• Visitors appear very small amongst the redwood trees.

    Muir Woods

    National Monument California

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  • Ranger's tips on how to find parking

    Parking is limited. Often visitors find shoulder parking and walk on the narrow road to the Visitor Center. Read the ranger's tips on the Best Times to Visit Muir Woods. Take the Muir Woods Shuttle weekends & holidays through October. More »

  • Trail closures: Middle Green Gulch Trail and Hillside Trails access limited.

    Hillside Trail closed 10/6-8 and after 10/14 for construction and rehab. Middle Green Gulch trail is accessible from the farm, starting at the office end of the farm. Access to Middle Green Gulch is closed from the Kaasai direction during the week. More »

Butterflies

Monarch Butterfly

Photo by Marty N. Davis

Monarch butterflies add color to the forest and magic to the air. Each fall, they arrive by the thousands to a select few locations in coastal California, completing and annual migration that is unique among insects.

In the fall, Monarch butterflies throughout North American migrate to over-wintering sites in coast California or central Mexico. This migration is unique among insects. In fact, the North American Monarch butterfly is the only insect in the world known to make the same kind of annual, back-and-forth long distance migration as birds or whales.

We begin seeing monarchs in coastal California during late August and September. They are arriving from the states and Canadian provinces west of the Rockies, and each year to the same over-wintering sites, frequently even the same trees. First they gather in "bivouac sites" for a few days to a few months (depending on the weather). Some of these temporary sites are in Fort Mason, the Marin Headlands, Tennessee Valley, Muir Beach, and Stinson Beach -- all of which are within Golden Gate National Recreation Area. As the weather gets chilly (approximately October to February) they move to the over-wintering sites. Then in spring they depart, flying north and east in search of milkweed plants on which the females lay their eggs. Successive generations produce millions of Monarchs to repopulate the western states and provinces.

Monarch butterfly migration and over-wintering behavior is classified as a "Threatened Phenomenon" by the International Union for Conservation and Natural Resources due to habitat loss or degradation.

Did You Know?

Ladybugs gathering on end of log at Muir Woods National Monument.

Every year Convergent Ladybugs migrate to Muir Woods from California’s central valley seeking the cool refuge of the redwood forest. You can see them resting in large clumps on plants and fence posts.