Temporal soundscape dynamics in a Magellanic penguin colony in Tierra del Fuego

Abstract

On Isla Martillo in Tierra del Fuego, we continuously recorded in a colony of Magellanic penguins (Spheniscus magellanicus) in the beginning of the 2016 molting season. Here we describe the daily soundscape dynamics within this colony using existing soundscape metrics, which were originally developed to facilitate acoustic-based ecological inferences from multi-source soundscapes. While these indices have exhibited great successes, little research has explored the utility of soundscape metrics for characterizing ecological patterns and processes when a single soniferous species dominates the soundscape. Bioacoustics offers tools for such applications, but soundscape metrics may be favorable in situations where sounds of chorusing animals temporally overlap or when sounds are non-stereotypical. Some of the diel behavior patterns of this species have been previously documented by studies focusing on foraging behavior, but these studies relied on human observation and dive trackers mounted on individual birds. Instead, we consider the potential utility of terrestrial acoustic recording to monitor populations and behavior of this near-threatened species. We interpret our acoustic data in the context of known Magellanic penguin behavior and the few non-penguin sounds in this habitat, and through this interpretation we evaluate how soundscape metrics can be used to assess nearly monospecific assemblages.