Playback experiments in avian vocalization: use and design

Acoustic playback is routinely used to study avian vocalization． Playback experiment investigates the function and biological significance of sound signals by playing natural or synthetic sound signals to birds, to observe their reactions, and to record behavioral variables of target individuals． A total of 440 publications on avian vocalization playback from 1993 to 2022 were retrieved from Web of Science． Playback experiment had been done in intraspecific research, e.g., sexual selection and dear-enemy effect, interspecific research, e.g., predation and brood parasitism, and multi-species research, e.g., mobbing behavior and community monitoring． Playback experiments are also used in taxonomy． The design of playback experiments often adopts one-speaker playback, including two implementation methods, i.e., one-speaker playback with or without replication． Multimodal signal stimulation also accounts for a certain proportion in playback experiments． However, the experimental designs of two-speaker playback and interactive playback are far less important than expected． Now, the problem of pseudo-replication in playback experiment has been well solved． The reproducibility of the playback experiment process, the lack of female bird playback in taxonomy research, storage format of playback sound needs to be paid attention to in future research．