Influência do ruído ambiente em canções de um pássaro Oscine e um Suboscine da mesma população

Abstract

Anthropogenic noise may affect acoustic communication of species through masking, with potential fitness consequences. Several species from different groups then show differences in call features or behavior between noisier and quieter regions, allowing them to survive and reproduce in the noisy places. Differences may arise through short (call plasticity), medium (ontogenetic) or long-term (evolutionary) mechanisms. For the short and medium term mechanisms, intrinsic characteristics of the species may interfere with the modification of the signals, particularly the way that vocal learning occurs. Within the Passeriform order, the oscines show vocal learning, while the suboscines do not. Here we report a study comparing song characteristics of an oscine (southern house wren Troglodytes musculus) and a suboscine bird (great kiskadee Pitangus sulphuratus) of a single population at two different places of their habitat showing different noise levels. We predicted that the oscine bird would show differences in the calls between the regions, while the suboscine species would not show them, given the differences in song learning and plasticity between those groups. Contrary to our predictions, almost none of the song parameters of both the great kiskadee and the southern house wren differed between those areas. The results point to the possibility that there might not be short term acoustic adaptation in bird song features in these species (or that there might not be a difference between oscines and suboscines or learners vs. non-learners), but several alternative hypotheses exist.