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Anthropogenic noise can create an acoustic environment detrimental for animals that communicate using acoustic signals. Currently, most studies of noise and wildlife come from traffic noise in cities. Less is known about the effects of noise created by industry in natural areas. Songbirds far from cities, but influenced by industry, could be affected by noise, but also are likely to be impacted by changes in vegetation conditions related to industrial development. We described the importance of industrial noise (from facilities and transportation) on occupancy of Lincoln’s Sparrow (Melospiza lincolnii) relative to habitat change caused by vegetation alteration and edge effects. Lincoln’s Sparrows naturally breed in varying seral stages and types of boreal forest. To test the influence of industrial noise, we selected three areas in Northern Alberta, Canada with high, medium, and low levels of industrial development and varying road density. At each area, we deployed a systematic arrangement of autonomous recording units (280 units in total, separated by 600 m) for 3 consecutive days. To measure noise, we developed a method that used the relative noise values extracted from the recordings of 8 frequency-octave bands. We obtained three noise measurements: noise with high energy in the low part of the spectrum (mean 0.5–1 kHz), masking level noise (mean 2–8 kHz), and noise in all frequency octave bands (mean 0.5–16 kHz). Proportion of chronic noise sources explained the highest variation of noise in the environment, and less by traffic noise. We found Lincoln’s Sparrow had a higher occupancy in areas with higher proportion of industrial disturbances, shrubs and grass, and decreased in noisy areas. Masking level noise had a negative effect on Lincoln’s Sparrow occupancy in areas with industrial disturbances, relative to areas with similar changes in vegetation structure, but no noise. Masking noise could indicate limitation in communication as noise increases. Our study amplifies the findings of others that future research should consider not only anthropogenic changes to vegetation in human-altered landscapes, but also human-caused changes to acoustic environments.

Begging brings benefits and costs for nestling birds: it can indicate their needs to their parents, but it can also be a cue used by predators to find the nest. The costs, like many variables related to nest predation, can be specific to what kinds of predators are present and their auditory capabilities. These costs and benefits could also be affected by human noise, as noise could disrupt communication to parents and eavesdropping by predators, although human-produced noise might be easily ignored if predators can hear high-frequency components of the begging. We studied nest predation on a generalist bird, the Red-whiskered Bulbul (Pycnonotus jocosus), in a tropical forest in which there are many kinds of nest predators, including birds, mammals and reptiles. In 20 natural nests in which artificial eggs were placed, and subsequently in 140 artificial nests, we broadcast recordings of begging nestlings, with and without traffic noise, at two volume levels. We hypothesized that playback would increase predation relative to a silent control, and that mixing in traffic noise with the begging would decrease predation, as the begging signal was masked. However, we hypothesized that some predators, particularly small mammals with sensitive high-frequency hearing, might ignore the traffic noise. We found that predation was lowest for the control treatment, and lower for treatments mixed with traffic noise than for those without it. Small mammals, however, showed an unexpected pattern, displaying less nest predation in the treatments with traffic noise. Our results demonstrate the human-associated noise can disturb nest predators and influence which kinds of predators use begging to locate nests.

Human usage of coastal water bodies continues to increase and many invertebrates face a broad suite of anthropogenic stressors (e.g., warming, pollution, acidification, fishing pressure). Underwater sound is a stressor that continues to increase in coastal areas, but the potential impact on invertebrates is not well understood. In addition to masking natural sound cues which may be important for behavioral interactions, there is a small but increasing body of scientific literature indicating sublethal physiological stress may occur in invertebrates exposed to high levels of underwater sound, particularly low frequency sounds such as vessel traffic, construction noise, and some types of sonar. Juvenile and sub-adult blue crabs (Callinectes sapidus) and American lobsters (Homarus americanus) were exposed to simulated low-frequency vessel noise (a signal was low-pass filtered below 1 kHz to ensure low-frequency content only) and mid-frequency sonar (a 1-s 1.67 kHz continuous wave pulse followed by a 2.5 to 4.0 kHz 1-s linear frequency modulated chirp) and behavioral response (the animal’s activity level) was quantified during and after exposure using EthoVision XT™ from overhead video recordings. Source noise was quantified by particle acceleration and pressure. Physiological response to the insults (stress and recovery) were also quantified by measuring changes in hemolymph heat shock protein (HSP27) and glucose over 7 days post-exposure. In general, physiological indicators returned to baseline levels within approximately 48 h, and no observable difference in mortality between treatment and control animals was detected. However, there was a consistent amplified hemolymph glucose signal present 7 days after exposure for those animals exposed to mid-frequency sound and there were changes to C. sapidus competitive behavior within 24 h of exposure to sound. These results stress the importance of considering the impacts of underwater sound among the suite of stressors facing marine and estuarine invertebrates, and in the discussion of management actions such as protected areas, impact assessments, and marine spatial planning efforts.

The Mediterranean monk seal Monachus monachus is one of the most endangered pinnipeds in the world, and is classified as “Endangered” by the International Union for the Conservation of Nature. Any additional knowledge about the species is invaluable to its effective conservation. In the present study, we deployed an autonomous underwater recorder in an important reproductive area of the Mediterranean monk seal in Greece to describe its underwater vocal repertoire. Over the 330 h of continuous recordings, 9231 vocalizations were labelled as potentially produced by Mediterranean monk seals, and 1694 good quality calls were analyzed. We defined 18 call types divided into three main call categories: harmonic, noisy, and pulsative calls. We also described the soundscape in which this endangered species lives and found that human activities around the two main pupping caves had a strong impact on the sonic environment of these seals: the noise level produced by boat traffic was high, and occurred on an hourly (25 to 50 min/hour) and daily basis (10.8 to 16.9 h/day). Such high levels of noise might not only impair the communication of the species, but also impact its survival, as chronic noise can induce physiological stress.

Exposure of wildlife to anthropogenic noise is associated with disruptive effects. Research on this topic has focused on behavioural and physiological responses of animals to noise, with little work investigating links to cognitive function. Neurological processes that maintain cognitive performance can be impacted by stress and sleep disturbances. While sleep loss impairs cognitive performance in Australian magpies, it is unclear whether urban noise, which disrupts sleep, can impact cognition as well. To fill this gap, we explored how environmentally relevant urban noise affected the performance of wild-caught, city-living Australian magpies (Gymnorhina tibicen tyrannica) on a cognitive task battery including associative and reversal learning, inhibitory control, and spatial memory. Birds were housed and tested in a laboratory environment; sample sizes varied across tasks (n=7-9 birds). Tests were conducted over 4 weeks, during which all magpies were exposed to both an urban noise playback and a quiet control. Birds were presented with the entire test battery twice: following exposure to, and in the absence of, an anthropogenic noise playback; however, tests were always performed without noise (playback muted during testing). Magpies performed similarly in both treatments on all four tasks. We also found that prior experience with the associative learning task had a strong effect on performance, with birds performing better on their second round of trials. Like previous findings on Australian magpies tested on the same tasks in the wild under noisy conditions, we could not find any disruptive effects on cognitive performance in a controlled experimental laboratory setting., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

