Birdsong Research Articles

The influence of visual and auditory environments in parks on visitors’ landscape preference, emotional state, and perceived restorativeness

Various auditory and visual factors influence people’s perception and restoration experiences in the spatial environments. However, few studies have treated these factors as a comprehensive system phenomenon to reveal their integrated effects. Therefore, a specific explanation of the primary pathways and factors that contribute to the main effects of park soundscapes and visual features and the resulting perceived restorativeness remains unclear. The study surveyed 861 visitors in five urban parks in China and collected audiovisual information. Using Partial Least Squares Structural Equation Modeling (PLS-SEM), the research explored the direct, indirect, and moderating effects of common audiovisual environments in parks on perceived restorativeness, emotional states, and preferences. The results indicate that most natural-related visual and auditory factors provide direct benefits for people’s perceived restorativeness, emotional state, and preference. Additionally, certain landscape features and types of sound sources, such as trees and water sounds, have indirect effects on activating restoration through preference and emotion mediation. The study also reveals the moderating effects of landscape features and sound source types on emotional and perceived restorativeness. Another noteworthy finding is the significant relationship between bird songs and the positive impact on perceived restorativeness, emotional state, and preference, which is closely related to acoustic quality indicators. These findings offer new insights for creating urban park spaces through visual and auditory interactions.

Investigation of Bird Sound Transformer Modeling and Recognition

Birds play a pivotal role in ecosystem and biodiversity research, and accurate bird identification contributes to the monitoring of biodiversity, understanding of ecosystem functionality, and development of effective conservation strategies. Current methods for bird sound recognition often involve processing bird songs into various acoustic features or fusion features for identification, which can result in information loss and complicate the recognition process. At the same time, the recognition method based on raw bird audio has not received widespread attention. Therefore, this study proposes a bird sound recognition method that utilizes multiple one-dimensional convolutional neural networks to directly learn feature representations from raw audio data, simplifying the feature extraction process. We also apply positional embedding convolution and multiple Transformer modules to enhance feature processing and improve accuracy. Additionally, we introduce a trainable weight array to control the importance of each Transformer module for better generalization of the model. Experimental results demonstrate our model’s effectiveness, with an accuracy rate of 99.58% for the public dataset Birds_data, as well as 98.77% for the Birdsonund1 dataset, and 99.03% for the UrbanSound8K environment sound dataset.

Restorative benefits of soundscapes for individuals with psychological disorders

Mental health is a significant focus in the global public health domain today. Soundscapes have been identified as having positive environmental restorative benefits, yet the discussion on the mechanisms through which soundscapes contribute to the recovery from psychological disorders remains insufficiently explored. To guide the creation of restorative soundscapes in psychotherapy settings, this article adopted an "exposure-response" research paradigm. Through a soundscape intervention experiment involving 98 participants, it analyzed the perceived restorativeness evaluations and both physiological and psychological responses of populations with different psychological states. Overall, this article explored the restorativeness of soundscapes for individuals with psychological disorders in a solitary listening condition, with specific soundscapes such as rain sounds, bird songs, and river sounds demonstrating restorative effects. Individuals with psychological disorders rated rain sounds highest, while psychologically healthy individuals gave the highest ratings to bird songs.

Broiler chicken vocalization analysis during a medium-scale heat stress experiment

The poultry industry in Flanders, Belgium, is characterized by highly efficient production mechanisms. To improve awareness for animal health and welfare, the use of neural network-based broiler vocalization detectors has been recently proposed in scientific literature. However, these tools have not yet been tested when used continuously in large-scale deployments. This paper describes the deployment of the broiler vocalization detector to analyze the sonic environment during four experimental rounds, each containing 560 broilers, in a medium scale housing at ILVO, Belgium. Half the broilers were subjected to periods of heat stress (ambient temperature increased to 32°C for 6h/day for 10 days during the last weeks of their lives) and the effect on the diurnal broiler vocalization pattern and occurrence of warbles, pleasure notes, short beeps and distress calls is discussed. While these four different types of vocalizations are common vocalizations in young birds, new types of vocalizations are emerging at an older age. A clustering has been performed to further analyze these new types of vocalizations occurring.

Frequency-dependence may moderate fitness costs linked to reduced bird song complexity.

