Flight of the monarchs
Monarch butterflies reared and released by people in Southern Oregon last month are migrating south, and through tags attached to their wings they are providing data about the mysteries surrounding these threatened insects.
As the butterflies migrate from the Pacific Northwest to their overwintering sites in California, people often notice them resting or feeding on flowers and trees.
Some notice the sticker affixed to a butterfly wing — complete with I.D. number and an email address. And some of those people have been taking photos and reporting the butterflies’ whereabouts to the tagging program supported by Washington State University, explained Robert Coffan, chair of Western Monarch Advocates and co-founder of Southern Oregon Monarch Advocates.
“They surprise us. Someone from Ruch released a butterfly, and someone in Trinidad, California, on the coast, in the fog, found it,” he said.
Aside from a few anecdotal stories, researchers previously believed it was too cold for the butterflies to migrate along the coast.
Photos of five butterflies from the roughly 2,000 tagged and released in Southern Oregon have been received so far, said David James, associate professor of entomology at Washington State University.
“The number of monarchs we tag is just a drop in the bucket of the population in the area, probably 1% to 5%,” James said. “And for every 200 we tag, we can expect just one or two to be recovered, about 0.5% to 1% recovery rate.”
Normally by this time of year, almost all the butterflies would be on their way to their overwintering sites, Coffan said. But as many Southern Oregon residents have noticed, some monarchs are still flitting through local gardens.
The anomaly, researchers estimate, is due to this year’s bright, hot October.
“They’re smart critters. Life is still good here, it’s still warm, there’s still nectar,” he said. “But every year, we have some that finally leave pushing November.”
Coffan has a couple of monarchs still in the chrysalis stage, and he may be releasing them all the way up to Halloween. One looked as if it would be ready soon, he said, and he planned to enlist the help of local third graders to help with the release.
“But we’re at the mercy of the insect, when they decide to emerge,” he said. “The thing that always amazes me — that I like telling the kids — this insect has never in its life flown before, and in a second, they fly; they’re gone.”
Unlike its fellow monarchs to the east of the Rocky Mountains, the western monarch population is hovering just above being classified as critical — not yet endangered, Coffan said.
“If you look at a map of the United States, west of the Rocky Mountains, anyone who sees a monarch, that’s our western monarch population,” he said. “Right now, everyone is jazzed about the resurgence of our western monarch.”
Recent population counts of the insects have been cryptic. In 2018, the western monarch population was estimated at fewer than 2,000, he explained.
But the 2021 count found 246,000 monarchs.
Researchers still don’t completely understand how the butterflies disappeared and reappeared in such numbers.
This year’s tagging program hopes to illuminate some of what Coffan described as a wonderful mystery we humans still have so much to learn about.
Unlike their eastern kin, western monarchs don’t usually migrate to Mexico but to Southern California, areas such as Monterey Bay or Santa Cruz. Their overwintering sites are not threatened by deforestation as in Mexico but by land use changes and pesticide use.
“We kind of compete with the monarchs for that land; it’s where the Beach Boys sing,” Coffan said.
Butterflies there are found in places such as eucalyptus trees in parking lots, he said. Creating habitat to support the monarchs doesn’t require monocultures; they need weigh stations of milkweed and plants that bloom and flower with nectar for a long time.
“Milkweed is the only host plant to support those chubby caterpillars. It’s all they can eat. It’s the only place monarchs will lay their eggs,” he said.
It’s important to ensure the plants are grown without pesticides, he said. Long-blooming plants can provide nectar for the butterflies throughout their entire period of breeding in the summer, helping feed them as they travel on their long journey, some as far as 400 miles in a matter of weeks.
To watch the flight of the monarchs across the country, see the Xerxes Society’s Western Monarch Mapper page, populated with monarch sightings throughout their migration, at monarchmilkweedmapper.org/.
To learn more about local monarch efforts and see photos of monarchs snapped during their migration, see somonarchs.org and facebook.com/somonarchs.
Reach Mail Tribune reporter Morgan Rothborne at firstname.lastname@example.org or 541-776-4487. Follow her on Twitter @MRothborne.