Human activities worldwide are increasingly releasing low-frequency noise into the environment. Anthropogenic noise imposes a novel stress for wild animals and has become an increasing global concern. Many animals have been found to mitigate noise disturbance by modifying their acoustic parameters, yet the calling behaviours of species that breed near airports have not been explored in detail, especially for amphibians. Here, we measured the environmental noise of a swamp close to the runway at Haikou Meilan Airport in China. We also recorded the calls of four anuran species that reproduce in this swamp, and we measured the sound pressure levels of each focal species. These frogs vary in their call amplitude and possess disparate spectral and temporal traits. We show that two frog species characterized by lower frequency calls increase their call frequency when an airplane takes off. Moreover, three anuran species characterized by higher call rates significantly reduce their call rates (or call efforts) in response to airplane flyby. These results suggest that animals' behavioural adaptation to human-made noise may be species specific. Because call frequency and call effort have close relationships with reproductive success, we deduce that such noise-induced behaviour adjustments may influence the fitness of taxa that depend on communication by sound. • Low-frequency frogs increase their call frequency when an aircraft takes off. • Frogs that have more temporal overlap with noise decrease their call activity. • Anuran behavioral responses to human-made noise are species specific. • Aircraft noise may affect the reproductive success of frog species. [ABSTRACT FROM AUTHOR]

Anthropogenic noise has received considerable recent attention, but we know little about the role that sources of natural noise have on wildlife abundance and distributions. Rivers and streams represent an ancient source of natural noise that is widespread and covers much of Earth. We sought to understand the role that whitewater river noise plays on arthropod abundance in riparian habitats across a desert landscape. For two summers, we continuously broadcasted whitewater river noise and spectrally‐altered river noise (shifted upwards in frequency, but maintaining the same temporal profile) to experimentally tease apart the effects of two characteristics of noise – sound levels and background spectral frequency – on arthropod abundances. We used five types of trapping methods, placed across 20 sites within the Pioneer Mountains of Idaho, USA, to collect and identify 151 992 specimens to the order level. We built Bayesian generalized linear mixed‐effects models with noise characteristics and other habitat variables such as riparian vegetation, elevation, temperature, and moonlight. Of the 42 models we built (one for each order‐trap type combination), 26 (62%) indicated a substantial response to at least one noise variable – sound pressure level, background spectral frequency, or an interaction between the two. Fourteen of 17 (82%) arthropod orders responded to noise in some capacity: Araneae, Coleoptera, Collembola, Dermaptera, Hemiptera, Hymenoptera, Lepidoptera, Neuroptera, Opiliones, Orthoptera, Plecoptera, Raphidioptera, Thysanoptera and Trichoptera. Only three groups appeared to be unaffected, Acari, Archaeognatha and Diptera. Results from this study suggest that the natural acoustic environment can shape arthropod abundances both directly and indirectly (via predator–prey relationships). Future work should further examine the role that the indirect effects of noise play in food webs. Natural noise should be considered an important ecological niche axis, especially as we continue to alter natural acoustic environments and replace them with anthropogenic ones. [ABSTRACT FROM AUTHOR]

Anthropogenic noise pollution is an emerging global threat to fish populations. Among a suite of deleterious effects, noise can potentially impede reproductive success in some fishes by masking their mate advertisement vocalizations. Using the plainfin midshipman fish, Porichthys notatus , a marine toadfish that produces a distinctive 'hum' during courtship, we investigated how noise affects male vocalizations and spawning success in the wild. We recorded nesting males for 3 days and measured the frequency (i.e. pitch), amplitude and duration of their vocalizations before, during and after exposure to artificial noise (∼118 Hz tone). We also counted eggs in nests exposed to 10 days of artificial noise versus control nests that were not exposed to artificial noise. Males exposed to noise produced fewer vocalizations, reduced the frequency of vocalizations and increased the amplitude of their mating hum (Lombard effect). However, chronic artificial noise exposure did not significantly affect spawning success, suggesting that the Lombard effect allowed males to sustain clear advertisement signals when competing with a relatively weak artificial noise source. Future studies are needed to determine whether such vocal adjustments incur costs for males, and how common anthropogenic noises, such as boat engines, affect spawning and reproductive success. • Artificial noise elicited an amplitude increase in mate advertisement vocalizations. • Artificial noise elicited peak frequency decreases in three different vocalizations. • All vocalizations occurred less often in the presence of artificial noise. • Exposure to artificial noise for 10 days did not appear to affect spawning success. [ABSTRACT FROM AUTHOR]

Most research on how birds adapt to urban environments has been conducted in cities in developed (Global North) countries, which differ structurally and acoustically from cities in developing (Global South) countries; therefore, optimal behavioural strategies of animals living in urban landscapes may also differ based on the economic status of the country in which they live. We studied Grenada's house wren population (Troglodytes aedon grenadensis) to investigate song plasticity of this subspecies in response to urbanisation. Grenada, a Small Island Developing State in the Caribbean, is under increasing pressure from tourism, urbanisation, and climate change, and little is known about its avian community. We recorded 33 Grenada house wrens at five urban and five rural sites across Grenada, and analysed effects of urbanisation using generalised estimating equations. Grenada house wrens used a mix of strategies to compensate for urbanisation. In urban habitats, house wrens sang shorter introductions, faster trills, and increased the low frequencies of the introduction and the whole song. Grenada's house wrens use some unusual song alterations in urban environments, emphasising the importance of studying animal behaviour in Small Island Developing States to help us understand the unique anthropogenic pressures faced by species in these vulnerable regions. [ABSTRACT FROM AUTHOR]

Anthropogenic noise is a pervasive environmental feature across both urban and non-urban habitats and presents a novel challenge especially for acoustically communicating species. While it is known that some species adjust acoustic signals to communicate more effectively in noisy habitats, we know very little about how the receivers of these signals might be impacted by anthropogenic noise. Here, we investigated female and male Litoria fallax frogs' ability to distinguish between high- and low-quality acoustic signals during the presence of background traffic noise and without. We performed a controlled behavioural experiment whereby frogs were presented with simultaneously broadcasted attractive and unattractive calls from opposing directions, once with background traffic noise and once without. We found that females in particular chose the unattractive call significantly more often (and males significantly less often) when noise was being broadcast. This indicates that anthropogenic noise potentially affects receiver responses to acoustic signals, even when calls are not acoustically masked, with potential consequences for maladaptive mating behaviours and population outcomes. [ABSTRACT FROM AUTHOR]