Animal cultures can undergo rapid changes associated with innovations, revolutions or population decline. Where a rapid shift results in reduced complexity of cultural behaviours, it may have fitness consequences for individuals. Here, we report a dramatic shift in the dominant song type of critically endangered wild regent honeyeaters Anthochaera phrygia. Between 2015 and 2019, most males in the Blue Mountains sang a typical regent honeyeater song (typical Blue Mountains song), but 5%-10% sang an abbreviated version of the song with half the number of syllables (the clipped Blue Mountains song), which was associated with lower pairing success. Since 2020, the proportion of males singing the clipped Blue Mountains song has increased to 50%-75% each year. The likelihood of successful pairing in these males showed a significant concomitant increase, suggesting that the fitness costs associated with the abbreviated song decreased as it became the dominant song type. Our results suggest that the fitness consequences of loss of song complexity in declining and fragmented populations may be ameliorated by frequency-dependent shifts in song type preference.

Social and auditory experience shapes forebrain responsiveness in zebra finches before the sensitive period of vocal learning.

Early-life experiences with signals used in communication are instrumental in shaping an animal's social interactions. In songbirds, which use vocalizations for guiding social interactions and mate choice, recent studies show that sensory effects on development occur earlier than previously expected, even in embryos and nestlings. Here, we explore the neural dynamics underlying experience-dependent song categorization in young birds prior to the traditionally studied sensitive period of vocal learning that begins around 3 weeks post-hatch. We raised zebra finches either with their biological parents, cross-fostered by Bengalese finches beginning at embryonic day 9, or by only the non-singing mother from 2 days post-hatch. Then, 1-5 days after fledging, we conducted behavioral experiments and extracellular recordings in the auditory forebrain to test responses to zebra finch and Bengalese finch songs. Auditory forebrain neurons in cross-fostered and isolate birds showed increases in firing rate and decreases in responsiveness and selectivity. In cross-fostered birds, decreases in responsiveness and selectivity relative to white noise were specific to conspecific song stimuli, which paralleled behavioral attentiveness to conspecific songs in those same birds. This study shows that auditory and social experience can already impact song 'type' processing in the brains of nestlings, and that brain changes at this age can portend the effects of natal experience in adults.

Examining the audiovisual therapy effects on hospital groups of varying linear canopy landscapes and those with hydrodynamic forces.

Recent research has highlighted the beneficial effects of urban green spaces on physical and mental health. This study focused on the hospital population and innovatively subdivided the population into four groups: doctors, caregivers, patients and nurses. A total of 96 volunteers participated in this virtual reality experiment to assess the restoration of a linear canopy landscape and a landscape with different levels of hydrodynamics through interactive audiovisual immersion. We utilized pre-research method, brainwave monitoring technique, psychological scales, observation and interviews in this experiment. The research identified five key findings. First, both linear canopy landscapes and those with low to medium hydrodynamic forces significantly enhance physiological and psychological restoration for all groups, with the most substantial physiological benefits observed in doctors and patients, and the greatest psychological relief noted in caregivers. Second, landscapes with medium hydrodynamic forces yield higher restorative effects than those with low forces in hospital settings. Third, green landscapes with medium and low-density canopies prove more conducive to patient recovery compared to those with high-density canopies. Fourth, the inclusion of bird songs does not markedly affect physiological restoration across the hospital groups. Finally, landscapes that incorporate elements of water dynamics, open skies, and lightly foliated canopies draw significant interest from all groups involved. This study advocates for the integration of natural blue and green elements into hospital environments as complementary therapeutic interventions, aiming to alleviate stress and promote health recovery among hospital communities.

Comparisons of acoustic structures between sexes in a duetting, montane bird

Female song in birds is more widespread than previously thought, and studies across different species are critical for better understanding the entire evolutionary process of bird song. In this study, we recorded the songs of males and females in a duetting, montane bird species, the Elliot's laughingthrush Trochalopteron elliotii, across consecutive breeding seasons. We specifically focused on identifying the number and structure of different song types by males and females, and compared these acoustic structures between the sexes. Our findings revealed that both males and females sang sex‐specific solos. More specifically, females sang a single type of solo that varied significantly in the number of notes, whereas males produced three different solos composed of 2, 3, or 4 notes, respectively. Female solos exhibited significantly more notes and longer song duration compared to males. Male solos typically had a significantly higher maximum frequency for the entire song. No significant differences were observed in the duration of the first note, song rate, and other frequency characteristics between male and female solos. Furthermore, paired males and females coordinated their sex‐specific solos to form duets when challenged by conspecific territory intruders, both within and outside the breeding season. Sex‐specific solos suggested that male and female songs play different roles and may be subject to different selective pressures. Further research is necessary for elucidating the functions of male song, female song, and duets in this montane bird species.

