All Trails at Muir Woods are Open. Green Gulch Trail at Muir Beach to Close
The Green Gulch Trail from Kaasi Road will be closed for restoration construction on the weekdays from 7 AM - 4:30 PM beginning early August through October 2014. Full trail access will be available during evening hours and weekends. Signs will be posted. More »
7 Ranger's Tips on How to Experience Muir Woods Safely This Summer or How to Find Parking
Summer is the busiest for Muir Woods. 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. On weekends & holidays, take Muir Woods Shuttle More »
Ride the Muir Woods Shuttle. Summer is the busiest time for Muir Woods. Parking limited.
Muir Woods is experiencing high numbers of visitors. Summer traffic and unsafe parking behaviors are adding stress to visitors and residents. Expect delays on Hwy 1 as people drive to and from Muir Woods and local beaches. Read 7 Ranger's Tips on Parking. More »
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?
Fires over the centuries can hollow out a redwood, burning out a cave in the trunk of the living tree. Though the fire caves on some of the redwoods look fresh, the last forest fire that occurred in Muir Woods was about 160 years ago.