This short review presents the results obtained in several localities of Brazil on the composition of forest bird communities. Data were collected since the late 80's, after we introduced a new methodology of quantitative survey, based on acoustic identification and unlimited-radius point census. Although these data are still scattered, they show uniquely precise and coherently comparative patterns of composition of forest bird communities. Our methodology has the advantage of being absolutely non-disturbing, highly efficient in the field and immediately processed. Results confirm that the structure of a bird community is a good indicator of biodiversity, particularly useful where biodiversity is high. Many of these data are available only in unpublished dissertations and abstracts of congress communications, or are being analysed. A cooperative program is needed to promote new surveys and publish their results, as a contribution for measuring and monitoring biodiversity, especially in complex endangered habitats.

The vocal repertoire of the Azure Jay Cyanocorax caeruleus (Vieillot, 1818) is approached from a quali-quantitative point of view. The qualitative analysis was carried out both in the field and in captivity: the quantitative analysis was made only in captivity. Social acoustic communication in the Azure Jay is achieved through the use of two types of call: basic and intermediate calls. Fourteen basic calls are identified and presented through sonograms: the sotto voce song (courtship call) is related only to courtship and the social call is interpreted as the song in the Azure Jay. The intermediate calls are recombinations of the basic calls uttered during an alteration in motivation level. Examples of them are presented through sonograms of vocalizations recorded during mobbing predators and intraspecific agonistic contexts. The social, social-alarm, contact, flight, proximity, threat and social identity calls were those most frequently uttered by daylight: the other calls represented around 15% of the total number of utterances. The hypothesis of the evolution in American Jays, which tends to simplification of vocal repertoire (HARDY, 1961; 1969), is analysed; C. caeruleus seems to have a small actively-used repertoire.

The physical parameters of vocalizations in Hyla rubicundula are analyzed in the topotypical population and some requirements for this kind of analysis are discussed.