Anthropogenic noise is a pervasive pollutant that decreases environmental quality by disrupting a suite of behaviors vital to perception and communication. However, even within populations of noise-sensitive species, individuals still select breeding sites located within areas exposed to high noise levels, with largely unknown physiological and fitness consequences. We use a study system in the natural gas fields of northern New Mexico to test the prediction that exposure to noise causes glucocorticoid-signaling dysfunction and decreases fitness in a community of secondary cavity-nesting birds. In accordance with these predictions, and across all species, we find strong support for noise exposure decreasing baseline corticosterone in adults and nestlings and, conversely, increasing acute stressor-induced corticosterone in nestlings. We also document fitness consequences with increased noise in the form of reduced hatching success in the western bluebird (), the species most likely to nest in noisiest environments. Nestlings of all three species exhibited accelerated growth of both feathers and body size at intermediate noise amplitudes compared with lower or higher amplitudes. Our results are consistent with recent experimental laboratory studies and show that noise functions as a chronic, inescapable stressor. Anthropogenic noise likely impairs environmental risk perception by species relying on acoustic cues and ultimately leads to impacts on fitness. Our work, when taken together with recent efforts to document noise across the landscape, implies potential widespread, noise-induced chronic stress coupled with reduced fitness for many species reliant on acoustic cues.

Noise pollution is a novel, widespread environmental force that has recently been shown to alter the behaviour and distribution of birds and other vertebrates, yet whether noise has cumulative, community-level consequences by changing critical ecological services is unknown. Herein, we examined the effects of noise pollution on pollination and seed dispersal and seedling establishment within a study system that isolated the effects of noise from confounding stimuli common to human-altered landscapes. Using observations, vegetation surveys and pollen transfer and seed removal experiments, we found that effects of noise pollution can reverberate through communities by disrupting or enhancing these ecological services. Specifically, noise pollution indirectly increased artificial flower pollination by hummingbirds, but altered the community of animals that prey upon and disperse Pinus edulis seeds, potentially explaining reduced P. edulis seedling recruitment in noisy areas. Despite evidence that some ecological services, such as pollination, may benefit indirectly owing to noise, declines in seedling recruitment for key-dominant species such as P. edulis may have dramatic long-term effects on ecosystem structure and diversity. Because the extent of noise pollution is growing, this study emphasizes that investigators should evaluate the ecological consequences of noise alongside other human-induced environmental changes that are reshaping human-altered landscapes worldwide.

No abstract

Abstract. Noise pollution degrades natural acoustic conditions, potentially interfering with bird communication. However, exactly how noise impacts the ability of the signal receiver to detect and discriminate vocalizations from conspecifics remains understudied in field settings. We performed a natural experiment to determine the effect of noise pollution on the territory-defense behaviors of two emberizid sparrows exposed to carefully constructed playbacks of conspecific intruder songs. Although all birds reacted to the playbacks, response latency increased with noise levels. This suggests that noise interferes with signal reception and may indicate impaired signal discrimination. We place these results in the context of a receiver's "listening area" and the significant impact of noise pollution on this receiver-centric perceptual acoustic range. This work informs conservation efforts and provides a much needed fieldbased examination of the disruptive impact of noise pollution on behaviors directly related to reproduction and fitness.

Birds breeding in heterogeneous landscapes select nest sites by cueing in on a variety of factors from landscape features and social information to the presence of natural enemies. We focus on determining the relative impact of anthropogenic noise on nest site occupancy, compared to amount of forest cover, which is known to strongly influence the selection process. We examine chronic, industrial noise from natural gas wells directly measured at the nest box as well as site-averaged noise, using a well-established field experimental system in northwestern New Mexico. We hypothesized that high levels of noise, both at the nest site and in the environment, would decrease nest box occupancy. We set up nest boxes using a geospatially paired control and experimental site design and analyzed four years of occupancy data from four secondary cavity-nesting birds common to the Colorado Plateau. We found different effects of noise and landscape features depending on species, with strong effects of noise observed in breeding habitat selection of Myiarchus cinerascens, the Ash-throated Flycatcher, and Sialia currucoides, the Mountain Bluebird. In contrast, the amount of forest cover less frequently explained habitat selection for those species or had a smaller standardized effect than the acoustic environment. Although forest cover characterization and management is commonly employed by natural resource managers, our results show that characterizing and managing the acoustic environment should be an important tool in protected area management.