From midnight of 26 March 2020, New Zealand became one of the first countries to enter a strict lockdown to combat the spread of COVID‐19. The lockdown banned all non‐essential services and travel both on land and sea. Overnight, the country's busiest coastal waterway, the Hauraki Gulf Marine Park, became devoid of almost all recreational and non‐essential commercial vessels. An almost instant change in the marine soundscape ensued, with ambient sound levels in busy channels dropping nearly threefold the first 12 h. This sudden drop led fish and dolphins to experience an immediate increase in their communication ranges by up to an estimated 65%. Very low vessel activity during the lockdown (indicated by the presence of vessel noise over the day) revealed new insights into cumulative noise effects from vessels on auditory masking. For example, at sites nearer Auckland City, communication ranges increased approximately 18 m (22%) or 50 m (11%) for every 10% decrease in vessel activity for fish and dolphins, respectively. However, further from the city and in deeper water, these communication ranges were increased by approximately 13 m (31%) or 510 m (20%). These new data demonstrate how noise from small vessels can impact underwater soundscapes and how marine animals will have to adapt to ever‐growing noise pollution. [ABSTRACT FROM AUTHOR]

Birdsong is an important feature that mediates several aspects of bird reproduction, such as mate choice, territory defense, and individual recognition. Any factor that impairs vocal transmission through the environment may also impair conspecific recognition and thus reduce the effectiveness of reproduction. In this scenario, birds inhabiting urban environments might be subject to different selective pressures on their vocal amplitude due to acoustic barriers in the song transmission, such as excessive background noise and abnormal atmospheric absorption of sound. Therefore, we measured the amplitude of the song of the Southern House Wren (Troglodytes aedon musculus), to determine the relationships between the variation in vocal intensity and the environmental features. We expect divergence in vocal amplitude according to the noise levels, with song intensity responding to the increasing noise. We found that birds sang with higher amplitude in areas where traffic noise is elevated. Multiple linear regression showed a positive relationship between song amplitude and background noise and a negative relationship between vocal intensity and atmospheric attenuation. Our findings suggest a direct influence of urban environmental structures on the vocal behavior of wrens, which may challenge the effectiveness of communication between subjects and affect the behavioral ecology of the species. [ABSTRACT FROM AUTHOR]

Some birds in noisy areas produce songs with higher frequency and/or amplitude and altered timing compared to individuals in quiet areas. These changes may function to increase the efficacy of acoustic signals by reducing masking by noise. We collected audio recordings of red-winged blackbirds and measured noise levels. We found that males in noisier places produced songs with fewer syllables and slower repeat rate of elements in some components (rattles). Birds may also improve the efficacy of communication in noise by increasing usage of other signaling modalities. Red-winged blackbirds also perform a visual display in different intensities while singing. We also tested whether this species performs the visual display in different intensities according to current noise levels, and predicted that if the efficacy of songs is impaired in noisy places, males would compensate by performing a more intense visual display. For this, we also collected visual recordings from the same males from which we obtained acoustic recordings. We found no association between acoustic noise and the intensity of the visual display; thus, our results do not support the idea that males are using the visual display as a backup signal to communicate under acoustic noise. We discuss some possible explanations of this negative finding and for the observed noise-related changes in song length and rattle rate in the context of communication under noise.

The increasing underwater noise generated by anthropogenic activities has been widely recognized as a significant and pervasive pollution in the marine environment. Marine mussels are a family of sessile bivalves that attach to solid surfaces via the byssal threads. They are widely distributed along worldwide coastal areas and are of great ecological and socio-economic importance. Studies found that anthropogenic noise negatively affected many biological processes and/or functions of marine organisms. However, to date, the potential impacts of anthropogenic noise on mussel byssal attachment remain unknown. Here, the thick shell mussels Mytilus coruscus were exposed to an ambient underwater condition (∼50 dB re 1 μPa) or the playbacks of pile-driving noise (∼70 or ∼100 dB re 1 μPa) for 10 days. Results showed that the noise significantly reduced the secretion of byssal threads (e.g., diameter and volume) and weakened their mechanical performances (e.g., strength, extensibility, breaking stress, toughness and failure location), leading to a 16.95–44.50% decrease in mussel byssal attachment strength. The noise also significantly down-regulated the genes expressions of seven structural proteins (e.g., mfp-1, mfp-2, mfp-3, mfp-6, preCOL-P, preCOL-NG, and preCOL-D) of byssal threads, probably mediating the weakened byssal attachment. Given the essential functions of strong byssal attachment, the findings demonstrate that the increasing underwater anthropogenic noise are posing a great threat to mussel population, mussel-bed community and mussel aquaculture industry. We thus suggest that future work is required to deepen our understanding of the impacts of anthropogenic noise on marine invertebrates, especially these with limited locomotion ability, like bivalves.

Chronic low-frequency noise from commercial shipping is a worldwide threat to marine animals that rely on sound for essential life functions. Although the U.S. National Oceanic and Atmospheric Administration recognizes the potential negative impacts of shipping noise in marine environments, there are currently no standard metrics to monitor and quantify shipping noise in U.S. marine waters. However, one-third octave band acoustic measurements centered at 63 and 125 Hz are used as international (European Union Marine Strategy Framework Directive) indicators for underwater ambient noise levels driven by shipping activity. We apply these metrics to passive acoustic monitoring data collected over 20 months in 2016–2017 at five dispersed sites throughout the U.S. Exclusive Economic Zone: Alaskan Arctic, Hawaii, Gulf of Mexico, Northeast Canyons and Seamounts Marine National Monument (Northwest Atlantic), and Cordell Bank National Marine Sanctuary (Northeast Pacific). To verify the relationship between shipping activity and underwater sound levels, vessel movement data from the Automatic Identification System (AIS) were paired to each passive acoustic monitoring site. Daily average sound levels were consistently near to or higher than 100 dB re 1 μPa in both the 63 and 125 Hz one-third octave bands at sites with high levels of shipping traffic (Gulf of Mexico, Northeast Canyons and Seamounts, and Cordell Bank). Where cargo vessels were less common (the Arctic and Hawaii), daily average sound levels were comparatively lower. Specifically, sound levels were ∼20 dB lower year-round in Hawaii and ∼10-20 dB lower in the Alaskan Arctic, depending on the season. Although these band-level measurements can only generally facilitate differentiation of sound sources, these results demonstrate that international acoustic indicators of commercial shipping can be applied to data collected in U.S. waters as a unified metric to approximate the influence of shipping as a driver of ambient noise levels, provide critical information to managers and policy makers about the status of marine environments, and to identify places and times for more detailed investigation regarding environmental impacts.

Levels of anthropogenic noise and artificial light at night (ALAN) are rapidly rising on a global scale. Both sensory pollutants are well known to affect animal behavior and physiology, which can lead to substantial ecological impacts. Most studies on noise or light pollution to date have focused on single stressor impacts, studying both pollutants in isolation despite their high spatial and temporal co-occurrence. However, few studies have addressed their combined impact, known as multisensory pollution, with the specific aim to assess whether the interaction between noise and light pollution leads to predictable, additive effects, or less predictable, synergistic or antagonistic effects. We carried out a systematic review of research investigating multisensory pollution and found 28 studies that simultaneously assessed the impact of anthropogenic noise and ALAN on animal function (e.g., behavior, morphology or life-history), physiology (e.g., stress, oxidative, or immune status), or population demography (e.g., abundance or species richness). Only fifteen of these studies specifically tested for possible interactive effects when both sensory pollutants were combined. Four out of eight experimental studies revealed a significant interaction effect, in contrast to only three out seven observational studies. We discuss the benefits and limitations of experimental vs. observational studies addressing multisensory pollution and call for more specific testing of the diverse ways in which noise and light pollution can interact to affect wildlife.

