| Cracids use exceptionally large variety of sounds for their communication, involving differentiated structures and including both vocal and instrumental sounds. This makes the bioacoustics of the family an important tool for evaluation of relationships, behavioral studies and field work. However, such high diversity of sounds coupled with an extremely variable behavior in acoustic communication brings some difficulties for the field observer. Advertising with a loud chorus, chachalacas are detected in a much larger radius than the thinly whistled song of the Bare-faced curassow. The wing-drummings of Piping guans can be heard far into the forest but are produced almost exclusively before dawn. Outside the booming season curassows are usually silent, and depending upon the time of year, guans will fly silently or call furiously when disturbed. These examples suggest that unless the intensity of calling, time and season of calling are known, sounds cannot be used for cracid field work, especially censuses. Since we see acoustic detection as the potentially most effective way to monitor wild cracid populations, we would urge cracidologists to focus on gathering the aforementioned information. Invaluable data on acoustic behavior may be collected by direct observation, particularly if made regularly. A result of this Symposium could be to organize such a data bank. A variety of good recordings taken in the field as well as in aviaries are available (a working list will be circulated during the symposium), but it needs to be gathered, complemented, analyzed and circulated. This could be a reality with the cooperation of interested institutions and individuals in charge of the Arquivo Sonoro Neotropical. |
