The Surprising Biodiversity in Golden Gate Park

I thought I’d hiked every trail in Golden Gate Park in over two decades exploring the park. But on a sunny morning in May, I headed up a hillside on a small, steep trail I’d somehow missed. At the top, I looked down over the park’s outdoor roller-skating rink and JFK Promenade. And then I looked down at my shoes.

My feet were sinking into a deep patch of sand. It was a reminder that if you were to pull up the carpet of green that covers most of Golden Gate Park, you’d find what was once named the “Great Sand Bank”— a thousand acres of sizable sand dunes made from when eroded granite washed down from the Sierra Nevada over the millennia and sculpted by the fierce winds coming off the Pacific. These dunes were then stabilized, shaped, and planted to become the contours and canvas of the park you see today.

It’s easy to forget that Golden Gate Park is a largely artificial landscape, as its lushness and large trees lure you into feeling immersed in nature, just as the park’s creators intended.

But while the native coastal dune, coastal dune scrub, and coastal grassland habitats are gone, there is no shortage of biodiversity in Golden Gate Park. You’ll find hundreds of species of birds, more than a dozen species of butterflies, and increasing numbers of native plants. There’s also a biodiversity hot spot that is one of the least visited parts of the park.

So the next time you visit Golden Gate Park, let biodiversity be your guide.

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The coast live oak woodlands

Coast live oak woodlands are the most biodiverse terrestrial habitat in California, home to hundreds of vertebrate species and thousands of insect and plant species. Before San Francisco was developed, coast live oak woodlands were scattered across the landscape. The acorns were central to the diet of the Ramaytush Ohlone people living on the San Francisco peninsula. 

The 50-acre coast live oak woodland in the northeastern corner of Golden Gate Park is the most significant remnant of this native habitat in the city and a worthy destination in itself. The woodland is designated as old-growth by the Old-Growth Forest Network. This thriving woodland established itself long ago in an island of chert substrate amid the dunes. While some oaks were logged after the great earthquake in 1906, when 40,000 people temporarily lived in the park, you wouldn’t know it given the size and density of most of the trees. 

Thanks to the work of volunteers, the understory is now a mix of native woodland and coastal scrub plants. This includes the San Francisco wallflower, found only along the coast from Sonoma to Santa Cruz counties.

Thankfully, the park’s original designer and first superintendent, William Hammond Hall, decided to preserve this oak woodland and other pockets of coast live oaks around the park. The trees didn’t have the look that the public wanted at the time, but Hall believed keeping them in and adding other types of trees nearby could help the coast live oaks become a “class of scenery desirable at these points.”

Beyond scenery, the oaks provide vital habitat, which is immediately apparent. Under the lace lichen that hangs from the oaks’ branches, brown creepers, nuthatches, and downy woodpeckers forage for bugs along the trunks, while acorn woodpeckers drill holes to stash acorns. 

Other noteworthy oak woodlands can be found near the Stanyan Street entrance, above Lily Pond, and past the western end of the AIDS Memorial Grove. The California Native Garden within the park’s San Francisco Botanical Garden includes a small oak woodland, too.

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A haven for birds

Golden Gate Park is an oasis for migrating birds on the Pacific Flyway, providing a resting place, fresh water, and food on long journeys. Very unusual birds occasionally make appearances, such as the yellow-green vireo, native to Central America, and the rustic bunting, which is native to Asia. (Check SFBirds.net for recent sightings.)  

Over the years, more than 200 species of migratory and resident birds have been recorded in the park, making for excellent birding. The Botanical Garden is probably the birdiest area thanks to the abundance of different flowers, plants, and trees. The Golden Gate Bird Alliance offers birding walks on the first Sunday of the month at the Botanical Garden and welcomes all levels of birders.

North Lake, Middle Lake, and Blue Heron Lake are excellent for birding, too. Blue Heron Lake was renamed in 2024 for the resident species that court, nest, and raise chicks in the tall Monterey pines from January through June. 

Bird biodiversity in the park is on the rise for the best reason: many more native plants. When Middle Lake underwent a major overhaul in 2024, more than 50 species of native flowering shrubs, perennials, ferns, and aquatic plants were added to support birds, insects, reptiles, and amphibians, including the threatened California red-legged frog. It’s already paying off, with nearly 80 bird species documented at Middle Lake so far this year.

There’s also good news for Nuttall’s white-crowned sparrows, which were once common in San Francisco. Since 2012, volunteers with the Golden Gate Bird Alliance have been planting and maintaining native dune plants, including sticky monkey-flower, California bee plant, coast buckwheat, and yellow bush lupine, next to the Bison Paddock. This means the sparrows now have everything they need in one place: open fields to forage in, plus tall grass that they can use to make nests in the shrubs.

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Bountiful butterflies

In the depths of “June gloom,” “no-sky July,” and “Fog-ust” in San Francisco, I wonder about the butterflies. As I learned from Liam O’Brien’s book Butterflies of the Bay Area and (Slightly) Beyond, butterflies not only need sunshine and flowers, they “seem to abhor the wind.” And, oh my, can Golden Gate Park be windy in the summer!

But butterflies are here, with about a dozen species present from late spring to early fall. The most common are American and West Coast ladies, anise swallowtails, red admirals, common checkered-skippers, and monarchs. These winged beauties are a positive indicator of the habitat the park provides, and you’ll find at least a few species any time of year.

Many butterflies look for hills where they can find one another in a mate-seeking behavior called “hilltopping.” The park’s highest peak, Strawberry Hill in Blue Heron Lake, is a favorite for butterflies and a great place to see them. 

Volunteers have been pulling invasives and adding natives on Strawberry Hill since 2010, including planting the California Dutchman’s pipe, which is the host plant for the stunning California pipevine swallowtail. You’re most likely to see the butterflies between March and June. For more guaranteed sightings, head to the garden of California Native Plants in the San Francisco Botanical Garden. And according to O’Brien’s book, you can find fiery skippers at the Great Meadow at the Botanical Garden.

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