White-throated magpie-jays are one of the most notably vocal species where they are found, and their vocal talents are incredible. As such, a list of vocalizations specific to white-throated magpie-jays is nearly impossible to produce. However, at least 14 functionally distinct classes of vocalizations have been described, and some of these are used much more frequently than others.
Mobbing calls are a harsh raah, raah, raah, or rah-rah-rah-rah-rah. These vary in both rate and call length depending on the nature of the threat; longer calls are given at higher rates in response to high-threat predators.
Aerial predator alarm similar to mobbing call (rahrahrah). When given all nearby magpie-jays will dive into heavy cover. This vocalization is usually produced when a raptor surprises a magpie-jay. Sometimes produced in response to low-flying Turkey Vultures (Cathartes aura).
Raptor alert calls variable, but generally soft, even, and somewhat higher-pitched. Magpie-jays give these rarely when they detect a high-flying raptor.
Soft alert calls consist of quiet notes produced when a low-threat object already discovered shifts positions or approaches a magpie-jay. Oop, up, ip, tuk, kuk, produced singly or in pairs.
Loud predator alert calls make up the bulk of the magpie-jay repertoire. They are given in low-threat alarm contexts or toward other species, usually by males. A wide range of sounds are produced in this context: more common variants in Costa Rica include: peeoo, kee-pow, pupupup-pow, prrreeeet, whoop. Such calls may be produced as the jay flies toward a car, human, dog, coyote, guan, or perched raptor. Males also produce such calls while patroling their home ranges, especially in the hour before dawn, occasionally in near-dark conditions (i.e. early dawn chorus).
Adult begging: both males and females may produce loud plaintive vocalizations that are identical to the begging of fledglings. Females in particular sit on nests before and during incubation and may beg at rates of over 10 calls/minute for several hours. Begging may increase in tempo as a group member approaches with food, and may culminate in a rapid series, terminated by a gargling moan as the female is fed.
Social chirring: Another commonly heard vocalization is produced when a female and her mate are coordinating a nesting attempt. These calls are probably given during pair formation as well. The two individuals (and occasionally other group members) move nervously near each other, producing a medium range chirr-chirr-chirr-chirr or tszerr-tszerr-tszerr-tszerr. Often given during nest-building.
Similar calls may be produced with less intensity when two group members or neighbors interact, and more intense variants are also given when two groups have a territorial border encounter.
White-throated magpie-jays produce a harsh squealing distress call when constricted. In the field this call was recorded occasionally during banding activities, but also when a group female was caught by the breeding female near the nest.
Like some other New World Jays, male magpie-jays will sing softly in three contexts: during courtship, when they fluff up their feathers, erect their crest and raise their tale and sidle along a branch; in dominance encounters, rarely, in a similar fashion; and occasionally toward apparent threats, such as humans, during which they usually do not dance but may hold their head high, tail down, and crest and neck feathers erect. Songs are not phrased like in many other passerines, but a near-continuous, barely audible warbling, which may include mimicry and sounds very unlike the rest of the repertoire.