Noisy anthropogenic infrastructure interferes with alarm responses in Savannah sparrows ( Passerculus sandwichensis )

Abstract

Many birds rely on anti-predator communication to protect their nests; however, anthropogenic noise from industrial activities such as oil and gas development may disrupt acoustic communication. Here, we conducted acoustic playback experiments to determine whether Savannah sparrows (Passerculus sandwichensis) responded to conspecific alarm calls by delaying feeding visits, and whether this response was impaired by noise-producing natural gas compressor stations, generator- or grid-powered screw pump oil wells, and noise amplitude. We played alarm calls, and, as a control, western meadowlark songs, to Savannah sparrows as they approached their nests to feed their nestlings, and measured feeding latency. The greatest impacts on behaviour were detected at the noisiest treatment, compressor stations; feeding latency was shortened here compared with control sites, which may expose nests to greater predation risk. As noise amplitudes increased, Savannah sparrows took longer to feed following meadowlark playbacks, perhaps because noise interfered with interpretation of acoustic cues. The effects of compressor stations on anti-predator behaviour may be best explained by the distracting effects of anthropogenic noise, while increases in feeding latency following meadowlark playbacks may be explained by a heightened response threshold caused by acoustic masking. Industrial infrastructure can influence the reproductive success of wildlife through its impact on perception and interpretation of conspecific signals, but these effects are complex.

Why does noise reduce response to alarm calls? Experimental assessment of masking, distraction and greater vigilance in wild birds

“…Almost all birds fled to alarms when not mixed with noise, but response declined monotonically until there was no response when mixed with noise at or above 58 dB. This experiment demonstrates that background noise itself affected the response to alarm calls, because playbacks were matched by location, eliminating potential confounds such as location‐specific variation in predator density or effects of noisy infrastructure unrelated to noise itself (Antze & Koper, ; Grade & Sieving, ). Furthermore, birds did not flee to noise‐only playbacks, showing that fleeing was to alarm calls and not the accompanying noise.…”

Urban Noise Restricts Song Frequency Bandwidth and Syllable Diversity in Bananaquits: Increasing Audibility at the Expense of Signal Quality

“…Savannah sparrows (Passerculus sandwichensis) delay feeding visits to their nestlings when hearing conspecific alarm calls or predators. This behavior is likely reducing predation for both parents and nestlings, but feeding latencies declined under noisy conditions despite the presence of alarm calls or predator songs (Antze and Koper, 2018). A solution to the problems, at least to some extent, would be to adjust acoustic signals in such a way that would reduce masking by anthropogenic noise.…”

The Influence of Transport Infrastructure Development on Bird Diversity and Abundance

“…In recent decades, the detrimental effects of anthropogenic noise on bird diversity have been the focus of numerous studies (Antze, Koper, 2018;Cardoso et al, 2018;Curry et al, 2018a;Kleist et al, 2018;Machado et al, 2017;Mulholland et al, 2018;Polak et al, 2013;Varasteh, 2011;Wiącek et al, 2015). Roadways have various negative effects on bird communities (Freed, Cann, 2009).…”