The role of the physics of the syrinx in controlling the melody of a suboscine song

A. AMADOR; F. GOLLER; G.B. MINDLIN

Vancouver, Canada.

Conferencia; International Congress of Neuroethology; 2007

The physical mechanisms involved in song production in birds has beenwidely studied in the oscine suborder. The respiration generates the songrhythm while the tension in the labia of the syrinx is used to explore the differentsound frequencies of the melody. It was reported that when the trachealsyringeal nerve is denervated the song losses most of the acoustic properties butthe temporal structure remain unchanged. By the other hand, the group of thesuboscines has been poorly studied. This group includes more than a hundredof species, many of them in Latin America.In this work we present the simultaneous measurement of sound and pressurein the air sacs of the Pitangus Sulphuratus, known as Great Kiskadee or Benteveo.We found that the fundamental frequency of the song follows in a linearfashion the shape of the air sacs pressure. We also found that tracheal syringealnerve cut did not produce important changes in the song, in particular, thefundamental frequency remains unchanged. The results of these experimentssuggest that the respiratory activity is completely driving the song, rhythm andmelody.We also present a mathematical model for the dynamics of the syrinx: a twomassmodel that assumes nonlinear restitution properties for the labia. Thisnonlinear property is so important that without it, is not possible to emulatethe data.