Automated Sound Recognition Provides Insights into the Behavioral Ecology of a Tropical Bird

Abstract

Computer-assisted species recognition facilitates the analysis of relevant biological information in continuous audio recordings. In the present study, we assess the suitability of this approach for determining distinct life-cycle phases of the Southern Lapwing Vanellus chilensis lampronotus based on adult vocal activity. For this purpose we use passive 14-min and 30-min soundscape recordings (n = 33 201) collected in 24/7 mode between November 2012 and October 2013 in Brazil’s Pantanal wetlands. Time-stamped detections of V. chilensis call events (n = 62 292) were obtained with a species-specific sound recognizer. We demonstrate that the breeding season fell in a three-month period from mid-May to early August 2013, between the end of the flood cycle and the height of the dry season. Several phases of the lapwing’s life history were identified with presumed error margins of a few days: pre-breeding, territory establishment and egg-laying, incubation, hatching, parental defense of chicks, and post-breeding. Diurnal time budgets confirm high acoustic activity levels during midday hours in June and July, indicative of adults defending young. By August, activity patterns had reverted to nonbreeding mode, with peaks around dawn and dusk and low call frequency during midday heat. We assess the current technological limitations of the V. chilensis recognizer through a comprehensive performance assessment and scrutinize the usefulness of automated acoustic recognizers in studies on the distribution pattern, ecology, life history, and conservation status of sound-producing animal species.

Recommendations for acoustic recognizer performance assessment with application to five common automated signal recognition programs

“…Two of those seven papers also reported receiver operating characteristic (ROC) metrics (Katz et al 2016, Ulloa et al 2016, which incorporate scores from 0 to 1 implicitly. Of the other five papers that did not report score threshold, four mentioned score but did not report threshold used , Bardeli et al 2010, Jahn et al 2017 and one did not mention score at all (Duan et al 2013).…”

Vocal behavior of the Undulated Tinamou (Crypturellus undulatus) over an annual cycle in the Brazilian Pantanal: New ecological information

“…For example, numerous studies in temperate areas have demonstrated that bird vocal activity has an important role in territory establishment and mate attraction, and seasonal changes in vocal activity can therefore be related to the breeding phenology of birds (Catchpole & Slater, ). Knowledge regarding daily and seasonal variation in vocal activity in tropical resident species is lower than that in species from temperate areas (Demko & Mennill, ; Jahn, Ganchev, Marques, & Schuchmann, ), but studies addressing the vocal activity of tropical species are of interest since such activity is usually not restricted to the breeding period (Jahn et al, ; Odom et al, ; Topp & Mennill, ). Acquired knowledge about bird vocal activity can also be useful to plan surveys and develop effective monitoring protocols for bird species (Pérez‐Granados, Bota, Giralt, & Traba, ).…”

A spatiotemporal analysis of acoustic interactions between great reed warblers (Acrocephalus arundinaceus) using microphone arrays and robot audition software HARK

“…In this study, we manually identified songs of neighboring individuals (i.e., RYB, OTH, and UNK) using both automatic localization results and human observation. Automated sound recognition is a recent development in bioacoustics and bird monitoring (Jahn, Ganchev, Marques, & Schuchmann, 2017) and a benchmark problem in machine learning (Goëau, H., Vellinga, Planqué, & Joly, 2016). We expect that song classification based on localized and separated sound sources (Kojima, Sugiyama, Suzuki, Nakadai, & Taylor, 2016) will contribute to track the behaviors of conspecific individuals in our system.…”