Soundscapes offer rich descriptions of composite acoustic environments. Characterizing marine soundscapes simply through sound levels results in incomplete descriptions, limits the understanding of unique features, and impedes meaningful comparisons. Sources that contribute to sound level metrics shift in time and space with changes in biological patterns, physical forces, and human activity. The presence of a constant or chronic source is often interwoven with episodic sounds. Further, the presence and intensity of sources can influence other sources, calling for a more integrated approach to characterizing soundscapes. Here, we illustrate this complexity using data from a national-scale effort, the Sanctuary Soundscape Monitoring Project (SanctSound), an initiative designed to support collection of biological, environmental, and human use data to compliment the interpretation of sound level measurements. Using nine examples from this diverse dataset we demonstrate the benefit of integrating source identification and site features to interpret sound levels across a diversity of shallow water marine soundscapes (

Increasing levels of anthropogenic underwater noise have caused concern over their potential impacts on marine life. Offshore renewable energy developments and seismic exploration can produce impulsive noise which is especially hazardous for marine mammals because it can induce auditory damage at shorter distances and behavioral disturbance at longer distances. However, far-field effects of impulsive noise remain poorly understood, causing a high level of uncertainty when predicting the impacts of offshore energy developments on marine mammal populations. Here we used a 10-year dataset on the occurrence of coastal bottlenose dolphins over the period 2009–2019 to investigate far-field effects of impulsive noise from offshore activities undertaken in three different years. Activities included a 2D seismic survey and the pile installation at two offshore wind farms, 20–75 km from coastal waters known to be frequented by dolphins. We collected passive acoustic data in key coastal areas and used a Before-After Control-Impact design to investigate variation in dolphin detections in areas exposed to different levels of impulsive noise from these offshore activities. We compared dolphin detections at two temporal scales, comparing years and days with and without impulsive noise. Passive acoustic data confirmed that dolphins continued to use the impact area throughout each offshore activity period, but also provided evidence of short-term behavioral responses in this area. Unexpectedly, and only at the smallest temporal scale, a consistent increase in dolphin detections was observed at the impact sites during activities generating impulsive noise. We suggest that this increase in dolphin detections could be explained by changes in vocalization behavior. Marine mammal protection policies focus on the near-field effects of impulsive noise; however, our results emphasize the importance of investigating the far-field effects of anthropogenic disturbances to better understand the impacts of human activities on marine mammal populations.

Passive acoustic data collection has grown exponentially over the past decade resulting in petabytes of data that document our ocean soundscapes. This effort has resulted in two big data challenges: (1) the curation, management, and global dissemination of passive acoustic datasets and (2) efficiently extracting critical information and comparing it to other datasets in the context of ecosystem-based research and management. To address the former, the NOAA National Centers for Environmental Information recently established an archive for passive acoustic data. This fast-growing archive currently contains over 100 TB of passive acoustic audio files mainly collected from stationary recorders throughout waters in the United States. These datasets are documented with standards-based metadata and are freely available to the public. To begin to address the latter, through standardized processing and centralized stewardship and access, we provide a previously unattainable comparison of first order sound level-patterns from archived data collected across three distinctly separate long-term passive acoustic monitoring (PAM) efforts conducted at regional and national scales: NOAA/National Park Service Ocean Noise Reference Station Network, the Atlantic Deepwater Ecosystem Observatory Network, and the Sanctuary Soundscape Monitoring Project. Nine sites were selected from these projects covering the Alaskan Arctic, Northeast and Central Pacific, Gulf of Mexico, Caribbean Sea, and Mid and Northwest Atlantic. Sites could generally be categorized into those strongly influenced by anthropogenic noise (e.g., vessel traffic) and those that were not. Higher sound levels, specifically for lower frequencies (

Animals rely on both personal and social information about danger to minimize risk, yet environmental conditions constrain information. Both visual obstructions and background noise can reduce detectability of predators, which may increase reliance on social information, such as from alarm calls. Furthermore, a combination of visual and auditory constraints might greatly increase reliance on social information, because the loss of information from one source cannot be compensated by the other. Testing these possibilities requires manipulating personal information while broadcasting alarm calls. We therefore experimentally tested the effects of a visual barrier, traffic noise, and their combination on the response of Australian magpies, Cracticus tibicen, to heterospecific alarm calls. The barrier blocked only visual cues, while playback of moderate traffic noise could mask subtle acoustic cues of danger, such as of a predator's movement, but not the alarm-call playback. We predicted that response to alarm calls would increase with either visual or acoustic constraint, and that there would be a disproportionate response when both were present. As predicted, individuals responded more strongly to alarm calls when there was a visual barrier. However, moderate traffic noise did not affect responses, and the effect of the visual barrier was not greater during traffic-noise playback. We conclude that a reduction of personal, visual information led to a greater reliance on social information from alarm calls, confirming indirect evidence from other species. The absence of a traffic-noise effect could be because in Australian magpies hearing subtle cues is less important than vision in detecting predators. Animals may detect predators themselves or respond to alarm calls from others. We tested whether restrictions on personal detection of predators by sight or sound increased responsiveness of Australian magpies to alarms from noisy miners. A visual barrier prompted stronger responses to alarms, but moderate traffic noise did not. Magpies therefore rely more on alarms from others when they have a poor view, but moderate traffic noise appeared not to affect their judgment of danger. [ABSTRACT FROM AUTHOR]

The extent of artificial night light and anthropogenic noise (i.e., "light" and "noise") impacts is global and has the capacity to threaten species across diverse ecosystems. Existing research involving impacts of light or noise has primarily focused on noise or light alone and single species; however, these stimuli often co‐occur and little is known about how co‐exposure influences wildlife and if and why species may vary in their responses. Here, we had three aims: (1) to investigate species‐specific responses to light, noise, and the interaction between the two using a spatially explicit approach to model changes in abundance of 140 prevalent bird species across North America, (2) to investigate responses to the interaction between light exposure and night length, and (3) to identify functional traits and habitat affiliations that explain variation in species‐specific responses to these sensory stimuli with phylogenetically informed models. We found species that responded to noise exposure generally decreased in abundance, and the additional presence of light interacted synergistically with noise to exacerbate its negative effects. Moreover, the interaction revealed negative emergent responses for several species that only reacted when light and noise co‐occurred. Additionally, an interaction between light and night length revealed 47 species increased in abundance with light exposure during longer nights. In addition to modifying behavior with optimal temperature and potential foraging opportunities, birds might be attracted to light, yet suffer inadvertent physiological consequences. The trait that most strongly related to avian response to light and noise was habitat affiliation. Specifically, species that occupy closed habitat were less tolerant of both sensory stressors compared to those that occupy open habitat. Further quantifying the contexts and intrinsic traits that explain how species respond to noise and light will be fundamental to understanding the ecological consequences of a world that is ever louder and brighter. [ABSTRACT FROM AUTHOR]

