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

PLoS One. 2017 Jan 13;12(1):e0169041. doi: 10.1371/journal.pone.0169041. eCollection 2017.

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.

MeSH terms

  • Acoustics*
  • Animals
  • Behavior, Animal / physiology*
  • Birds
  • Pattern Recognition, Automated / methods*
  • Signal Processing, Computer-Assisted
  • Sound*
  • Vocalization, Animal*

Grants and funding

This work was funded by the Brazilian Science Council (CNPq), National Institute for Science and Technology in Wetlands (INAU/UFMT: www.inau.org.br, 2011–2016), “Science without Borders” Program (CsF: www.cienciasemfronteiras.gov.br/web/csf), Mato Grosso State Research Foundation (FAPEMAT/PRONEX, Edit 009/2009, Process 838265/2009), Brehm Foundation for International Bird Conservation, Germany, and the project OP “Competitiveness” BG161PO003-1.2.04-0044-C0001 financed by the Structural Funds of the European Union, and the project ISP1 financed by the Technical University of Varna, Bulgaria. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.