Sky King : 150 Volunteers Help Researchers Study the Migration of the Monarch

ABOUT NOW, hundreds of thousands of monarch butterflies are gathering in sheltered groves along the Pacific Coast for the winter, having migrated from beyond the Continental Divide. The familiar monarch is described as having reddish-brown wings; but to me they look dark orange, amber and pale yellow, like an art nouveau lamp. The colored areas are divided by black veins, and the edges are black with two rows of white spots. They are among nature’s loveliest creatures.

There are perhaps 100 winter roosts from Mendocino County to Baja California. Many are eucalyptus groves, where the monarchs cling to low branches or carpet the undergrowth like leaves, only the drab undersides of their folded wings showing.

In California Scenic magazine, Gary Wolfe (with Christopher D. Nagano) writes poetically of these groves: “The air is saturated with the cool moisture of the sea; the fresh smell of eucalyptus envelops the wooded landscape; thin, pale mists of fog drift past in the upper boughs on barely perceptible breezes. Under the clouds, nature’s colors are softly muted.”

Occasionally what appears to be a leaf will open to display the monarch’s full beauty. Some of the butterflies detach themselves from the wintering colonies, flying to nearby fields to drink dew or nectar. Others return. “The movement of the butterflies, some departing, others returning to their clusters, creates a surreal effect. The sight of thousands of these elegantly marked insects bobbing, soaring and pirouetting is enchanting: The image seems to come straight from a fairy tale.”


In recent years these winter retreats have become endangered by urban encroachment, herbicides, pesticides, polluted air and reckless tourists. Many responsible state, national and even international agencies have sought to protect the winter roosts, but Nagano reminds me, in a letter, that “the American bison and the passenger pigeon were once among the most abundant creatures on earth.”

By March, the monarchs have mated and leave for the inland regions. They seek out milkweed, where they will lay their eggs; the monarch’s caterpillar feeds only on the milkweed.

It is a poignant fact that the monarch makes this epic two-way journey but once in its lifetime; after laying its eggs, the butterfly dies, and the following autumn its westward flight is undertaken by its great-great-grandchildren, guided, evidently, by a biochemical compass. The generation that winters here lives several months in semi-hibernation; its offspring live but two.

Nagano, a research associate in entomology at the Natural History Museum, is conducting a study of the monarch’s migrations and working with various agencies to effect its protection. Aided by 150 volunteers, from entomologists, park rangers, amateur naturalists and high school biology students, the museum has placed tiny adhesive-paper tags on 59,000 individuals, chiefly in California coastal colonies; 500 tagged monarchs have been recovered, mostly at the groves where they were tagged. All were sent in dead. They were found by hikers, golfers, gardeners, senior citizens and schoolchildren. Some were removed from auto bumpers or caught by cats.


Writing in Terra magazine, Nagano and Naomi Wolfe note: “Monarchs have been mailed to the museum in every possible container. Most were placed in an envelope, often wrapped in tissue paper or plastic wrap. Some were packed in sturdy jewelry boxes, while others were sent in oversize cardboard boxes securely padded with Styrofoam.”

Evidently it is not possible--or certainly not easy--to capture a live butterfly and send it live to the museum. But I wondered how Nagano and his helpers tag the live ones in the first place. As a child I heard that if you touched a butterfly’s wings and rubbed off that magical powder, they couldn’t fly anymore and would die.

I asked Nagano. “Kindergarten stuff,” he said. Actually, the wings are like plastic membranes covered by myriad colored scales. The entomologist nets the butterfly, rubs off a tiny patch of scales and applies the adhesive tag. Then the butterfly is freed.

If you catch a tagged monarch, send it to the museum with a note saying when and where you caught it.

Of course if you can read the tag, you don’t have to catch the butterfly.