Variation in birds' vocalization is related to several factors including the ability to learn. Parrots and oscines socially learn their vocalizations and in general show greater variation in this phenotype. Other groups such as suboscines are known to have no learn ability and generally have less vocal variation. Furthermore, ecological aspects influence the transmission of acoustic signals through the environment. Climatic conditions, vegetation composition and body size can influence the variation of vocal parameters in different ways. These environmental factors added to vocal learning can be related in different ways and intertwine the complexity of vocal evolution, causing groups to respond to selective pressures in different ways. Thus, we are investigate whether the social vocal learning of oscines and psittacines favors a greater variation in vocal parameters in a geographic space and to identify whether there would be a spatial structure of these parameters associated with learning (chapter 1); and to investigate whether ecological factors, such as environmental variables and body size, have more effect on vocal parameters of suboscines, in relation to vocal parameters of oscines and psittacines, due to vocal learning capability (chapter 2). In chapter 1, our results indicated that in the spectral components parrots and oscines showed greater geographic variation than suboscines. In relation to temporal parameters parrots showed greater variation in relation to oscines and suboscines, and the last two did not differ from each other. We did not find spatial structure of vocalizations associated with learning. In chapter 2, for temporal parameters we verified that only the body size had an effect on the vocal duration in the suboscines and the environmental variables had no effect on the duration and rhythm of their vocalizations. Regarding to spectral parameters body size had an effect on the peak frequency of psittacine and oscine vocalizations, and body size and mean temperature had an effect on the bandwidth of oscine vocalizations. No ecological factors had effect on the spectral parameters of the suboscines.