Climate change is projected to cause the Arctic soundscape to become noisier due to sea ice loss and increased anthropogenic activity. Many studies on underwater sound levels have been conducted in the western North American Arctic and Fram Strait, but the rest of the Arctic is full of geographic gaps. Han et al. (2021, https://doi.org/10.1029/2021gl093097) published a study in Geophysical Research Letters on underwater sound levels in the East Siberian Sea, providing the first estimates of seasonal trends and the natural and anthropogenic drivers of underwater sound levels in this region. This is an excellent first step in filling geographic gaps in the Russian Arctic, and I call on other researchers to continue to fill these geographic gaps throughout the Arctic so that we can set a baseline and study changes to underwater sound levels being caused directly and indirectly by climate change. Plain Language Summary: The Arctic marine environment can be one of the quietest on Earth, particularly under solid sea ice. Climate change is causing sea ice to melt at an alarming rate and is also allowing increased human shipping activity. Both sea ice loss and increased shipping activity will likely lead to a noisier environment underwater in the Arctic. Many studies have examined how loud the underwater environment is in the Arctic of western North America and between East Greenland and Svalbard, but there are many areas throughout the Arctic with no studies. Han et al. (2021, https://doi.org/10.1029/2021gl093097) just published the first study on the loudness of the underwater environment in the East Siberian Sea. This study fills an important gap in our knowledge, and I call on other researchers to continue expanding studies into areas of the Arctic where we have no data on underwater sound levels. More studies will help us track the changes in underwater sound levels being caused by climate change. Key Points: Han et al. (2021) published a study in Geophysical Research Letters on underwater sound levels in the East Siberian SeaI place this study in the context of broader effort to establish baselines of underwater sound levels in the ArcticI call on researchers to continue filling geographic gaps in studies of underwater sound levels, particularly in the Russian Arctic [ABSTRACT FROM AUTHOR]

Acoustic behaviour is a key component of specialized foraging tactics for many aquatic species, especially cetaceans. However, in recent decades the natural environment has been increasingly exposed to a variety of anthropogenic noise sources, with the potential to impact natural foraging specializations dependent on acoustic communication. Here we evaluated whether boat noise has the potential to impact a rare foraging tactic used by individuals from a small population of the vulnerable Lahille's bottlenose dolphin (Tursiops truncatus gephyreus) specialized in cooperation with artisanal fishers in southern Brazil. We tested whether the presence of boats changed the acoustic behaviour of dolphins when engaged in this cooperative foraging. We found that whistles and echolocation click rates were lower when boats were present, suggesting that cooperative foraging may potentially be reduced or interrupted by the presence of boats. Whistle parameters changed in response to the number, type and speed of boats, indicating a behavioural change and acoustic masking. Locally, our results reinforce the need for boat traffic regulations to minimize their impacts on these endangered dolphins and their rare cooperative tactic. From a broad perspective, we demonstrate how nonlethal impacts such as vessel disturbance can manifest subtle changes in animals' natural behaviour and, in this case, present an insidious threat to a unique foraging specialization. [ABSTRACT FROM AUTHOR]

Tolerance to human‐induced environmental stressors is known to contribute to the spread and success of invasive species but their response to anthropogenic noise has still to be explored. Anthropogenic noise might modulate the trophic impact of invasive species and their competitiveness against native species.We used an ecological approach through the derivation of the functional response to test whether the strength of the trophic interaction between the invasive pumpkinseed sunfish and Chaoborus larvae was influenced by motorboat noise, with or without pre‐exposure.Boat noise decreased maximum feeding rate in the fish that never experienced boat noise before, resulting in a lower functional response compared to the ambient noise condition. We hypothesised that fish were distracted and reallocated a part of their finite attention to this new acoustic stimulus at the expense of prey processing.The distraction effect weakened with repeated exposure suggesting a habituation process. Although we cannot exclude persistent adjustments in behaviour, we did not find evidence for altered predation by fish pre‐exposed to boat noise.Pumpkinseed sunfish did not exhibit clear symptoms of a behavioural stress response. Chaoborus movements were more numerous under boat noise but this was unlikely to influence trophic interaction strength relative to fish behaviour. Local species might experience increased trophic competition if they are disturbed and do not habituate contrary to invasive species. [ABSTRACT FROM AUTHOR]

Management interventions to reduce human–wildlife conflict can have unintended consequences for non‐target species. Acoustic deterrent devices (ADDs) are used globally by the aquaculture sector. However, the potential for these sound emissions to impact non‐target species, such as cetaceans, has not yet been quantified at population relevant spatial scales.To better understand the extent of potential impacts on cetaceans, such as harbour porpoises, we used acoustic modelling to investigate levels of ADD noise throughout the west coast of Scotland and across a Special Area of Conservation (SAC) for this species.Using an energy‐flux acoustic propagation model and data on aquaculture sites known to be using ADDs, we predicted the spatial extent of ADD noise on the Scottish west coast from 1 February 2017 to 31 January 2018. Noise maps were produced to determine the risk of auditory impairment for harbour porpoises under a range of scenarios which assumed single or multiple ADDs and simultaneous use across all sites.The acoustic propagation model performed well when tested against field measurements up to 5 km, with 98% of sound exposure level (SEL) predictions within ±10% of the measurements. Predictions of SELs over a 24‐hr period suggested extensive temporary hearing loss zones (median radius: ~28 km) for harbour porpoises around aquaculture sites. Assuming a single device at each site, 23% of the harbour porpoise SAC was predicted to be exposed to ADD noise sufficient to induce a temporary threshold shift, and under the worst‐case scenario (multiple, continuously running devices per site with an aggregate duty cycle of 100%), levels exceeding permanent threshold shift could reach 0.9% of the SAC.Policy implications. This study highlights the potential for 'collateral damage' from interventions such as acoustic deterrent devices (ADDs) which are intended to reduce human–wildlife conflicts with pinnipeds but may affect the long‐term health and habitat use of non‐target species. This is especially true for harbour porpoises which are protected under the EU and UK Habitats Regulations. The aquaculture industry, policymakers and regulators in countries where ADDs are used should consider these findings when attempting to mitigate pinniped depredation. [ABSTRACT FROM AUTHOR]

