Vocal repertoire of Azure-winged Magpies (Cyanopica cyanus): A context-associated communication system

Signals within animals' vocal communication are considered functional referential and context-specific. Even in the absence of the context, receivers are expected to acquire the information of calls and respond specifically. Whereas the framework was supported by plenty of evidence, its exhaustivity in describing all animal vocal-isations has been questioned. Here, we investigated the vocal repertoire of a cooperatively breeding species, Azure-winged Magpie (Cyanopica cyanus), to present evidence for referential signals. The results showed that Azure-winged Magpies had a relatively large vocal repertoire, consisting of twelve distinct calls. These calls were associated with the context including movement, begging for food, contact, vigilance against predators, etc. However, even the predator-specific alarm calls would induce various responses of receivers. This implies that multiple pieces of information are involved in the vocalisation, which could be utilised by the receiver to select an appropriate response based on the surroundings. Our study gives a detailed description of the context and function of the vocal repertoire in Azure-winged Magpies, laying the foundation for further investigation on the developmental mechanisms of bird vocalisations. This study also suggests that the referential signals of animal vocalisations may not be limited to the context-specific responses of receivers and need to be discussed from a broader perspective.