Vocal individuality as a potential long-term monitoring tool for Western Screech-owls, Megascops kennicottii

Abstract

Recent studies suggest that individually distinctive vocalizations found in many avian species can be used in population monitoring. In this study we assessed whether vocal identification of male Western Screech-owls ( Megascops kennicottii (Elliot, 1867)) was possible, and if it could be applied as a long-term monitoring tool. Recordings were collected between 2001 and 2003 from 28 territories on southern and central Vancouver Island. As a quantitative descriptor of the calls, a total of 17 variables were measured from each of 1125 calls. A discriminant function analysis resulted in 92.3% of calls being correctly classified to individual territories within one season and 87.3% of calls in a cross-validation of the model. Variables that showed the greatest discriminant ability included length of call, internote distance between first note and second note, and number of notes per call. Of the 14 territories that had owl calls recorded over 2 years, 4 appeared to be occupied by a different individual in the 2nd year, 7 had calls that were consistent between years, and 3 had calls that were ambiguously classified between years. Our results suggest that Western Screech-owl calls have enough individually recognizable characteristics to aid in the tracking of individuals both within and between years, allowing for long-term monitoring of individuals.