The Pismo State Beach Butterfly Grove stakes its claim as the largest monarch butterfly grove on the West Coast. Each year when it begins to get cold, the monarchs begin a migration of up to 2,500 miles, from as far north as Canada to as far south as Mexico. A smallish grove of eucalyptus trees on the Central Coast’s Pismo Beach is one of their stopovers.

The butterflies are in residence roughly from late October through February. They cluster on the trees and hang by the thousands in thrilling orange curtains.

Recently, I spent the weekend with some friends in Santa Maria. On Sunday morning we headed up to the grove. For a minute, I couldn’t see what the fuss was about. Where were all the butterflies? Why weren’t they floating about our heads and dazzling us?

Then I looked through one of the available telescopes, I saw the well-camouflaged monarchs lounging in the trees and began to discern the almost unbelievably large clusters, many feet long, hanging here and there high up in the eucalyptus branches. As of Dec. 2, their number was estimated at 20,000.

From the down-home placards, I learned all kinds of interesting things:

Monarchs use their eyes, feet and antennae to find milkweed. It is the only plant they will lay their eggs on.

A monarch butterfly glues her eggs to the milkweed leaves.

Each egg is the size of a pinhead, is off-white to yellow and features longitudinal ridges that run from the tip to the base. The effect is of a Noguchi lamp.

In about three to four days, a tiny caterpillar hatches from the egg.

The caterpillar (larva) wears a smart suit of thin stripes: lettuce green, ivory, and jet black.

After the 15th day, the caterpillar hangs down from stems or leaves in the shape of the letter J.

The caterpillar outgrows and sheds its skin five times. After shedding its final skin, the caterpillar develops a green and gold chrysalis. Inside the chrysalis, it continues to change into a butterfly.

The chrysalis is a neatly wrapped package that tightly swaddles its cargo. As the days pass, the chrysalis becomes translucent.

About two weeks after the chrysalis is formed, the monarch emerges.

After the monarch leaves the chrysalis, it pumps fluid from its abdomen into its crinkled wings to expand them.

Much as in the human world, in the mating process, the successful male grasps the female and flies her to the trees.

Clustering behavior is thought to protect the butterflies from wind, rain and predators.

Monarchs are tagged to help us understand how far and in which directions they fly.

Males have a black spot on each of their lower wings. The black veins that run through the orange parts of their wings appear to be thinner than those of the female.

Females have thicker dark veins that run through the orange parts of their wings.

The Pismo State Beach Butterfly Grove website explains: “The butterflies form dense clusters with each one hanging with its wing down over the one below it to form a shingle effect. This provides shelter from the rain and warmth for the group. The weight of the cluster help keeps it from whipping in the wind and dislodging the butterflies.”

No one seems to know why they use milkweed, or why only the milkweed, nor how the butterflies know how to return to this particular grove, nor specifically why they choose to congregate in such fantastic, draping clusters.

Maybe they just get a kick out of seeing hordes of humans below, craning their necks, aiming their cell phones and mostly stunned into silence.

It’s always hopeful to observe the powerful reduced to silence by the small, the vulnerable, the powerless, the beautiful. In fact, I enjoyed the reverence and awe of the onlookers, including my own, almost as much as I enjoyed the miracle of the curtains of monarchs.

A couple of friendly and knowledgeable docents patiently fielded the questions of onlookers.

How much does a monarch weigh? Less than one gram.

How long does a monarch live? The monarchs that visit Pismo Beach are a special variety. They have a lifespan of six months as opposed to that of common monarchs, which live only six weeks. However, even with an extended lifespan, those butterflies that leave in March will never return.

How many eggs do monarchs lay? Typically, more than 1,000 eggs in their lifetime.

During the season, the docent trailer opens at 10 a.m. and closes at 4 p.m. daily. Daily talks are given at 11 a.m. and 2 p.m., weather permitting. Western Monarch Day is Feb. 4, and the season ends this year on Feb. 27.

Afterward, my friends and I motored further up the coast, to San Simeon. Here, we spent a happy hour watching the elephant seals, whose mating habits are significantly coarser than those of the monarch butterfly — but that’s another story.

Let’s get away from our computer screens more often and explore some of the mysteries of our wondrous state!

Heather King is a blogger, speaker and the author of several books.