 Adam Tierney and colleagues argued in a 2011 paper that the similar motor constraints on human and avian song drive these to have similar song structures, including "arch-shaped and descending melodic contours in musical phrases", long notes at the ends of phrases, and typically small differences in pitch between adjacent notes.They excluded birds like the European starling which use many buzzing or clicking noises that are inharmonic, working instead with birds with a strong pitch structure like the field sparrow "Spizella pusilla" (Emberizidae), the Eurasian treecreeper "Certhia familiaris" (Certhiidae) and the summer tanager, "Piranga rubra" (Thraupidae).Hollis Taylor argued in her 2017 book that the vocalizations of the pied butcherbird are music, rebutting musicological objections to this in detail.