Simple vocal repertoire. The most common call is a long, harsh peeer or pee-ah that descends in frequency (Skutch 1960, Hardy 1969). Their alarm call or contact call is a variation on the common call, and is described as a harsh, squeaky chaa or chay (Skutch 1960). For a representative audio recording with sonogram, see audio
Brown Jays also make a quiet "hiccup" noise described as puck or huck (Sutton and Gilbert 1942). The "hiccup" is a regular component of the bird's vocal repertoire and is created by the rapid inflation of a bare piece of throat skin called the furcular pouch that is directly connected to the interclavicular air sac (Sutton and Gilbert 1942). The "hiccup" call is often difficult to hear and analyze with sonograms. Juveniles give a soft hew note and produce similar vocalizations as adults but with higher pitch and softer tone (dos Anjos 2009).
Selander (1959) notes that birds in Campache, Mexico have markedly higher frequency calls than other birds from Mexico, which corresponds with their smaller body size.
Brown Jays are frequently the first bird heard in morning choruses (Morrison and Slack 1977). Calling generally begins half an hour before sunrise as part of "rallying" behavior to begin foraging (Morrison and Slack 1977).
Places of vocalizing
Birds often vocalize while traveling in flocks (dos Anjos 2009). Pairs vocalize frequently from nests during the nest building period (Lawton and Lawton 1985).
Social context and presumed function
Alarm calls are given to warn group of predators. While incubating, females often utter a hunger call, pee-ah, which signals the mate or helpers to bring food (Skutch 1960).