You know those sirens that terrify tourists and don't particularly faze locals every Tuesday at noon, blaring for 15 second to test our "Outdoor Public Warning System?"

Well, in a story sure to make your heart soar like a predatory bird, San Francisco has turned off one of our 114 air-raid-sounding alarm towers because a red-tailed hawk family is, or was, roosting there, and the Department of Emergency Management did't want to disturb their chicks.

The sonic blog Disquiet picked up the detail from Rick Prelinger, who along with Megan Prelinger founded the independent SoMa Prelinger Library in 2004. Prelinger noticed the nest at Taraval and Great Highway and discovered that the tower had already been disabled by the Department, who had previously observed the hawks.

It's possible, though, that the siren will start up again soon. "I think the chicks have fledged and nest was empty when I checked last week," Prelinger wrote on Twitter a few days ago.

In case you wanted to know where, exactly, all that noise comes from on Tuesday, there's a map for you to consult.


And if you're craving that sweet siren song from the Outdoor Public Warning System right now, here's a brief background video.

Last, if you're looking to get the alarm in the form of a tweet, that's also possible thanks to one local Twitter account that's so stupid, it's brilliant.

Related: Video: Telegraph Hill Coyote Chills With Coit Tower Tourists

Department of Emergency Management