The Steller's' Jay is a common scavanger which lives west of the Rocky Mountains from Alaska to Mexico. It's most obvious difference from the common Blue Jay that lives in the rest of North America is its coloring. It commonly has extensive black on the head and upper body while the common Bluejay has a white head or perhaps more accurately a blue and white head.
The birds are very nervous and flee quickly, but will come in fairly close to people to get food. They usually are found in groups, but smaller than the flocks of crows often seen in the west. It is a relative of the Crow, and shows the opportunistic behavior patterns of the crow, but is smaller, and more aggressive.
Steller’s Jay (Cyanocitta stelleri) is one of two species in the genus Cyanocitta, the other species being the Blue Jay (Cyanocitta cristata). The Cyanocitta genus in turn belongs to the Corvidae family, which consists of the crows, ravens, rooks, jackdaws, jays, magpies, treepies, choughs, and nutcrackers, for a total of over 120 species. The closest relatives of the Corvidae are the shrikes (Laniidae), and Birds of Paradise (Paradisaeidae).
Additional information: see Wikpedia - Steller's_jay