With their large size, bold pied plumage, and fondness for open areas, black-billed magpies are easily seen. They hop and walk on the ground with a swaggering and confident gait. Monotypic.

Biologists already knew the corvid family–it includes crows, ravens, rooks, magpies and jackdaws–to be among the smartest of all birds. But this remarkable piece of behavior–it features in ...