Guttural calls of Blue-fronted Amazons: Structure, context, and their possible role in short range communication

Structural variability of guttural calls of Blue-fronted Amazons (Amazona a estiva) was examined and the contexts in which they were given discussed re lative to the role these vocalizations might play in short-range communicat ion. Recordings were obtained at the Chancani Reserve, Cordoba, Argentina, during breeding and non-breeding seasons. Guttural calls were given year ro und, but were more common during the non-breeding season when most of the i ndividuals were interacting in flocks. Gutturals were detected when perched parrots contacted each Ether, during take-offs, landings, complex flock fl ying maneuvers, and feeding sessions. Guttural calls were subdivided into f our types based on structure, but none of these types could be clearly assi gned to a specific context. Structural variation in guttural calls was cont inuous rather than discrete, with the variability within and among individu als being similar. Many guttural notes graded into one another and were com bined with other vocalizations. Gutturals were brief, had sudden onset, wid e bandwidth, and low intensity. Gutturals could be regarded as short-range calls because of their large structural variability (fewer restrictions of sound attenuation and degradation) and low intensity (decreased attraction of predators). They were also produced by large flocks, probably as a means of maintaining contact, enhancing group spacing, and coordinating movement s of individuals.