Birds collected after colliding with buildings in Toronto 2009. (Kenneth Herdy/FLAP Canada)
Birds collected after colliding with buildings in Toronto 2009. (Kenneth Herdy/FLAP Canada)

Tourists aren’t the only out-of-towners that flock to the city by the bay. Each year, more than 250 species of birds stop in San Francisco during their fall and spring migrations, said Judith Pynn of the Golden Gate Audubon Society. But birds passing through the big city on the Pacific Flyway can be thrown off by unfamiliar terrain, particularly windows.

They either don’t see the glass, or see a reflection and try to fly through it. “They may mistake it for a habitat [or] may see their own reflection and think it’s a rival and try to attack,” said Pynn, a resident of the Outer Sunset in San Francisco. She said a bird flew into a window in her home a few months ago. Pynn suspects that the window’s reflection of a nearby tree may have lured the bird to its death. “It’s a real hazard,” she said.

Hundreds of species of birds fly through San Francisco on the Pacific Flyway migration corridor. (U.S. Fish and Wildlife Service)
Hundreds of species of migrant birds fly through San Francisco on the Pacific Flyway migration corridor. (US Fish and Wildlife Service)

According to the National Bird Conservatory, between 100 million and one billion birds die each year from colliding with glass windows of commercial or residential buildings.

In 2011, San Francisco passed the first standards in the country aimed at reducing the hazards of commercial buildings by requiring window film or lighting adjustments. Now, the San Francisco Planning Department is enlisting the help of volunteers like Pynn to measure the damage caused by residential windows.

Once a week during the fall, Pynn will walk around the perimeter of her home in search of dead or injured birds. If she finds anything, she’ll report it to the Planning Department.

“We’re hoping to get people excited and involved and be able to collect some really great data,” said Andrew Perry with the San Francisco Planning Department’s Bird-Safe Buildings Project. “Citizen science is a very powerful tool.” He added that participants don’t need to be hardcore birders. Residents can take pictures of birds and upload them to the web for someone else to identify.

The city already has anecdotal evidence of residential bird collisions, Perry said, but this project will be the most extensive study of residential collisions on the West Coast.

“The city sending a clear message that it takes bird-safe buildings seriously, and it’s not just about commercial property owners,” said Cindy Margulis, Executive Director of the Golden Gate Audubon Society. This study will better inform the city’s policymakers on the hazards of residential windows, she said. “We need more science.”

The citywide project will be ongoing, and participants are being asked to commit to monitoring for at least one migration period. Residents who live near parks are of particular interest to the study, as birds are more likely to be concentrated in those areas. This fall’s migration period began August 15 and runs through November.

Those interested in monitoring their own homes can email Andrew Perry with the San Francisco Planning Department:

San Francisco Wants to Know: Is Your Living Room Window Killing Migratory Birds? 22 August,2014Sally Schilling


Sally Schilling

KQED Science intern Sally Schilling brings environmental conflicts to life by finding the people most affected by them. She’s recently told the stories of park rangers on the hunt for redwood burl poachers, and the accidental activists in Pittsburg who are fighting a proposed crude oil facility being built in their backyards. Sally is currently studying video journalism and investigative reporting at the UC Berkeley Graduate School of Journalism. She grew up on an organic farm near Davis, Ca.

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