Nesting season prep at the Bison Paddock

For the fifth consecutive year, Golden Gate Bird Alliance is partnering with the San Francisco Recreation and Park Department to create nesting opportunities for White-crowned Sparrows, Tree Swallows, Western Bluebirds, and other species at the Bison Paddock in Golden Gate Park.

GGBA volunteers work with park department staff once a month to create habitat and maintain nest boxes at the edge of the paddock.

During their most recent work day in March, volunteers removed invasive weeds and planted native species that would attract White-crowned Sparrows to nest. They also relocated some Tree Swallow nest boxes in an effort to improve nesting success in the 2017 breeding season. During the fall, volunteers had cleaned out the boxes and documented contents such as eggs that did not hatch.

Removing invasive weeds at the Bison Paddock

“Because of our partnership with the Golden Gate Bird Alliance and our passionate volunteers, San Franciscans can enjoy watching birds and bison thrive in Golden Gate Park,” said Phil Ginsburg, SF Rec and Park General Manager. “We welcome the public to join us in our efforts to restore parks and natural areas, and encourage the return of wildlife in our City.”

The goal of the restoration project is to create habitat and nesting opportunities for White-Crowned Sparrows, a species that is diminishing in San Francisco. The Nuttall’s subspecies of White-Crowned Sparrows live along the California coast year round, while other subspecies spend only the winter here. White-Crowned Sparrows nest in a clump of vegetation on the ground or at the base of a bush or short tree. The nests are made of grass, leaves, twigs, pine, moss, bark, hair and feathers. The sparrows lay between two and five eggs in each clutch. By contrast, Western Bluebirds and Tree Swallows prefer to nest in the elevated boxes installed by GGBA and Rec & Parks.

Installing nest boxes for the 2017 nesting season at the Bison Paddock / Photo by Eileen Richey
Nest boxes for Tree Swallows and Western Bluebirds / Photo by Eileen Richey

“We’ve been delighted to work with Rec & Parks to enhance the habitat by the paddock for wildlife and people,” said Cindy Margulis, Executive Director of Golden Gate Bird Alliance. “Our members have cherished this remarkable park since our founding a century ago.  Restoration is one of the ways we can sustain the marvels of nature in urban parklands.”

“It’s so rewarding to work with volunteers to restore wildlife habitat and witness the fruits of our labor – it’s also nice to get outside and improve the parks that we love,” said Kimberly Kiefer, Director of Volunteer Services at SF Rec and Park.

GGBA nest box monitor Eileen Richey and SF Park & Rec staffer Ken Preston confer over placement of nest boxes
White-crowned Sparrow singing / Photo by Eddie Bartley

Golden Gate Bird Alliance member Susan Mullaney has volunteered at the Bison Paddock for over three years. Her work typically involves weeding along the edge of the path in the dry months of summer. In the winter, she plants native seedlings that provides food and shelter for birds, butterflies, and other wildlife. She also helps clean out the nest boxes each fall, after breeding season is over. T Mullaney said she has seen an increase in bird activity at the paddock over her three years working there.

“I see and hear more birds,” said Susan Mullaney. “It’s a little denser with vegetation, and the vegetation is more well-established. We’ve had American Goldfinches, White-crowned and Golden-crowned Sparrows, Tree Swallows, and juncos. And all summer the area is filled with hummingbirds.”


Want to help? Our Bison Paddock volunteer work day is the third Saturday of each month, from 9 a.m. to noon. The next one is April 15, 2017. No experience needed, all ages welcome! Details on our Volunteer web page