How Oil Well Noise Pollution Impacts Songbirds
As human development continues to expand, human-generated noises will likewise increase. Noise pollution impacts the environment in many ways, especially for animals who rely on sound to survive. For example, noise pollution can cause distress and disturb animals’ ability to communicate, look for food, avoid predators, or even care for offspring.
Anthropogenic noise varies in terms of its characteristics, including its loudness and whether it’s continuous or intermittent. In this research, the authors wanted to understand how different sounds associated with oil extraction affect songbird populations and nesting activities. They chose to look at oil extraction because its associated sounds have unique characteristics, including the loud and periodic construction sounds of oil drilling and the chronic, more rhythmic operations sounds of pumpjacks. They focused on four grassland songbirds in North America: the Chestnut-collared Longspur and Sprague’s Pipit (both species are threatened), and the Savannah Sparrow and Vesper Sparrow (these species aren’t considered threatened).
To carry out the study, the researchers built a soundscape to mimic oil extraction noises in an area of Canada that doesn’t have any oil extraction sites. The soundscape included four types of playback sounds: oil drills, generator-powered and power-grid pumpjacks, and sounds labelled “infrastructure only” that didn’t emit any noise but were meant to control for the presence of the sound equipment. The researchers played these sounds at different points in the songbird mating season between 2013-2015, replicating how a songbird might hear them naturally. Throughout the study, they monitored the abundance of all four bird species and their nesting activity throughout the study site.
Over the study period, the authors observed 2,982 Savannah Sparrows, 1,439 Longspurs, 1,022 Pipits, and 239 Vesper Sparrows. Overall, the drilling noise had more negative impacts on bird abundance than pumpjack noises, but not all species were impacted by noise in the same way. For example, Longspurs tended to avoid the immediate area where drilling and pumpjack recordings were played, while Savannah Sparrows avoided drilling noises across the wider study site. Meanwhile, Pipits and Vesper Sparrows were more impacted by the presence of infrastructure (Pipits avoided the infrastructure while Vesper Sparrows seemed to be attracted to it).
As for nesting, drilling noises also seemed to cause more negative effects than pumpjack noises. Across the study site, successful hatchings for Savannah Sparrows declined 35% and for Pipits it declined 85% as a result of drilling noises. Vesper Sparrow nesting success declined simply by the presence of infrastructure.
Finally, the researchers also looked at the body condition of Savannah Sparrow and Longspur hatchlings. Young Savannah Sparrows had a lower condition closer to drilling noise sources, while Longspur hatchlings had an increased body condition in the presence of all noises. In addition, Longspurs tended to have more eggs per nest closer to drilling noise sources.
In Canada, the government requires oil drilling activities to be set a certain distance away from songbird breeding areas during mating season in hopes that the sound levels won’t disturb local bird populations. However, as this study suggests, reducing industrial noise levels alone may not be enough to support songbirds. Instead, birds might be impacted by the suddenness or unpredictability of a sound regardless of its amplitude.
Animal advocates can learn a lot from this study, but one key takeaway is that an effective noise pollution policy must include multiple factors. Therefore, it’s important to work with governments to design oil drilling guidelines that will limit different types of noises, account for songbird breeding seasons, and reduce above-ground infrastructure.