Courtesy photo The eastern monarch butterfly population doubled in population size by acre during its hibernation in Mexico. Experts say it’s a good sign, but the population is still below average even with the increase.

ESCANABA — The eastern monarch butterfly population nearly doubled in 2025, but the numbers remain far below the long-term average.

According to the World Wildlife Fund (WWF), The population wintering in central Mexico’s forests occupied 4.42 acres, up from 2.22 acres during the previous winter.   Scientists attribute the increase to better weather conditions throughout 2024, as it was a less severe drought year than in previous years.

The survey is conducted by WWF-Mexico and Mexico’s National Commission of Protected Natural Areas in collaboration with local communities.

The organization has data going back to 1993 up until 2025.

The butterflies are no strangers to the local area. The Stonington Peninsula is a stop off point on the migration route south.

The population saw its largest occupation from 1996 to 1997 when the butterflies occupied 44.95 acres.

The lowest occupancy occurred from 2013 to 2014, when the butterflies occupied a mere 1.66 acres.

The data indicates the occupancy rate fluctuates each year, rising and falling. However, acre occupancy has not reached double digits from 2018 to 2019, with 14.95 acres. Before that, the occupancy rate last reached double digits from 2008 to 2009 with 12.50 acres.

The butterflies are currently on their journey back from Mexico, migrating north.

The butterflies make their journey every year at the end of summer, migrating from Canada and the Northern United States to mountain forests in Mexico. After winter, the same butterflies migrate back north, laying their eggs on milkweed plants, typically in the hundreds.

The monarch butterflies that are in the U.P. during the summer have a short lifespan — around two to six weeks. In contrast, the migrating generation lives for six to nine months.

The butterflies that made the trip down will not make it back, but their offspring will.

The mature monarchs lay eggs in the south and then die.

Their offspring continue to head northward and, by the end of April through May and early June, are the ones seen in the U.P. at that time. Two more generations hatch, breed, and die in the north in the summertime. The third generation stops at the Stonington Peninsula on their way south.

Sue Jamison, who coordinates the tracking efforts at the Stonington Peninsula, weighed in on the current population. Jamison has been involved with the Monarch Project on the Stonington Peninsula for over 25 years.

“They have occupied almost twice as much of the area as they did last year, but that is still very much below the average of what it has been in past years,” she said.

She said it’s a good sign that the population is increasing but still well below average.

“It has doubled, but you have to take into consideration that that’s one year, and when you look at the past years, there had been a lot more,” Jamison said.

Jamison explained why the population is below average again, pointing to three factors: habitat loss, insecticides, and climate change.

She explained the monarchs rest in oyamel trees in Mexico, similar to the cedar trees in the U.P., but illegal activity has limited the amount of oyamel available.

“The monarchs need those for protection, and there has been a lot of illegal logging down in Mexico,” she said.

“But many people now are, in Mexico, are really trying to help the monarchs and just save those wintering grounds.”

She said the use of insecticides on milkweed, which is the only plant the larva will feed on, is also a contributing factor to the low population.

“That’s their only food source,” Jamison said.

She said the monarch is resilient, but warmer temperatures in Mexico during their wintering period affect the migration patterns.

When monarchs are wintering, they stay in the forests where the temperatures are cold enough to slow their metabolism but not so cold that they will freeze to death.

“With climate change, sometimes the weather is too warm, and so that’s affecting their overwintering patterns with the temperature. So those three, climate change, habitat loss, and insecticides are the three factors that are affecting monarchs right now,” Jamison said.

She acknowledged the increase in acre coverage and attributed that to the more recent efforts of individuals and organizations in Mexico working to preserve the forests where the monarch winters.

“They’re diligently working on saving those areas,” she said.

“We recognize the key role of local communities, as well as the support of the government of Mexico in conserving the forest and providing this iconic species with the opportunity to thrive,” said Jorge Rickards, director general of WWF Mexico. “It’s now time to turn this year’s increase into a lasting trend with an all-hands approach where governments, landowners, conservationists, and citizens continue to safeguard critical habitats along the monarch’s North American migratory route.”

Local residents in the U.P. can help the monarch population by letting its favorite plant, milkweed, grow.

Milkweed Is a native herbaceous perennial that appeals to butterflies, especially the monarch, as it is the only plant a monarch larvae will feed on.

“Once milkweed is planted, once it has a spot to grow…. It will multiply, it will spread,” she said.

Jamison added that she noticed that the milkweed in local areas is being allowed to grow.

“It’s crucial to have (and) to save as much milkweed as we can,” she said.

Each spring, Bay College hosts a plant sale and sells milkweed plants.

The plant grows in various areas, including farmlands, agricultural areas, and even on the side of the road or within the median.

“There’s milkweed growing in between Rapid River and Gladstone. As you’re driving, that grassy median area there has quite a bit of milkweed growing in it that you can notice during the summer months,” Jamison said.

Besides milkweed, Jamison recommends planting nectar flowers for the adult monarchs to feed on.

“Those are really the two biggest things that an ordinary citizen can do,” she said.

WWF echoed Jamison’s call to help maintain the monarch population, saying they are a key contributor to ecosystems.

“As pollinators, monarch butterflies contribute to healthy ecosystems across North America. With 80% of agricultural food production depending on pollinators like monarchs, protecting them helps us all,” according to the WWF.

Jamison is part of the Monarch Project and monitors monarch larvae in the summer months.

“We have two fields near the lighthouse (Stonington), and that happens all summer long. We have a great group of volunteers of people that are really passionate about monarch butterflies and want to help,” she said.

She recognized the efforts of the volunteers as well as the support of the local forest service and Wildlife Unlimited.

“Those are two that have really helped us,” she said.

Jamison said the increase in the population is a good sign, but there is still more work to be done.

“There’s still hope, and like I said, the monarch is very resilient, and if we can do some things to help, hopefully, you know, this this next season will be good, numbers will increase.

But like I said, I’m very happy that more and more people are becoming aware,” she said.

She added that she encourages others to spread the word about the monarch, saying it’s essential to get more people interested.

Jamison and volunteers will begin roost counts during the third week of August at the Stonington Lighthouse.