Both males and females sing a soft medley of sweet notes that can last up to 5 minutes. Scrub-jays typically do this only during courtship and when the pair is close together.
California Scrub-Jays, like other jays, are extremely vocal. Behaviorists have described more than 20 separate types of calls for this and the closely related Woodhouse's Scrub-Jay. Examples include a weep uttered during flight, while carrying nesting material, or while taking cover from a flying predator; a bell-like shlenk used antagonistically, a quiet kuk exchanged between mates, and loud, rasping scolds for mobbing predators.
Scrub-jays often clack their bill mandibles together to make a sharp rapping. Their wings make a whooshing sound on takeoff, and they exaggerated this during altercations.