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Mama Monarch arrived on June 28. She spent a full week laying eggs on my milkweed. As I watched her, she told me to move aside as she had 400 eggs to go.

Monarch moms lay 500 to 600 eggs a week, and then they die. Their lifespan is short, about six weeks. As she laid the eggs, I collected as many as I could.

Monarchs are one of the few invertebrates to migrate each winter. Most invertebrate creatures go into a pupa or cocoon stage and emerge in the spring to start their cycle of life again. In winter, monarchs are in a phase known as diapause. During this stage of their lives, they live mainly on their fat deposits. They do not mate.

So where do they go in winter? The eastern populations return from Canada and fly to Michoacan, Mexico, overwintering in the high mountains. The western population return from Canada and fly to the Bay Area and as far south as Baja California.

From tagging, we know that some western monarchs do fly over the mountains and join the easterns. These are the wrong-way monarchs. They are all the same species.

The eggs I collected have hatched and are in jars munching away on milkweed leaves. They have eaten their own shells and, I fear, some other shells also. They keep shedding their skins and growing larger.

Many do not make it through this stage. They may be eaten by their siblings or not able to shed their skins properly. In the wild, only a tiny percentage reach adulthood. With hand rearing, the results are better. The milkweed that monarchs eat makes them taste bad to birds, but that does not deter spiders, wasps and lizards.

Last February, I joined a tour group visiting Mexico City and then going to view the monarchs in their wintering area. I was the only non-Texan in the group. We spent a few enjoyable days in Mexico City, then took a small bus to the area in Michoacan where the butterflies spend the winter. All the wildflowers were in bloom.

We stayed at a former hacienda that had been turned into a beautiful hotel. The next morning, we started up the mountain and visited the headquarters. There, we changed to small horses and a guide led us farther up the mountain.

Water was flowing down the mountain as we went up, and the trail was full of mud and water. We reached a high plateau and then began to see the monarchs. They were feeding on the wildflowers in the forest. Butterflies were in the air all around us, and the weight of them was pulling tree branches down. Whole trunks of trees were covered with them, their bodies close together to keep warm.

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They had started to breed again, and dead and dying males were on the ground. Only the females make the long journey across Mexico and up into Texas, where they lay their first eggs. They stay in the mountains until mid-March, then start their long journey. We were told that they move daily in those forests from site to site. I think they must be following the native flowers.

It is an inspiring sight to see all the golden bodies floating in the sun. I don’t know how scientists could count the number overwintering as there are millions. Many locals came up the mountain and World Wildlife Fund had a representative there. The trail up and down the mountain is not for the faint of heart because it is steep and muddy both ways.

This monarch migration is one of the most amazing migrations in the natural world. If you want to help monarchs survive, then plant flowers that bloom for months and grow milkweed to help them on their journey.

Workshop: UC Master Gardeners of Napa County will host a workshop on “Growing Winter Vegetables” on Saturday, Aug. 26, from 9:30-11:30 a.m., at UC Cooperative Extension, 1710 Soscol Ave., Napa. Enjoy fresh vegetables from your own garden during the fall, winter and early spring when fresh greens and vegetables are truly welcome. Soil preparation, sunlight and temperature requirements, when and how to plant, watering, fertilizing, pest management and harvest tips will be discussed. Online registration (credit card only) Mail-in form (cash or check only).

— Do you want to become a UC Master Gardener of Napa County volunteer?

To obtain an application you must attend an information meetings. For meeting dates, location and times or to learn more about the program and volunteer commitment, visit the UC Master Gardener of Napa County website.

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UC Master Gardeners of Napa County ( answer gardening questions on Monday, Wednesday and Friday, 9 a.m. to noon, at the UC Cooperative Extension office, 1710 Soscol Ave., Suite 4, Napa, 707-253-4143.