The Peripheral Hearing Organ of Birds

Abstract

Compared to the reptiles, birds are, in general, highly vocal animals. Although there is thus no problem in delimiting an obvious function for the hearing system, it is somewhat enigmatic that this vocality is not accompanied by large anatomical differences in the inner ear compared to that of the much less vocal Crocodilia, the most closely related group of reptiles. In the past, there have been divergent views on the function of the avian hearing organ. Because the anatomical features were so different to those of mammals, most authors took a cautious approach, assuming that apart from some basic aspects, the function of the bird and mammal cochleae would show substantial differences. In recent years, there has been an increasing interest in the function of the inner ear of birds, especially since some new findings indicate that there may indeed be important functional parallels to the inner ear of mammals. In general, the hearing of birds has received more attention than that of reptiles, so that it has been necessary in this chapter to be more selective in the presentation of data and discussion. For more anatomical detail, the reader is referred to other reviews (Baird, 1974; Lewis et al., 1985; Pumphrey, 1961; Saito, 1980; Schwartzkopff and Winter, 1960; Smith, 1985)