Song determined by phylogeny and body mass in two differently constrained groups of birds: manakins and cardinals

The songs of birds are complex signals that may have several functions and vary widely among species. Different ecological, behavioural and morphological factors, as well as phylogeny, have been associated as predictors of the evolution of song structure. However, the importance of differences in development, despite their relevance, has seldom been considered. Here, we analysed the evolution of song in two families of songbirds that differ in song development, manakins (suboscines) and cardinals (oscines), with their phylogeny, morphology, and ecology. Our results show that song characteristics had higher phylogenetic signal in cardinals than in manakins, suggesting higher evolutionary lability in the suboscines. Body mass was the main predictor of song parameters in manakins, and together with habitat type, had a major effect on cardinals’ song structure. Precipitation and altitude were also associated with some song characteristics in cardinals. Our results bring unexpected insights into birdsong evolution, in which non-learners (manakins) revealed greater evolutionary lability than song learners (cardinals).

Bird song comparison using deep learning trained from avian perceptual judgments.

Our understanding of bird song, a model system for animal communication and the neurobiology of learning, depends critically on making reliable, validated comparisons between the complex multidimensional syllables that are used in songs. However, most assessments of song similarity are based on human inspection of spectrograms, or computational methods developed from human intuitions. Using a novel automated operant conditioning system, we collected a large corpus of zebra finches' (Taeniopygia guttata) decisions about song syllable similarity. We use this dataset to compare and externally validate similarity algorithms in widely-used publicly available software (Raven, Sound Analysis Pro, Luscinia). Although these methods all perform better than chance, they do not closely emulate the avian assessments. We then introduce a novel deep learning method that can produce perceptual similarity judgements trained on such avian decisions. We find that this new method outperforms the established methods in accuracy and more closely approaches the avian assessments. Inconsistent (hence ambiguous) decisions are a common occurrence in animal behavioural data; we show that a modification of the deep learning training that accommodates these leads to the strongest performance. We argue this approach is the best way to validate methods to compare song similarity, that our dataset can be used to validate novel methods, and that the general approach can easily be extended to other species.

Adult neurogenesis is necessary for functional regeneration of a forebrain neural circuit

In adult songbirds, new neurons are born in large numbers in the proliferative ventricular zone in the telencephalon and migrate to the adjacent song control region HVC (acronym used as proper name) [A. Reiner et al., J. Comp. Neurol. 473, 377-414 (2004)]. Many of these new neurons send long axonal projections to the robust nucleus of the arcopallium (RA). The HVC-RA circuit is essential for producing stereotyped learned song. The function of adult neurogenesis in this circuit has not been clear. A previous study suggested that it is important for the production of well-structured songs [R. E. Cohen, M. Macedo-Lima, K. E. Miller, E. A. Brenowitz, J. Neurosci. 36, 8947-8956 (2016)]. We tested this hypothesis by infusing the neuroblast migration inhibitor cyclopamine into HVC of male Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) to block seasonal regeneration of the HVC-RA circuit. Decreasing the number of new neurons in HVC prevented both the increase in spontaneous electrical activity of RA neurons and the improved structure of songs that would normally occur as sparrows enter breeding condition. These results show that the incorporation of new neurons into the adult HVC is necessary for the recovery of both electrical activity and song behavior in breeding birds and demonstrate the value of the bird song system as a model for investigating adult neurogenesis at the level of long projection neural circuits.

Orchard bird song recognition based on multi-view multi-level contrastive learning

In the harvest season, orchards are frequently plagued by birds, and thus significant fruit pecking can adversely affect both the fruit quality and yield. Recognizing bird songs is crucial for preventing damage caused by orchard birds because it can provide the basis for subsequent bird repellent efforts. However, the extensive effort required to annotate sound samples poses a significant challenge for supervised deep learning. In this paper, we propose a self-supervised multi-view learning framework based on multi-level contrasting (MV-MLC) for bird song recognition, which utilizes both time and spectrogram views as inputs. This framework leverages MLC to automatically learn representations from unlabeled data and a multi-scale feature extraction (MSFE) backbone network is employed to capture the temporal features of bird songs at different scales. The time-spectrogram consistency task in MLC learning facilitates semantic-level information exchange across multi-views, while the hierarchical contrastive learning task captures granularity-level information, thereby resulting in more robust contextual representations. In addition, embedding the shuffle attention module in MSFE facilitates mining of the spatial and channel dependencies of bird song features to further enhance the representation of features by the multi-scale network. We conducted extensive experiments using our self-built 10-class bird song data set (Orchard-birds) and the publicly available Birdsdata and Powdermill data sets. The experimental results demonstrated that MV-MLC performed better than state-of-the-art self-supervised models. In particular, MV-MLC obtained outstanding performance even with a small proportion of labeled data. The recognition accuracies based on the Orchard-birds and Birdsdata data sets were 99.40% and 92.67%, respectively, with macro F1-scores of 99.40% and 92.61%.

