Efficiency of the playback technique in the detection of Atlantic Forest owls

Owls are birds that are difficult to detect, since most of them are nocturnal, of forest habits and with low population densities. One commonly used method for studying and surveying owls is «playback.» The method consists in the reproduction of vocalizations of owls, waiting for the birds to respond to the calls. The objective of this study was to evaluate the efficiency of the playback technique in the detection of forest owls. Between the years of 2012 and 2016, nocturnal samplings were carried out in some forest remnants in the State of Paraná and São Paulo, Brazil, all within the Atlantic Forest biome. Two methods were used to detect owls: 1 – listening points, 2 – playback, both concentrated in the first 3 hours of the night. As a result, playback proved to be the most efficient method to detect the presence of owls in the sample areas, especially the species of the genus Strix, Aegolius and Pulsatrix. Compared to the listening point, the playback increased from 30% to 80% the success in detecting owls at the sampling points. Species such as Aegolius harrisii, Strix virgata and Strix huhula were only confirmed by this method. Based on these results, it is advisable to use playback as the main technique for surveying owls in forest areas.