Vocal Repertoire Research Articles

Notes from (art) Song Lab: A Generative Model for Song Collaborations

Abstract: Song collaborations are a mainstay for pianists who work in vocal repertoire. Those experiences are foundational for exploring singer-pianist relationships, but they rarely address the relationships with composers or text authors. There are few reference materials for composer-performer collaborations, and none that document the triangular connections between composers, poets, and performers. In June 2024, (art) Song Lab celebrated its thirteenth year of fostering these collaborations. This column explores the how and why of these creative combinations, with analysis of new approaches to productive communication, augmented musicianship, and healthy respect for the creative integrity among all participants.

Field tests reveal acoustic variation of call types in a subterranean rodent, the Northern Mole Vole Ellobius talpinus

Abstract This study investigates acoustic variation of human-audible sonic (below 20 kHz) and human-inaudible ultrasonic (above 20 kHz) calls in a wild subterranean rodent, the Northern Mole Vole (Ellobius talpinus), under 3 call-eliciting tests conducted during captures for 1 day. The Contact-in-Tunnel Test modeled contacts of 2 individuals during digging earth in a burrow tunnel. The Restraint Test modeled restraint of an animal by a surrogate predator (human hand). The Release-to-Burrow Test modeled acoustic communication of many family members returned to their home burrow after their isolation for about 8 h, from morning to evening. We described 8 call types: 3 sonic, 3 ultrasonic, and 2 expanding from sonic to ultrasonic range of frequencies; 6 call types were described for the first time for this species. No relationship was found between acoustic parameters and proxies of body size (body mass and the width of 2 upper incisors). No sex differences were found in body size or the acoustic parameters. Different call types prevailed in different tests: wheeks and upsweeps were made during peaceful interactions; squeaks and squeals were related to animal discomfort during the Restraint Test; rasps were only made in Release-to-Burrow Tests when animals were plugging the burrow entrance; and variative calls did not show any relationship with type of test. Based on presence or absence of certain call types in the tests, we evaluate their potential communicative role in comparison with published data on vocal repertoires of other subterranean rodents.

Unsupervised discovery of family specific vocal usage in the Mongolian gerbil.

In nature, animal vocalizations can provide crucial information about identity, including kinship and hierarchy. However, lab-based vocal behavior is typically studied during brief interactions between animals with no prior social relationship, and under environmental conditions with limited ethological relevance. Here, we address this gap by establishing long-term acoustic recordings from Mongolian gerbil families, a core social group that uses an array of sonic and ultrasonic vocalizations. Three separate gerbil families were transferred to an enlarged environment and continuous 20-day audio recordings were obtained. Using a variational autoencoder (VAE) to quantify 583,237 vocalizations, we show that gerbils exhibit a more elaborate vocal repertoire than has been previously reported and that vocal repertoire usage differs significantly by family. By performing gaussian mixture model clustering on the VAE latent space, we show that families preferentially use characteristic sets of vocal clusters and that these usage preferences remain stable over weeks. Furthermore, gerbils displayed family-specific transitions between vocal clusters. Since gerbils live naturally as extended families in complex underground burrows that are adjacent to other families, these results suggest the presence of a vocal dialect which could be exploited by animals to represent kinship. These findings position the Mongolian gerbil as a compelling animal model to study the neural basis of vocal communication and demonstrates the potential for using unsupervised machine learning with uninterrupted acoustic recordings to gain insights into naturalistic animal behavior.

“To Help the Singer”: Recognizing the Scholarship of Martha Gerhart

Abstract: Pianist Martha Gerhart’s long career has been dedicated to the preparation and performance of classical vocal repertoire. Her work, part of professional operatic productions for decades, has also resulted in dozens of printed resources, many of which are used by nearly every singer, voice teacher and coach in North America. Among many other scholarly credits, she is the translator for the Hal Leonard aria anthology series: through this alone, Gerhart’s work has impacted thousands of people. This article aims to foster recognition of the many contributions of this unsung hero in the classical vocal world.

