Variação diária e espectral da atividade vocal de três espécies da família Tinamidae em florestas de terra firme da Amazônia brasileira

Abstract

Birds are known to share information through conspicuous acoustic signals. Acoustic signals are especially important in habitats where vegetation makes long range visual signals ineffective. However, species that share similar characteristics of acoustic signals might also experience acoustic interference. Species that are closely related phylogenetically can also overlap in ecological and behavioral characteristics, enhancing the chance of acoustic interference. In order to avoid acoustic signal overlap, there might be present behavioral adaptations such as adjusting their vocal activity to avoid syntopic congeners. In this study, we used autonomous recording units (ARUs) to sample the dawn chorus activity of three species of tinamous (Family Tinamidae) during the dry season for two consecutive years at the Biological Dynamics of Forest Fragments Project in central Amazon, Brazil. We applied a method that accounts for imperfect detection in order to estimate the time of peak vocal activity for each species, while considering effects from the sampling bias. This study investigates how the species Tinamus major, Crypturellus variegatus and C. brevirostris utilize the acoustic space in time, and evaluate the degree of overlap in spectral and temporal traits of their calls. Our results suggests that these species use the acoustic space in a similarly, broadly overlapping in relation to the timing of vocal activity. However, these species differ significantly in characteristics of their calls. Our sampling and analytical methods had a temporal and spatial resolution that few bioacoustics studies have utilized; therefore we reinforce the body of publications which make use of ARUs and the usage of detection probabilities to better understand the dynamics of the dawn chorus.