Phonation threshold pressure in inspiratory vs expiratory phonation

Inspiratory or reverse phonation refers to the production of voice when air is inhaled from the mouth and nostrils into the lungs. This way of phonation occurs naturally during laughter, sighs, and crying [1]. It has also been used to achieve special vocal effects by singers, shamans, and ventriloquists, and is common in the vocalizations of other mammals and birds. Furthermore, it is a useful treatment exercise in voice therapy for several voice disorders [2]. However, despite its relevance, few physical studies of inspiratory phonation have been conducted, and its underlying physics still needs further clarification.

Song and genetic divergence within a subspecies of white-crowned sparrow (Zonotrichia leucophrys nuttalli).

Animal culture evolves alongside genomes, and the two modes of inheritance-culture and genes-interact in myriad ways. For example, stable geographic variation in culture can act as a reproductive barrier, thereby facilitating genetic divergence between "cultural populations." White-crowned sparrows (Zonotrichia leucophrys) are a well-established model species for bird song learning and cultural evolution, as they have distinct, geographically discrete, and culturally transmitted song types (i.e., song dialects). In this study, we tested the hypothesis that divergence between culturally transmitted songs drives genetic divergence within Nuttall's white-crowned sparrows (Z. l. nuttalli). In accordance with sexual selection theory, we hypothesized that cultural divergence between mating signals both preceded and generated genetic divergence. We characterized the population structure and song variation in the subspecies and found two genetically differentiated populations whose boundary coincides with a major song boundary at Monterey Bay, California. We then conducted a song playback experiment that demonstrated males discriminate between songs based on their degree of divergence from their local dialect. These results support the idea that discrimination against non-local songs is driving genetic divergence between the northern and southern populations. Altogether, this study provides evidence that culturally transmitted bird songs can act as the foundation for speciation by sexual selection.

Anthropogenic city noise affects the vocalizations of key forest birds

Anthropogenic city noise affects the vocalizations of key forest birds

Redistribution of songbirds within a migratory stopover site as a response to sylviid warbler song playback

Assessing habitat quality is critical for migrating birds, with implications for fuel loading, predation risk and timing of departure. To efficiently distribute within stopover sites, migrants rely on various cues that facilitate habitat quality assessment. In this study, we conducted a playback experiment at a mid‐route stopover site to test the effects of vocal cues, specifically bird songs, on habitat redistribution during spring migration. To estimate the effect of bird songs on bird abundance we mist‐netted and ringed birds for 60 days on alternating playback treatment (playing songs of three sylviid warbler species) and no playback (control) days. A nearby site was used to control for fluctuations caused by migration waves. Overall, total bird abundance was significantly increased by the playback treatment. This increase resulted from the attraction of conspecifics (species whose songs were played) rather than of other species – sylviids or others. Correspondingly, species richness was seemingly unaffected. To investigate the relationship between internal‐state factors and the attraction to playback in the most abundantly attracted species, Eurasian Blackcap Sylvia atricapilla, we tested associations with age, sex and body condition index but found no significant effects, possibly because of the limited sample size. Our findings challenge established ideas regarding heterospecific attraction and contradict previous studies. Attraction to bird song is discussed in the context of geographical location, timing and internal drivers. Vocal cues, specifically bird songs, may affect micro‐habitat selection by migrating songbirds during stopovers. Consequently, we call for consideration of the influence of the acoustic environment on birds during migratory stopover in future studies, habitat management and conservation efforts.

