Acoustic directionality of red-winged blackbird (Agelaius phoeniceus) song relates to amplitude and singing behaviours

摘要: Sound waves typically radiate from a vocalizing animal with unequal amplitude in different directions; this may profoundly affect communication, favouring adaptations that use or compensate for directionality. Previous studies suggest variation directionality among vocalization types is related to function, vocalizations such as alerts being relatively omnidirectional, thus maximizing the number of surrounding receivers, and courtship calls directional, reducing eavesdropping by beaming sounds at targeted receiver. Here we examine within type, bird songs, test hypotheses about how song relates singing behaviour social context singing. We measured red-winged blackbird songs field using calibrated microphones encircling bird. found types, possibly allowing males select their repertoires suit context. support hypothesis are related, more-directional delivered higher amplitudes. In addition, negatively degree male rotation on perch between vocalizations, suggesting combine omnidirectional broadcast face receiver produce directional during direct interactions. also observed note songs. These results plays an important role shaping structure blackbirds.