Guest Written by Author Claire Datnow.
It’s one of nature’s biggest mysteries. Every year, a super generation of monarch butterflies—which lives eight months longer than other generations of monarchs—migrates to one specific location: the Monarch Butterfly Biosphere Reserve, nestled in the majestic oyamel fir forests in the central mountains of Mexico. As many as one million butterflies from wide areas of North America fly to the reserve, a place that they’ve never seen. The trees seem to turn orange, branches bending under the collective weight of thousands of monarch butterflies.
In my book Adventures of the Sizzling Six: Monarch Mysteries, jovial science teacher Mr. Ernie Fix describes this phenomenon to his class:
‘The monarchs will live here [at the Biosphere Reserve] until the spring comes and mating can begin,’ Mr. Fix says. ‘They must wait for spring when the milkweed starts to grow in the United States and southern Canada. The milkweed provides a place for monarchs to lay their eggs. When the eggs hatch into caterpillars, they will feed only on milkweed and no other plant.’
Monarchs make the trip to the reserve once in their lives, some navigating as much as three thousand miles to a tiny point on a map. For more than ten thousand years, these monarchs, each weighing no more a paper clip, have traveled without a map, a compass, or GPS. How do they know where to go?
Scientists have devoted years to studying monarchs, unraveling part of this mystery: these butterflies are guided by the position of the sun. It’s pretty miraculous if you think of the monarchs as tiny, orange solar compasses with wings.
After wintering in the mountains for eight months, when the temperature starts to warm the monarchs begin their return journey, traveling as far north as Canada. When summer ends, the monarchs migrate south again—and so the cycle of life keeps on turning, like a giant Ferris wheel, through the seasons.
Unlike the migrations of other insects, four successive generations of monarchs are born and die within two to three weeks along the way. The fourth generation to hatch, known as the super generation, is bigger than the previous three generations and can survive for eight months in the mountains.
The monarch butterfly isn’t just fascinating—it’s essential. Without pollinators like monarchs our agriculture and food system would collapse. The US Fish and Wildlife Service (UFWS) estimates the North American monarch population has dropped over 90 percent since the 1990s. In December 2020, the UFWS announced that listing monarchs as a threatened and endangered species is “warranted but precluded by work on higher-priority listing actions.”
One conservation concern for monarch butterflies is illegal logging in the reserve that destroys their winter habitat. Their food sources are also disappearing in the US because some farmers consider milkweed a weed and spray it with insecticides.
It’s now more important than ever for us to protect these natural wonders! The best thing we can do is plant native milkweed. It’s a great way to learn about nature. Click here for other conservation tips.
Teachers and Educators: Visit my website for a FREE handout with role-playing cards featuring characters from Monarch Mysteries.