Anthropogenic noise is a pervasive and increasing source of disturbance to wildlife. Marine mammals exhibit behavioural and physiological responses to naval sonar and other sound sources. The lost foraging opportunities and elevated locomotor effort associated with sonar disturbance likely carry energetic costs, which may lead to population‐level consequences.We modelled the energetic costs associated with behavioural responses using (a) empirical datasets of cetacean feeding rates and prey characteristics and (b) allometry of swimming performance and metabolic rates.We applied our model to compare the short‐term (i.e. the scale of the disturbance response; hours to days) energetic costs of a variety of observed behavioural responses. Efficient foragers (e.g. baleen whales) incur a greater relative energetic cost for mild behavioural responses as compared to the most extreme observed response for larger odontocetes (e.g. beaked whales). Energetic costs are more sensitive to lost feeding opportunities than increased energy expenditure from elevated locomotor effort.To scale up from short‐term costs to long‐term effects (months to years), future research should address individuals' capacity to compensate for energetic losses as well as energetic thresholds for demographic rates (survival, fecundity). We discuss how relative energetic costs correlate with species' pace of life and the implications for conservation planning.Synthesis and applications. Current approaches towards understanding the Population Consequences of Disturbance (PCoD) often must rely on expert opinion due to data deficiency. Our model provides an empirical method for linking behaviour to energetics, which is critical for managers to make informed decisions on actions that may affect marine mammal species. Furthermore, our model is applicable to other forms of disturbance, such as vessel traffic or seismic exploration, and our scaling approach enables risk projections for understudied species. ​ [ABSTRACT FROM AUTHOR]

As anthropogenic noise increases globally, there is an urgent need to understand how noise impacts ecological communities. Recent literature shows both terrestrial and aquatic species exhibit myriad responses to noise, including physiological stress, higher mortality, and habitat avoidance. Most studies focus on the responses of single species from terrestrial or marine habitats, with fewer examining freshwater systems and implications for trophic relationships. We used a laboratory study to investigate whether highland stonerollers (Campostoma spadecium), an algivorous freshwater fish, avoid recreational boat noise and thus graze preferentially in quieter areas. For seven groups of eight fish, we recorded the tank position (near, mid, far) of individual fish relative to a speaker playing intermittent boat noise (noise trials) and a mock speaker playing no noise (quiet trials) over a 3-day period. After each trial, we measured the proportion of algae grazed from tiles placed in each section of the tank. Our results show that fish did not avoid the noise speaker compared to fish near the mock speaker in the near section of the tank, but they were found in higher proportions in the quietest section of the tank (mid) during noise trials. There was no difference in the amount of algae consumed in any section when comparing quiet to noisy trials. Thus, our study did not indicate that recreational boat noise elicited clear avoidance behavior or impacted algal coverage. However, these results should be interpreted cautiously since sensitivity to noise pollution varies according to stimulus and species, and these results represent only one species from one geographic location. [ABSTRACT FROM AUTHOR]

In one of a series of studies of noise-induced hearing loss to determine the frequency-dependent susceptibility of California sea lions (Zalophus californianus) to temporary hearing threshold shift (TTS), two subjects were exposed for 60 min to two different fatiguing sounds. These were continuous one-sixth-octave noise bands (NBs), centered at 2 kHz, at sound pressure levels (SPLs) of 138 to 167 dB re 1 μPa (resulting in sound exposure levels [SELs] of 174 to 203 dB re 1 μPa2s), and at 4 kHz, at SPLs of 133 to 169 dB re 1 μPa (resulting in SELs of 169 to 205 dB re 1 μPa2s). Using a psychoacoustic technique, TTSs were quantified at 2, 2.8, 4.2, 5.6, and 8 kHz (at the center frequency of each NB, at half an octave higher, and at one octave higher). After exposure to both NBs, higher SELs resulted in greater TTS at all hearing frequencies that were tested. TTSs and hearing recovery patterns were similar in both sea lions. The effect of fatiguing sound duty cycle on TTS was investigated with the NB at 4 kHz and with 1.6-s signal duration, at a mean SPL of 169 dB re 1 μPa. Duty cycle reduction from 100 to 90% resulted in the largest decrease in TTS, and no TTS occurred at duty cycles < 60%. The equal-energy hypothesis was investigated with the NB at 4 kHz: five combinations of SPL and exposure duration that resulted in the same SEL (197 dB re 1 μPa2s) produced similar initial TTSs in both sea lions. Susceptibility of California sea lions to TTS is higher than previously believed; for sounds around 2 and 4 kHz, it is similar to the susceptibility of harbor seals (Phoca vitulina). These data will contribute towards the development of an evidence-based underwater sound weighting function for the protection of Otariidae. [ABSTRACT FROM AUTHOR]

The underwater soundscape is an important ecological element affecting numerous aquatic animals, in particular dolphins, which must identify salient cues from ambient ocean noise. In this study, temporal variations in the soundscape of Jiaotou Bay were monitored from February 2016 to January 2017, where a population of Indo‐Pacific humpback dolphins (Sousa chinensis) has recently been a regular sighting. An autonomous acoustic recorder was deployed in shallow waters, and 1/3‐octave band sound pressure levels (SPLs) were calculated with central frequencies ranging from 25 Hz to 40 kHz, then were grouped into 3 subdivided bands via cluster analysis. SPLs at each major band showed significant differences on a diel, fishing‐related period, seasonal, and tidal phase scale. Anthropogenic noise generated by passing ships and underwater explosions were recorded in the study area. The fish and dolphin acoustic activities both exhibited diel and seasonal variations, but no tidal cycle patterns. A negative significant relationship between anthropogenic sound detection rates and dolphin detection rates were observed, and fish detection rates showed no effect on dolphin detection rates, indicating anthropogenic activity avoidance and no forced foraging in dolphins in the study area. The results provide fundamental insight into the acoustic dynamics of an important Indo‐Pacific humpback dolphin habitat within a coastal area affected by a rapid increase in human activity, and demonstrate the need to protect animal habitat from anthropogenic noises. [ABSTRACT FROM AUTHOR]

Marine noise is recognised as a growing threat that can induce maladaptive behavioural changes in many aquatic animals, including fishes. The plainfin midshipman is a soniferous fish with a prolonged breeding period, during which males produce tonal hums that attract females, and grunts and growls during agonistic interactions. In this study, we used acoustic recordings to assess the effects of boat noise on the presence, peak frequencies, and durations of plainfin midshipman calls in the wild. We found that all three call types were less likely to occur, and the peak frequencies of hums and grunts increased in the presence of boat noise. We also show that loud and quiet boat noise affected plainfin midshipman vocalizations similarly. As anthropogenic noise is likely to increase in the ocean, it will be important to understand how such noise can affect communication systems, and consequently population health and resiliency. • The effect of real boat noise on wild plainfin midshipman vocalizations was assessed. • The presence of bot noise decreased the number of hums at dawn and dusk, and the number of growls at dawn. • The presence of boat noise decreased the number of grunts, pooled between dawn and dusk. • The presence of boat noise increased the peak frequency of hums at dawn, and grunts at dusk. [ABSTRACT FROM AUTHOR]

Abstract Background Urbanisation has been shown to influence many aspects of animal vocal communication. Much attention has been paid to anthropogenic noise, which is often described as one of the most challenging disturbances for urban dwellers. While a large body of literature describes associations between vocal behavior of avian populations and background noise level, most of these studies were conducted on species with relatively simple songs and small repertoire sizes. This study focuses on the song thrush, Turdus philomelos, a common Eurasian songbird with a complex singing style and large syllable repertoire. Our objective was to determine whether frequency, repertoire and temporal organisation of song parameters vary between birds inhabiting urban and adjacent forest habitats in which ambient noise levels differ. Results Songs of urban males were found to be more complex than in conspecifics from natural forest populations. Urban dwellers possessed greater syllable repertoires and repeated syllable sequences more often. In addition, they used a smaller proportion of whistles and a higher proportion of twitter syllables when singing compared to the nonurban males. Moreover, we found significant differences in the minimum and peak frequency of the whistle syllable between studied populations. Conclusions These findings may be an example of adaptation of acoustic communication in noisy urban environments, but we also discuss other possible explanations. We emphasize the need for further investigation into the relationships between birdsong and habitat characteristics, male quality, population density and ambient noise level in populations occupying urban and nonurban habitats.

