Canaries were used in early coal mines to detect deadly gases, such as methane and carbon monoxide. If the bird was happy and singing, the miners were safe. If the bird died, the air was not safe, and the miners left. The bird served as an early warning system.
Domestic migration trends play a similar early warning system for states. California’s dynamism was always reflected by its ability to attract newcomers to the state. But today California’s canary is dead. read more »