An animated 3D model of the synchronous movements of the suprasyringeal structures and organs in the neck of a vocalizing songbird, the Northern Cardinal ( Cardinalis cardinalis ) (918.8)

In birds, sound is generated in the syrinx and is filtered by suprasyringeal structures that move relative to one another. The larynx moves relative to the hyoid apparatus, which moves relative to the mandible, which in turn moves relative to the skull. The cervical vertebral column moves the head relative to the thorax. The esophagus and trachea move relative to the vertebral column. The interplay of these elements was analyzed in a songbird, the Northern Cardinal, through an animated 3D model that was created from a CT scan based on prior anatomical analyses. The movements of the vocalizing behavior were modeled by matching the configuration of the 3D model to individual images of a 2D x‐ray video of a singing bird in lateral view. To estimate the degree of yaw and roll of the head, the x‐ray video was synchronized with a video recorded from above. To compensate for side‐to‐side movements of the bird, the images of the 2D x‐ray video were enlarged or reduced. A separately recorded x‐ray video in frontal view was used to verify the proper spatial configuration of the skeletal elements in the individual images of the animated 3D video. The video of the 3D model was synchronized with the audio recording to analyze the movements required to produce specific sounds. Grant Funding Source : Supported by NIH grant NINDS R01 NS029467 to RAS; LSU Foundation to DGH