Banding Butterflies

“We’re holding you all to secrecy about this location.” The entomologist stood, blocking the doors of the stopped bus, to get our attention. I looked out my side window to see a beautiful sunny day, and out the front towards a shaded grove of tall eucalyptus trees. We were somewhere along the West Coast between the Los Angeles County Natural History Museum, where we had started our trip, and Refugio Beach, north of Santa Barbara, where the Coast Highway turns inland.

As part of my donation to the museum I had offered to spend this Saturday helping to band monarch butterflies. I didn’t have a clue what I had gotten myself into. How do you band a butterfly?

Seven or eight participants who seemed to know exactly what they were doing had already slipped past our leader and down out of the bus. He continued: “Follow me to the clearing where I’ll explain what you will be doing.” About twenty of us newcomers gathered with him at the edge of a ravine that ran through the trees, where there were several huge, fallen logs. He motioned for us to sit on them to listen and watch.

Catching and banding monarch butterflies
Catching and banding monarch butterflies

Some of his helpers were laying out huge butterfly nets attached to the ends of twenty-foot-long poles. Others were placing tall extension ladders against the trunks of eucalyptus trees. A few men were climbing the ladders and gently gathering into their nets clumps of what looked like dead leaves, but instead turned out to be hibernating monarch butterflies. One woman was preparing the materials for banding, and then she started registering into her record book all the information for each butterfly.

The entomologist described and then demonstrated how we would pick up a butterfly from out of a net with one hand while holding the banding label with the thumb and forefinger of the other. The bands were not bands at all. They were paper labels, one inch wide by a quarter of an inch long, sticky on one side. Printing on the other side requested the finder to phone our museum’s 800 number and tell the operator the date and location where the butterfly was found.

We were to carefully pick up the butterfly by the thorax, and “band” it by folding the label over what I named “the shoulder of the right wing,” then call out to the woman with the record book, giving her the identifying number printed on the band, the sex (males have a black patch of sex-scales on the hind wings), and a number from one to five describing the condition of the insect—one being pristine, and five being shabby, such as having been bitten by a lizard. Finally we would reach our hand up high, open our fingers, and the butterfly would float away.

Putting a band on a monarch butterfly
Putting a band on a monarch butterfly

Soon the air was filled with butterflies. Ethereal shadows of the forest trees, sprinkled with spots of sunshine and filled with hundreds of silent, fluttering wings, enveloped us. The quiet was calming and everyone was working steadily. For two or three hours we banded the monarchs. It was a magical, unworldly sensation.

What I learned that day was that these particular monarchs wake from their winter hibernation in the spring, mate, and then fly south to a large forest in Mexico located just north of Mexico City. There they find native milkweed plants and the female lays her fertilized eggs, attaching them to the underside of milkweed leaves. The eggs mature, hatch into caterpillars which eat their sheltering milkweed leaves, and within a few weeks grow large. When full-sized, they start to spin their cocoons, fastening themselves again to the underside of the leaves. Each caterpillar metamorphoses into a butterfly in about two weeks, and then breaks its way out of the cocoon.

Surprisingly, these new butterflies later fly north, even though they have never been there, to the very same eucalyptus grove where their previous generation had hibernated the year before. They then find a branch to cling to, and go into their own winter hibernation.

When the entomologist gave the sign, we cleaned up our site, stored our equipment back on the bus, and headed back towards the museum. All the way home I enjoyed a glow, having been an observer and participant in this miracle.

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