 Adult birdsong is actively maintained by error correction by Samuel J. Sober and Michael S. Brainard

Nature Neuroscience12(7),927–931 (2009), DOI10.1038/nn.2336. Abstract and Fig.1: microphone, online pitch processing, headphone playback to adult Bengalese finches; compensation and return toward baseline. Primary full text pmc.ncbi.nlm.nih.gov/articles/PMC2701972/ .