VOCALIZATIONS OF THE BLUE-FRONTED AMAZON (AMAZONA-AESTIVA) IN THE CHANCANI RESERVE, CORDOBA, ARGENTINA

The calls of the Blue-fronted Amazon (Amazona aestiva) are described a nd their possible function within the social organization of the speci es during breeding and non-breeding seasons are discussed. We identifi ed 9 vocalizations; six (''wak-wak'', ''wa-wawawa'', transitions, ''gu -gugu'', guturals, ''ka-kaka'') were nonspecific and were given in sev eral circumstances: alarm, contact, feeding, and flying. The remaining had specific contexts: ''waahh'' (agonistic), ''grr-uip'' (contact in flight), and songs (reproduction-territorial). Vocalization rates inc reased in alarm contexts and during the non-breeding season, probably as a result of increasing interactions between individuals. The freque ncy containing the greatest amount of energy was a useful variable to characterize Blue-fronted Amazon calls, particularly at the species le vel. The most commonly used vocalization, ''wak-wak'', has structural features that promote directionality and short-range transmission, enh ancing its usefulness for the aggregation of individuals. It is sugges ted that songs were derived from a process of repetition and increasin g variability from gutural calls. The highly contextual variability of these calls may be due to an incompletely specialized repertoire or a vocal system based upon combinations of calls for conveying messages.