Dynamics of communal vocalizations in a social songbird, the zebra finch (Taeniopygia guttata).

Colonies or communities of animals such as fishes, frogs, seabirds, or marine mammals can be noisy. Although vocal communication between clearly identified sender(s) and receiver(s) has been well studied, the properties of the noisy sound that results from the acoustic network of a colony of gregarious animals have received less attention. The resulting sound could nonetheless convey some information about the emitting group. Using custom-written software for automatic detection of vocalizations occurring over many hours of recordings, this study reports acoustic features of communal vocal activities in a gregarious species, the zebra finch (Taeniopygia guttata). By biasing the sex ratio and using two different housing conditions (individual versus communal housing), six groups of zebra finches were generated, with six different social structures that varied both in terms of sex-composition and proportion of paired individuals. The results showed that the rate of emission and the acoustic dynamic both depended on the social structure. In particular, the vocal activity of a group of zebra finches depended mainly on the number of unpaired birds, i.e., individuals not part of a stably bonded pair.