Feb 3, 2015 · 1 minute

Bringing a canary into a coal mine doesn't do much good if no one pays attention to the bird. Miners brought them into mine shafts to have an early detection system for carbon monoxide poisoning -- it would die before the miners even felt sick, indicating a potential problem. If no one noticed the bird had stopped chirping, however, its death would have been meaningless.

Companies have adopted a similar practice involving deleted statements, legal documents, and secret government requests. It allows them to disclose classified requests by removing a claim, such as "we've never received a secret government request," from transparency reports when it stops being true. These "warrant canaries," like their namesake, send warnings through silence.

But what if nobody's listening for these warrant canaries to stop their chirping? Ignoring them is like miners tuning out their canaries: it defeats the entire purpose of the exercise and makes everyone vulnerable, whether it's to carbon monoxide poisoning or to classified data requests.

A new group intends to listen for that dangerous silence. The group's called Canary Watch, and it was formed by Harvard's Berkman Center for Internet & Society, the Calyx Institute, New York University's Technology Law and Policy Clinic, and the Electronic Frontier Foundation to monitor some of the warrant canaries included in technology companies' transparency reports.

Besides listening to find out when a warrant canary goes silent, Canary Watch also hopes to explain what the editing or removal of a warrant canary actually means. It can be difficult to interpret what a company is trying to "say" when it removes a warrant canary from a document -- deleting a vague statement about secret government requests doesn't allow a lot of nuance.

Yet these warrant canaries are the only ways for companies to reveal classified data requests to their users. The government has made it increasingly difficult for tech companies to talk about surveillance efforts -- hence the limited utility of "transparency reports" and little information about how companies fight these requests -- making silence the best disclosure tool available.

So long as someone's paying attention to that silence, of course. Otherwise these companies are flouting government efforts to keep data requests secret with imaginary canaries for nothing.

[Illustration by Brad Jonas for Pando]