Disentangling effects of noise from presence of anthropogenic infrastructure: Design and testing of system for large‐scale playback experiments

Abstract

Anthropogenic noise may be detrimental to many bird species, and manipulative experiments would help us understand these effects. We present the design and validation of a self-sustaining solarpowered broadcasting system that will allow researchers to disentangle acute or chronic effects of noise from effects of the presence of infrastructure, even in remote areas. We tested the broadcasting system using a case study on noise from oil well infrastructure in southern Alberta, Canada. Recordings from 2 types of oil wells were obtained and then broadcasted through 6 independent playback units continuously for a period of 3 months in 2013, at sites undisturbed by oil development. Sound measurements at real oil wells and at sites with broadcasting systems simulating the noise from these oil wells demonstrated that real and projected noise had very similar sound pressure levels, attenuation trends, and spectral composition. Throughout this long-term playback experiment, the system produced power and noise reliably and consistently. In conjunction with bird surveys, this experimental design and infrastructure can be used to allow researchers to dissociate the presence of anthropogenic development from associated noise, providing us with information that will help decrease the environmental impacts of human activities. Ó 2015 The Wildlife Society.

Noise Source and Individual Physiology Mediate Effectiveness of Bird Songs Adjusted to Anthropogenic Noise

“…We recorded the playback song stimuli as spontaneous songs May – July 2014 at control and noisy [receiving high-fidelity playback 56 of oil well drilling noise 57 sites using Zoom H4N Digital Recorders with built-in stereo microphones angled at 90° at maximal recording volume in uncompressed audio (WAV fles at 48 kHz sampling rate, 16-bit resolution). All recordings were made in the same region as the experiment to ensure that regional variation could not impact comparison of adjusted vs. unadjusted songs, but recordings were spatially and temporally segregated from song playback sites to ensure that receivers never heard recordings of familiar individuals.…”

“…Infrastructure-free control sites, where unadjusted songs were recorded, contained only naturally occurring background noise, such as avian vocalisations and wind. Noisy sites, where adjusted songs were recorded, contained high-fidelity 56 , high-amplitude [88 dB(C) at 10 m (C-weighted time average sound pressure level for broadband sound; LC eq ] broadcasts of oil well drilling 57 . The drilling produces frequencies that are significantly different from screw pumps and pumpjacks, but intermediate to both, in the sparrow song range (Fig.…”

Trends and knowledge gaps in field research investigating effects of anthropogenic noise

“…However, replicating the spectral composition and sound pressure‐level attenuation of loud, low‐frequency, anthropogenic noise via playback of recordings is fairly involved (Rosa et al. 2015) and especially challenging at large scales and over long periods (Blickley et al. 2012).…”

“…Neither birds nor terrestrial environments limit the capacity for experimental study. However, replicating the spectral composition and sound pressure-level attenuation of loud, low-frequency, anthropogenic noise via playback of recordings is fairly involved (Rosa et al 2015) and especially challenging at large scales and over long periods (Blickley et al 2012). Therefore, researchers may have used actual urban and traffic noise to avoid methodological complications and ensure stimulus validity, at the expense of being able to demonstrate causation.…”

Impacts of oil well drilling and operating noise on abundance and productivity of grassland songbirds

“…We monitored bird abundance and nests in twenty-nine 64.7ha (i.e. quarter section) mixed-grass prairie sites during three We made recordings of three generator-powered pumpjacks, three power-grid pumpjacks (Rosa et al, 2015) and three different drilling rigs (Appendix S1). Active oil wells and drilling rigs were recorded at three different locations for a minimum of 65 min, in winds <7 km/hr, using Zoom H4N handheld recorders.…”