 Tyranni

Tyranni, the suboscines, is a major branch of Passeriformes distinct from Acanthisittidae and from the songbirds of Passeri. It includes the eastern phoebe. The taxonomic distinction makes comparisons of vocal development especially informative: a pattern established in an oscine songbird need not apply to every passerine.^[ref]

A 1991 experiment tested whether the eastern phoebe required hearing its own voice to develop normal song. Four birds were collected as nestlings and hand-reared; before they began singing, they were deafened. Their later songs were compared with those of intact laboratory birds and wild males and were judged normal. In these tested birds, normal song development therefore did not require auditory feedback.^[ref]

The experiment separates a developmental requirement from a correlation: hearing song and producing song normally occur together, but removing feedback tests whether it is necessary. The result concerns the tested species and conditions. It should not be generalized into a claim that no member of Tyranni can ever modify a vocalization through learning.