Anthropogenic noise is a growing threat to marine life due to the incrementation of human activity in the marine environment. In Europe, the Directive 2008/56/EC of the European Parliament and of the Council was published with the aim of establishing a framework for community action in the field of marine environmental policy. The directive introduces underwater acoustic energy, as detailed in Descriptor 11, and stipulates that the member states should set the threshold levels at which a good environmental status can be achieved by means of long-term monitoring campaigns. This research presents the results of a long-term underwater noise monitoring campaign with a duration of three years in the port of Cartagena located on the south-eastern coast of Spain, focusing on the monthly and annual variation patterns of low-frequency continuous noise. The acquired data are classified according to the source of the acoustic noise into shipping, other anthropogenic, and natural noise measurements. These three groups of measurements are processed in order to obtain one-third octave band levels centered at 63 and 125 Hz, as well as the overall bandwidth of unweighted Sound Pressure Level (SPL). The analysis of the measurements shows an increase in the annual average overall band of 4 and 3 dB of the natural and shipping noise, respectively, from 2013 to 2015. This monitoring campaign provides accurate acoustic values to establish threshold levels to achieve good environmental status and recommendations to conduct monitoring programs and regulations to control underwater noise pollution.

Vessel traffic is one of the major sources of underwater anthropogenic noise. Dolphins can modify their vocal repertoire, especially whistles, in presence of vessels to facilitate their communication. Acoustic data were collected (sampling rate 96 kHz) in La Paz Bay, Gulf of California, Mexico. Whistle rate and parameters of the coastal and oceanic ecotypes of common bottlenose dolphins (Tursiops truncatus) were measured in absence of vessels and in presence of moving small vessels (size 5–10 m). The peak noise difference was calculated between the two frequency bands dominated by the whistles (2000–20,000 Hz) and the small vessel (500–2000 Hz). In presence of vessels the oceanic ecotype decreased whistle frequencies while the coastal ecotype increased them. Both ecotypes raised whistle frequencies with the decreasing of the peak noise difference. The differences in habitat and group structure could have driven the two ecotypes to react in a different way to the vessel presence.

One of the last pristine marine soundscapes, the Arctic, is exposed to increasing anthropogenic activities due to climate-induced decrease in sea ice coverage. In this study, we combined movement and behavioral data from animal-borne tags in a controlled sound exposure study to describe the reactions of narwhals, Monodon monoceros, to airgun pulses and ship noise. Sixteen narwhals were live captured and instrumented with satellite tags and Acousonde acoustic-behavioral recorders, and 11 of them were exposed to airgun pulses and vessel sounds. The sound exposure levels (SELs) of pulses from a small airgun (3.4 L) used in 2017 and a larger one (17.0 L) used in 2018 were measured using drifting recorders. The experiment was divided into trials with airgun and ship-noise exposure, intertrials with only ship-noise, and pre- and postexposure periods. Both trials and intertrials lasted ∼4 h on average per individual. Depending on the location of the whales, the number of separate exposures ranged between one and eight trials or intertrials. Received pulse SELs dropped below 130 dB re 1 μPa2 s by 2.5 km for the small airgun and 4–9 km for the larger airgun, and background noise levels were reached at distances of ∼3 and 8–10.5 km, respectively, for the small and big airguns. Avoidance reactions of the whales could be detected at distances >5 km in 2017 and >11 km in 2018 when in line of sight of the seismic vessel. Meanwhile, a ∼30% increase in horizontal travel speed could be detected up to 2 h before the seismic vessel was in line of sight. Applying line of sight as the criterion for exposure thus excludes some potential pre-response effects, and our estimates of effects must therefore be considered conservative. The whales reacted by changing their swimming speed and direction at distances between 5 and 24 km depending on topographical surroundings where the exposure occurred. The propensity of the whales to move towards the shore increased with increasing exposure (i.e., shorter distance to vessels) and was highest with the large airgun used in 2018, where the whales moved towards the shore at distances of 10–15 km. No long-term effects of the response study could be detected.

This paper presents practice-based research on ecoacoustics, ocean soundscapes and anthropogenic noise. It explores creative strategies to the introduction, experience and performance of ocean soundscapes in artistic creation. As ocean soundscapes are increasingly a topic of concern globally, they become a crucial tool to foster an emotional affinity between people and natural environments. This research questions how to convey the experience of oceanic soundscapes and their human disruption. The paper details an artistic artefact - DIS_turbation - and its integrative approach, by exploring the vibrational and particle-motion component of ocean sound. The methods include place attachment, creative development, nature-connectedness and ecology of Æffect. The novelty lies in addressing biological processes as a creative resource to intervene in underwater noise dialogue, reveal hidden qualities of vibroacoustic ecology, develop artistic artefacts to translate particle-motion in a more grasping way, and foster inclusion with nature.

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. [ABSTRACT FROM AUTHOR]

Acoustic courtship displays are ubiquitous among animals. Signallers use these acoustics to advertise their willingness to mate, while receivers may be able to infer something of the signaller's quality from them. However, increases in anthropogenic noise may reduce the production, transmission and reception of these signals, leading to consequences for reproductive success. In this study, we conducted behavioural observations of courtship interactions of the Mediterranean field cricket, Gryllus bimaculatus , under anthropogenic noise conditions. We found that the presence of traffic noise had no effect on the outcome courtship interactions in this species, and their behaviour during courtship did not appear to be altered either. However, we found that the presence of white noise led to a reduction in male signal production, resulting in fewer successful matings. Males that did signal under white noise conditions had altered signal characteristics, including increased song frequency and reduced tick rate. Mate-guarding behaviour was also found to differ between individuals that courted and those that did not. The use of typical anthropogenic noise and white noise in this experiment allows us to consider the importance of specific characteristics of the acoustic pollutant in causing this disruption. • Human-generated acoustics can have a significant impact on the behaviour of animals. • We observed the courtship of field crickets under anthropogenic noise conditions. • Traffic noise did not affect the mating behaviour or acoustics of these crickets. • White noise affected male signalling behaviour, but not female response behaviour. [ABSTRACT FROM AUTHOR]

