In the genus "Pica", the species is closest to the North American yellow-billed magpie ("P. nuttalli"). Both species share a common ancestor that migrated from Kamtchatka to Alaska some time in the Pleistocene. Black-billed and yellow-billed magpie diverged as a result of the glaciation of the Rocky Mountains. The yellow-billed magpie became isolated in the warm climate of California and adapted to it. The species' population is stable and it is currently not considered as endangered.