Vocal Ontogenesis in Non-Passerine Birds

Vocal ontogenesis in non-passerine birds has been studied only in a few species from different orders. Call development takes place in them in two different ways. In the first case, call frequency is gradually decreased along with chick growth (e.g., Anseriformes, Galliformes, Falconiformes, and Accipitriformes). In the second case, chicks produce high frequency calls for a long time regardless of body growth, and changes from juvenile to adult calls are jump-like (Gruiformes, Charadriiformes, Columbiformes, and Coraciiformes). Such a sharp change from juvenile high-frequency vocalization to adult low-frequency vocalization is called voice-breaking. This type is described mostly in birds with prolonged parental care. In this paper, we review the studies dealing with call development in non-passerine birds. All species studied were grouped depending on the type of ontogenesis (from precocial to altricial), which made it possible to relate the type of ontogenesis to vocal ontogenesis. It turned out that the nature of vocal ontogenesis is not obviously related to the type of ontogenesis in the chicks.