Arizona doesn’t get swarms of monarch butterflies migrating between their summer habitats up north and the mountains of Mexico where they spend the winters, but they are a dependable presence.
The Southwest Monarch Study, which enlists citizen-scientists to tag migrating monarchs in an attempt to better understand their migration, tags thousands a year.
“Where they come from is anyone’s guess, but they do fly in from the north,” said Gail Morris, coordinator of the Southwest Monarch Study. “We tag 2,000 to 3,000 every year. Imagine all those we haven’t seen,” she said.
This year, her group has teamed with Borderlands Restoration to grow native, pesticide-free milkweed varieties in a greenhouse near Patagonia, Morris said.
The Canelo Hills south of Patagonia and the entire Sonoita area are hot spots for monarchs, she said, though they are found throughout the state, including Grand Canyon National Park.
They make an annual appearance at the Arizona-Sonora Desert Museum, said Howard Byrne, a horticulturist there who has been trained to capture and tag them.
This year has been particularly good, he said, with more than 20 monarchs.
Byrne said the monarchs usually leave in late fall, but some are still around this February because of the warm weather.
Arizona has one known “overwintering” site, along the Salt River in Phoenix.
While the populations are not large, Arizona is “in a pivotal position” for helping to rescue the migratory phenomenon, said ethnobotanist Gary Paul Nabhan, who is spearheading the “Make Way for Monarchs” drive.
Fifteen years ago, when he began writing about the importance of pollinators, nobody thought monarchs passed through Arizona in significant numbers, he said.
Now, with the tagging programs, scientists know they pass through and end up in Kino Bay, Sonora, in the mountains of Mexico and in California, he said.
Arizona is also home to 20 varieties of native and pesticide-free milkweed, he said, a crucial element in habitat restoration.
Arizona is also leading in habitat restoration, he said. Nabhan said 10 farms and ranches in Southern Arizona have adopted pollinator-friendly practices.