Become a member and get exclusive access to articles, contests and more!
Start Your Free Trial

This is the 1st of your 3 free articles.

Become a member for unlimited website access and more.

FREE TRIAL Available!

Learn More

Already a member? Sign in to continue reading

Capital of Silicon Valley adopts bird-friendly building guidelines

San Jose, California. Photo courtesy of
San Jose, California. Photo courtesy of

We’ve learned that San José has become the fourth, and largest, city in California to enact bird-friendly building guidelines based on strategies published in 2011 by American Bird Conservancy (ABC).

ABC’s column “Eye on Conservation” appears in every issue of BirdWatching magazine.

Similar ordinances were adopted by San Francisco in 2011 and Oakland in 2013, while guidelines were adopted by Sunnyvale in 2014. San José, in the heart of Silicon Valley, is the third largest city in California.

“We are very excited that the city has taken action to reduce the risk of bird collision with glass windows and building facades,” says Shani Kleinhaus, environmental advocate for Santa Clara Valley Audubon Society. “It shows that nature and birds are an important part of the city’s sustainable future and are valued by San José’s residents, leadership, and city staff.”

Santa Clara Valley Audubon worked with the Loma Prieta chapter of the Sierra Club and the San José Environmental Services Department to craft and implement the bird-friendly guidelines, which will be applied citywide on a voluntary basis.


The department has developed a fact sheet and checklist that provide information on bird-safe design and outline voluntary bird-safe building measures. They include the following steps:

  • Reducing large areas of transparent or reflective glass
  • Avoiding transparent glass skyways, walkways, and entryways, as well as free-standing glass walls and transparent building corners
  • Avoiding the funneling of open space toward a building façade
  • Landscaping to reduce reflections and views of foliage through glass
  • Reducing or eliminating up-lighting and spotlights on buildings
  • Turning off non-emergency lighting at night, especially during migration (February-May and August-November)

“Without question, bird collisions are one of the most significant causes of bird mortality worldwide,” says Christine Sheppard, manager of ABC’s bird-collisions campaign and the author of its design guidelines. “It’s a problem that is probably escalating every year.”

Download ABC’s Bird-Friendly Building Design guidebook (PDF).

american-bird-conservancy-logo--140x84Birds collide with glass because they cannot see it as an obstacle. Rather, they fly toward reflections of trees and sky, or attempt to fly through apparent passageways. Collisions with glass are now implicated in the decline of many migratory species in the United States.


“Parts of this problem are very simple to understand,” says Sheppard. “For example, cues like window frames and even dirt tell people where to expect glass. Birds don’t learn these cues, and so they take reflections literally or try to fly through transparent glass to reach something beyond it.”

Between 365 and 988 million birds are killed annually in building collisions in the United States, say researchers Scott R. Loss, Sara S. Loss, and Peter P. Marra of the Smithsonian Migratory Bird Center and Tom Will of U.S. Fish and Wildlife Service’s Division of Migratory Birds.

In February 2014, the scientists published a systematic review of published studies and unpublished collision-monitoring datasets, concluding “that building collision mortality is one of the top sources of direct anthropogenic mortality of birds in the U.S.”


“Among other national estimates that are data-driven and systematically derived, only predation by free-ranging domestic cats is estimated to cause a greater amount of mortality,” they wrote.

Read more about the 2014 building-collision study.

Some species seem disproportionately vulnerable to collision with buildings. In San José, vulnerable species include Anna’s Hummingbird, Cedar Waxwing, Yellow-rumped Warbler, Lesser Goldfinch, Hermit Thrush, Varied Thrush, American Robin, and Cooper’s Hawk.

Simple steps that homeowners can take to reduce bird-window collisions is the topic of a popular talk that BirdWatching Editor Chuck Hagner delivers at festivals, meetings, and other events, most recently at the 2015 Space Coast Birding and Wildlife Festival in Titusville, Florida.


Read about 15 products that prevent bird-window collisions.

Read “Eye on Conservation” from American Bird Conservancy.

Learn about Santa Clara Valley Audubon Society.

Go to the Sierra Club Loma Prieta Chapter.


Originally Published

Read our newsletter!

Sign up for our free e-newsletter to receive news, photos of birds, attracting and ID tips, and more delivered to your inbox.

Sign Up for Free