The Impact of Music on Orchid plants Growth in Polyhouse Environments

Nature and music, two seemingly disparate elements of human experience, are deeply interconnected in ways that resonate across cultures and time. Both evoke emotions, stir the soul, and inspire creativity, offering profound insights into the human condition and our relationship with the world around us. In essence, nature and music are two expressions of the same universal impulse—the longing to connect with something greater than ourselves, to find beauty and meaning in the world around us. Whether we're listening to the songs of birds at dawn or the symphonies of Beethoven, we are reminded of our place in the vast tapestry of creation, where every note, every sound, is a testament to the wonder and mystery of existence. By carefully considering the environmental factors and designing experiments that account for them, researchers can gain a better understanding of how music influences plant growth and optimize its use in agricultural and horticultural practices. This research paper investigates the potential effects of music on orchid growth within polyhouse environments. Orchids are renowned for their delicate beauty and are cultivated worldwide, often in controlled environments like polyhouses. While studies have explored the influence of various environmental factors on orchid growth, the impact of music remains relatively unexplored. This study aims to fill this gap by examining how exposure to music may affect the growth, development, and overall health of orchids in polyhouse conditions. The research employs a combination of experimental methods, including controlled trials, measurements of plant growth parameters, and analysis of physiological indicators. Additionally, the study considers factors such as the type of music, frequency, volume, and duration of exposure. The findings of this research contribute to our understanding of the complex relationship between plants and their acoustic environment, with potential implications for optimizing orchid cultivation practices in polyhouse settings.

Zebra finch song parameters are affected by the breeding status of the male, but not temperature variability

Bird song is a crucial feature for mate choice and reproduction. Song can potentially communicate information related to the quality of the mate, through song complexity, structure or finer changes in syllable characteristics. It has been shown in zebra finches that those characteristics can be affected by various factors including motivation, hormone levels or extreme temperature. However, although the literature on zebra finch song is substantial, some factors have been neglected. In this paper, we recorded male zebra finches in two breeding contexts (before and after pairing) and in two ambient temperature conditions (stable and variable) to see how those factors could influence song production. We found strong differences between the two breeding contexts: compared to their song before pairing, males that were paired had lower song rate, syllable consistency, frequency and entropy, while surprisingly the amplitude of their syllables increased. Temperature variability had an impact on the extent of these differences, but did not directly affect the song parameters that we measured. Our results describe for the first time how breeding status and temperature variability can affect zebra finch song, and give some new insights into the subtleties of the acoustic communication of this model species.

Vocal Repertoire of Chimango Caracaras in Rural and Urban Habitats

ABSTRACT Acoustic communication, such as bird song, is vital in animal ecology, facilitating reproduction, feeding, defense, and more. Variation in bird song may result from adaptation to environmental features such as anthropogenic noise. The vocal repertoire of raptors is essentially unstudied, particularly in urban environments. The aim of this work was to describe and quantify the acoustic repertoire of Chimango Caracaras (Milvago chimango) in rural and urban areas in La Pampa Province, Argentina. I recorded 26 1-min sound samples at each of four breeding colonies (one rural and three urban) during the austral reproductive season of 2021–2022. I recorded 241 vocalizations corresponding to nine clearly distinct call types. Two types of calls made up 50.6% and 19.5% of the vocalizations and seven others made up <10.0% each. Three call types had trills (fast repetitive notes). Average percentage of call types differed significantly between the two habitats (P < 0.01), with more trills produced in rural habitats. Average calling rate was 6.6 ± 5.1 calls/min at rural colonies and 10.7 ± 10.7 at urban colonies. The number of different call types produced was 2.1 ± 1.6 types/min at rural colonies and 2.7 ± 1.8 at urban colonies. The greater calling rate of Chimango Caracaras in urban areas may represent an attempt to improve signal effectiveness among the anthropogenic acoustic clutter.

Experimentally elevated corticosterone increases song output and complexity in common mynas.

Vocalization is an important communication tool that can reflect many aspects of an individual's internal and external condition. This is especially true for birds. Previous research has shown that bird calls and songs change in response to a variety of potential stressors, although the extent and direction of the changes depend on the nature of the stressor and the environment. Circulating glucocorticoids, such as corticosterone, often increase in response to stressors and mediate some of the observed changes via alterations of the individual's physiological state. Acute elevations of corticosterone often occur as a physiological response to short-term stressors; however, the effects of this elevation on adult vocalizations have not been well documented. Here, we experimentally elevated corticosterone at two different levels using a noninvasive method and examined the effects on the vocal communication of male and female adult common mynas (Acridotheres tristis). Corticosterone elevation temporarily increased song output and some measures of song complexity, while call output decreased. These effects were dosage dependent (higher corticosterone levels had a stronger effect), most evident 40 min after ingestion, and some vocal changes were sex-specific. Future studies should investigate whether the changes in vocal performance due to elevated glucocorticoids have consequences for the birds' behavior, reproductive success, and survival.