This flamboyant corvid, formerly included with Eurasian Magpie (P. pica) of the Old World, is now split as a separate species based on differences in genetics, vocalizations and social behavior. However, physical differences are slight with North American birds averaging less white in the wing. Our birds are also slightly smaller, but longer-tailed. Canon PowerShot SX50 HS.
References:
Marzluff, J. & de Juana, E. (2017). Black-billed Magpie (Pica hudsonia). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/60756 on 13 July 2017).
Trost, Charles H.(1999).Black-billed Magpie (Pica hudsonia), The Birds of North America (P. G. Rodewald, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America: https://birdsna.org/Species-Account/bna/species/bkbmag