Plumage and behavior differ greatly between interior and coastal populations. Coastal populations of the western scrub-jays are confiding, tame, and easily seen. Interior populations are more secretive and often are seen darting from bush to bush or are simply heard giving their harsh calls. Pairs of all North American subspecies hold territories year-round. Polytypic. Length 11".

This is a long-tailed jay with a small bill and no crest. Adult: generally bluish above, gray below with a contrastingly paler throat and upper breast, and a variable bluish band on the chest. Juvenile: much grayer overall, showing very little blue on the head. Flight: Usually undulating with quick deep wingbeats.

The subspecies of western scrub-jays form 3 well-defined subspecies groups that may represent separate