The Outdoor Public Warning Nest

San Francisco's Tuesday noon siren becomes a Red-Tailed Hawk shelter


Every Tuesday at noon in San Francisco, the outdoor public warning system rings out across the city. There are 109 speakers in total as part of the OPWS, though these days only 108 of them are functioning. That’s because the one at the intersection of Taraval and Great Highway has, reports Rick Prelinger, been turned off. The Taraval siren isn’t broken. None of the sirens are broken. The whole point of the weekly siren test is to check and quickly repair any siren — any one of the four speakers that make up each of the 109 sirens — that isn’t functioning. The Taraval siren is silent because it has become a shelter for a family of Red-Tailed Hawk.

Prelinger, who gave me permission to post the photo shown up top, wrote on his Facebook page:

When I toured the San Francisco Department of Emergency Management on June 16 prior to my communications infrastructure talk that evening at Long Now’s Interval, I was told they’d turned off the emergency siren and speakers at Taraval and Great Highway so as not to disturb a nesting Red-Tailed Hawk. Of course I had to go and see what was going on.

(Update: He also clarified this morning that the nest may be empty by now.)

If you’ve never heard it, here’s a recording:

Here’s a shot of the tower at Taraval and Great Highway via Google Street view. This is facing north. A very short walk to the left and you hit the Pacific Ocean:

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Residents near Taraval and Geary needn’t worry too much for their safety. There are three other sirens within blocks. For reference, Taraval and Geary is number 78 in this chart, available as a PDF at the San Francisco Department of Emergency Management’s website, The actual number of sirens is a little unclear. The main site states 109, but there are 114 listed in that PDF and 111 in an accompanying list. Note that some, like the one at Taraval and Great Highway, double for tsunami warnings.

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Thanks to Rick Prelinger — associate professor at the University of California, Santa Cruz, and founder of the Prelinger Archives ( — for sharing the photo, and to Paul Socolow for alerting me to it. More on the sirens at For additional reading, last month the duo 52-Blue (Nick Sowers and Bryan Finoki) in their series ran a piece on the tainted, wartime history of the siren. My audio recording of the siren is at And for a recent shot of siren number 102, the one closest to my office, visit

One thought on “The Outdoor Public Warning Nest

  1. I live in the neighborhood by the siren and can confirm that the birds flew the coop some time ago, mid-July-ish. I believe there were three babies. It was pretty fun seeing them learning to fly. Mama bird would sometimes flap like crazy and just hover over the nest for a bit. They were crazy noisy too, but it was pretty cool. They sounded just like the ‘generic hawk sound #3’ you hear in just about every western.

    Apparently one of the babies had some trouble when it was finally shoved out of the nest, but it was picked up by animal control. I posted a picture of the flyer that was posted around the neighborhood in reply to Prelinger’s tweet, taken on July 28, at which point all the birds had vacated.

    What I think is the papa bird had been lording over the neighborhood for the better part of a year before he mated, and you can still occasionally see him along Great Highway. It’s funny how if you see the same bird every day, you start to recognize it on sight, especially when it’s in a different neighborhood.

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