The Northern Mockingbird (Mimus polyglottos) is a successful urban adaptor known to display flexibility in foraging, nesting, and anti-predator behavior. Its vocal behavior is also complex, with a breeding song composed of a wide variety of non-mimetic and mimetic elements, or “syllable types.” We tested the hypothesis that Northern Mockingbird adaptation to urban settings includes changes in its vocal behavior in noisy urban environments. We studied an urban/suburban mockingbird population to test the effect of urban background noise on breeding song frequency and syllable-type composition. Given that urban noise overlaps most strongly with low-frequency vocalizations, a phenomenon known as “signal masking,” we predicted a positive association between noise levels and mockingbird average peak frequency (a measure of vocalization power). We further predicted a positive effect of noise levels on the peak frequency of the lowest-pitched syllable type in a mockingbird’s song, no effect on the peak frequency of the highest-pitched syllable type, and thus a negative effect on mockingbird peak frequency range. Lastly, we predicted a negative effect of background noise on the use of syllable types experiencing heavy signal masking and, conversely, a positive effect on the use of syllable types experiencing minimal signal masking. We found a significant positive effect of noise levels on both average peak frequency and peak frequency of the lowest-pitched syllable type, but no effect on the peak frequency of the highest-pitched syllable type and peak frequency range. In addition, as background noise levels increased, we found significant declines in the percentages of heavily masked syllable types (1–3 kHz) and significant increases in the percentages of syllable types in the 3–5 kHz range; percentages of syllable types >5 kHz were, however, unaffected by background noise. These results were consistent with the hypothesis that Northern Mockingbird breeding songs change in pitch and syllable-type composition in noisy settings, providing further evidence that songs of urban-adapting species differ in noisy environments.

Aircraft noise is pervasive across the USA, including in national parks, but its effects on wildlife remain unresolved. As with other noise sources, aircraft noise may affect species physiology and behaviour by being perceived as a threat, distracting individuals, or degrading the sensory environment. This study aimed to understand the effect of aircraft traffic and associated noise on the richness of bird vocalization activity in a remote national park in the USA. We used a continent‐wide acoustic dataset encompassing over 30:00 h of annotated recordings to identify two geographically similar sites with high rates of bird vocalizations and both high and low rates of aircraft noise. We selected sites in Denali National Park, both of which experience little human presence, and quantified the richness of bird vocalizations before, during and after aircraft events. We present evidence of a community‐level behavioural response to aircraft noise, with increased bird vocalization richness after aircraft events at a site with relatively lower aircraft noise. At the site with low rates of aircraft noise, we found bird vocalization richness did not significantly change during an aircraft event but did increase after an aircraft event. At the site with high rates of aircraft noise, bird vocalization richness did not significantly change during or after an aircraft event. This study provides new insights into wildlife responses to aircraft traffic and associated noise and highlights the importance of noise research in the management of relatively quiet and undisturbed landscapes.

Anthropogenic noise is a complex disturbance known to elicit a variety of responses in wild animals. Most studies examining the effects of noise on wildlife focus on vocal species, although theory suggests that the acoustic environment influences non‐vocal species as well. Common mammalian prey species, like mule deer and hares and rabbits (members of the family Leporidae), rely on acoustic cues for information regarding predation, but the impacts of noise on their behaviour has received little attention. We paired acoustic recorders with camera traps to explore how average daily levels of anthropogenic noise from natural gas activity impacted occupancy and detection of mammalian herbivores in an energy field in the production phase of development. We consider the effects of noise in the context of several physical landscape variables associated with natural gas infrastructure that are known to influence habitat use patterns in mule deer. Our results suggest that mule deer detection probability was influenced by the interaction between physical landscape features and anthropogenic noise, with noise strongly reducing habitat use. In contrast, leporid habitat use was not related to noise but was influenced by landscape features. Notably, mule deer showed a stronger predicted negative response to roads with high noise exposure. This study highlights the complex interactions of anthropogenic disturbance and wildlife distribution and presents important evidence that the effects of anthropogenic noise should be considered in research focused on non‐vocal specialist species and management plans for mule deer and other large ungulates.