good year for growing insects, and so monarchs are like that.”

While increased numbers are a good sign — the growth needs to continue over time to build up the population.

“We need to see that sustained through time,” Caldwell said. “So even though we’ve seen increases the last couple of years, we still want to see that population sustaining at about double where it was last year.”

Monarch Joint Venture is a Minnesota-based national nonprofit focused on pollinator conservation.

“One in every three bites of food is thanks to a pollinator, and if we if we lose our pollinators, we're going to lose the diversity of foods that we eat every day,” Caldwell said.

“We can’t live without pollination in the world we live in,” she added. “There’s a lot of artificial ways to do things, but perhaps not at the scale that we need them to.”

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