Noise pollution is an underappreciated component of global environmental change and can impact species that have a strong reliance on acoustic communication. In urban areas, traffic noise can interfere with the ability of animals to communicate and complete essential aspects of their daily lives. We investigated the impact of traffic noise on the calling behaviour of the brown tree frog (Litoria ewingii) in south‐eastern Melbourne, the fastest‐growing human population centre in Australia. We placed six acoustic recorders at increasing distances from a busy suburban road and recorded the calling behaviour (call pitch and call rate) of brown tree frogs immediately before and after loud traffic noises, and in response to different chorus sizes. Traffic noise resulted in a significant, but short‐term, increase in call pitch in the brown tree frog. Both call pitch and call rate decreased with increasing distance from the road, yet traffic noise still resulted in increased call pitch even 200–300 m from the road. Conversely, although traffic noise increased call pitch across all chorus sizes of the brown tree frog, larger chorus sizes were associated with decreased call pitch. Our study highlights the pervasive, and sustained, impact that anthropogenic noise can have on urban frog populations. [ABSTRACT FROM AUTHOR]

Anthropogenic noise and artificial light at night (ALAN) can disrupt the morning singing routines of urban birds, however, its influence on tropical species remains poorly explored. Here, I assessed the association between light and noise pollution with the dawn chorus onset of the Saffron Finch (Sicalis flaveola) in a city in Colombia. I studied 32 sites comprised of different conditions of urban development based on built cover. I recorded the time of the first song of the Saffron Finch, the conspecific density and measured anthropogenic noise and ALAN using smartphone apps. The findings of this study show that Saffron Finches living in highly developed sites sang earlier at dawn than those occupying less urbanized sites. Unexpectedly, this timing difference was related to ALAN instead of anthropogenic noise, suggesting that light pollution could drive earlier dawn chorus in a tropical urban bird. Saffron Finches could take advantage of earlier singing for signaling territorial ownership among neighbors. Future studies need to assess the influence of ALAN on the dawn chorus timing of Neotropical urban birds.

Most marine mammal- strandings coincident with naval sonar exercises have involved Cuviers beaked whales (Ziphius cavirostris). We recorded animal movement and acoustic data on two tagged Ziphius and obtained the first direct measurements of behavioural responses of this species to mid-frequency active (MFA) sonar signals. Each recording included a 30-min playback (one 1.6-s simulated MFA sonar signal repeated every 25 s); one whale was also incidentally exposed to MFA sonar from distant naval exercises. Whales responded strongly to playbacks at low received levels (RLs; 89-127 dB re 1 µPa): after ceasing normal fluking and echolocation, they swam rapidly, silently away, extending both dive duration and subsequent non-foraging interval. Distant sonar exercises (78-106 dB re 1 µPa) did not elicit such responses, suggesting that context may moderate reactions. The observed responses to playback occurred at RLs well below current regulatory thresholds; equivalent responses to operational sonars could elevate stranding risk and reduce foraging efficiency.

Susceptibility to temporary hearing threshold shift (TTS) in harbor porpoises (Phocoena phocoena) depends on the frequency of the fatiguing sound causing the shift. This study is part of a larger project in which TTS in harbor porpoises was tested after exposure to fatiguing sounds within the 0.5 to 88.4 kHz frequency range. Herein, we report on the TTS induced and hearing recovery in a female harbor porpoise after exposure to 1, 2, and 4 h of continuous one-sixth-octave noise band centered at 0.5 kHz, which is within the frequency range of many high-amplitude anthropogenic sounds. This fatiguing sound was emitted at an average received sound pressure level of 163 dB re 1 µPa, resulting in sound exposure levels (SELs) of 199 to 206 dB re 1 µPa2s. Hearing thresholds for 0.5, 0.71, and 1 kHz tonal signals were determined before and after exposure. Control sessions were used as a baseline and to determine which SELs resulted in statistically significant TTS in the first 4 min after the fatiguing sound stopped (TTS1-4). At 0.5 kHz, the lowest SEL that resulted in significant TTS1-4 (4.3 dB) was 202 dB re 1 µPa2s. At 0.71 and 1 kHz, the lowest SEL that resulted in significant TTS1-4 (5.8 dB and 3.8 dB, respectively) was 205 dB re 1 µPa2s. Hearing always recovered within 60 min after the fatiguing sound stopped. Within the SEL range that was tested, the greatest mean TTS1-4 (7.6 dB) occurred at 0.5 kHz, the center frequency of the fatiguing sound, after exposure to an SEL of 205 dB re 1 µPa2s (4-h exposure); 0.5 kHz is close to the lower bound of porpoise hearing, and ecological impacts of reduced hearing at this frequency are unclear. Results will be used in a future study of this series to generate an auditory weighting curve and to enhance regulatory protection of the harbor porpoise. [ABSTRACT FROM AUTHOR]

Novel anthropogenic noise has received considerable attention in behavioural ecology, but the natural acoustic environment has largely been ignored as a niche axis.Using arrays of speakers, we experimentally broadcasted whitewater river noise continuously for three summers, and monitored spider abundance and behaviour across 15 sites, to test our hypothesis that river noise is an important structuring force as a niche axis.We find substantial evidence that orb‐weaving spiders (Araneidae and Tetragnathidae) are more abundant in high sound level environments, but are not affected by background noise spectrum.We explore multiple possible mechanisms underlying these patterns, such as loss of vertebrate predators and increased prey capture, and assess spider web‐building behaviour and body condition in noise. Continued research on the natural and anthropogenic acoustic environment will likely reveal a web of connections hidden within this neglected ecological niche axis. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Anthropogenic noise has increased underwater ambient sound levels in the range in which most fishes detect and produce acoustic signals. Although the impacts of increased background noise on fish development have been studied in a variety of species, there is a paucity of information on how noise affects parental care. Mouthbrooding is an energetically costly form of parental care in which the brooding fish carries developing larvae in the buccal cavity for the duration of development. In the African cichlid Astatotilapia burtoni, females carry their brood for ~2 weeks during which time they do not eat. To test the hypothesis that increased background noise impacts maternal care behaviors and brood development, we exposed brooding females to a 3‐h period of excess noise (~140 dB) played through an underwater speaker. Over half of noise‐exposed brooding females cannibalized or pre‐maturely released their brood, but 90% of control females exhibited normal brooding behaviors. RNA‐seq analysis revealed that transcripts related to feeding and parental care were differentially expressed in the brains of noise‐exposed females. Juveniles that were exposed to noise during their brood period within the mother's mouth had lower body condition factors, higher mortality and altered head transcriptomes compared with control broods. Furthermore, onset of adult‐typical coloration and behaviors was delayed compared with control fish. Together, these data indicate that noise has severe impacts on reproductive fitness in mouthbrooding females. Our results, combined with past studies, indicate that parental care stages are extremely susceptible to noise‐induced perturbations with detrimental effects on species persistence. [ABSTRACT FROM AUTHOR]