A canary is a small songbird known for its beautiful, cheerful singing. Wild canaries are greenish-yellow, but pet canaries have been bred in brilliant shades of yellow, orange, and even white. People have kept canaries as pets for centuries, delighting in their melodious songs.

The phrase canary in a coal mine comes from a safety practice that began in the late 1800s. Coal miners would bring caged canaries deep underground because these sensitive birds would show signs of distress or stop singing if dangerous gases like carbon monoxide built up in the mine. The canary's reaction gave miners an early warning to evacuate before the invisible gases could harm them. Today, people use this phrase to describe any early warning sign of a larger problem: “The closing of three local stores was a canary in a coal mine for the town's economy.”