Humans need auditory experience to produce typical volitional nonverbal vocalizations

Human nonverbal vocalizations such as screams and cries often reflect their evolved functions. Although the universality of these putatively primordial vocal signals and their phylogenetic roots in animal calls suggest a strong reflexive foundation, many of the emotional vocalizations that we humans produce are under our voluntary control. This suggests that, like speech, volitional vocalizations may require auditory input to develop typically. Here, we acoustically analyzed hundreds of volitional vocalizations produced by profoundly deaf adults and typically-hearing controls. We show that deaf adults produce unconventional and homogenous vocalizations of aggression and pain that are unusually high-pitched, unarticulated, and with extremely few harsh-sounding nonlinear phenomena compared to controls. In contrast, fear vocalizations of deaf adults are relatively acoustically typical. In four lab experiments involving a range of perception tasks with 444 participants, listeners were less accurate in identifying the intended emotions of vocalizations produced by deaf vocalizers than by controls, perceived their vocalizations as less authentic, and reliably detected deafness. Vocalizations of congenitally deaf adults with zero auditory experience were most atypical, suggesting additive effects of auditory deprivation. Vocal learning in humans may thus be required not only for speech, but also to acquire the full repertoire of volitional non-linguistic vocalizations.

“Kyiv – the heart of Ukraine!” by Volodymyr Huba in the context of updating the chamber vocal repertoire

“Kyiv – the heart of Ukraine!” by Volodymyr Huba in the context of updating the chamber vocal repertoire

Enriched social environment affects the utterance of acoustic signals of captive François' langurs

Vocal communication serves as an important mode of interaction among animals. The quantitative analysis of acoustic signals holds scientific value in highlighting the importance of understanding the social-ecological contexts and their effects on acoustic communication. The results can provide a direct scientific guidance for enhancing the welfare and management of captive animals. From January to February 2022 and from December 2022 to February 2023, we conducted a study involving 30 captive François' langurs (Trachypithecus francoisi) housed in nine enclosures. We collected acoustic signals along with their associated social-ecological contexts and recorded the social composition and number of François' langurs in each enclosure. We in total identified 23 call types based on human ear auditory, spectrogram visual inspection, and quantitative analysis of 37 acoustic parameters. Our findings revealed that adult males exhibited nine call types (five adult male-specific types), adult females 11 call types (seven adult female-specific types), juveniles eight call types (two juvenile-specific types), and infants five call types (two infant-specific types). The asymmetry in call types indicated distinct social roles among different sex-age classes of François' langurs. We found that a complex social composition or larger group size resulted in a more diverse range of call types and increased utterance frequency among François' langurs. The increased utterance frequency was linked to calls used in neutral (contact), affiliation, mating, and vigilance contexts, indicating that a diverse social setting encourages social interaction and boosts the occurrence of natural behaviors, and may also result in increased tension and anxiety. Implementing a one-male multi-female model with ample breeding space for captive François' langurs was identified as beneficial for enhancing vocal communication and improving animal welfare. This study established the first vocal repertoire of François' langurs, offering a novel scientific approach to evaluating the welfare of this endangered species through vocal behaviors.

Diversity and plasticity of vocalisations in an elusive and arboreal small mammal: the edible dormouse (Glis glis)

ABSTRACT The acoustics of small mammals, particularly dormice species, are generally understudied. During this study, we explored the vocalisations and acoustic behaviour of the edible dormouse (Glis glis) in various environments in Catalonia using ultrasound recorders. Up to five different types of calls were identified in various environmental conditions (captivity and free-ranging animals) and developmental stages, from pups to adults. Additionally, one new call type was described. Significant differences were observed between captive and wild dormice (e.g. length of the calls and position of the peak harmonic), enhancing the plasticity of their vocalisations. In addition, ultrasonic sound production was discovered in pups, suggesting ontogenetic changes in the vocal repertoire. The lack of differences in vocalisations between sexes reported in captivity highlight the importance of traditional monitoring methods (i.e. nest boxes) for population monitoring in the case of the edible dormouse. The potential of the acoustic method as a non-invasive tool for studying ecological behaviours and interactions, or early detection of the species in the natural environment is emphasised. This study provides an open call reference library, laying the groundwork for a better understanding of edible dormouse acoustics, and focuses on the importance of future research to explore the acoustic social behaviour of the species.

Acoustic behavior of humpback whale calves on the feeding ground: Comparisons across age and implications for vocal development.

Studying sound production at different developmental stages can provide insight into the processes involved in vocal ontogeny. Humpback whales (Megaptera novaeangliae) are a known vocal learning species, but their vocal development is poorly understood. While studies of humpback whale calves in the early stages of their lives on the breeding grounds and migration routes exist, little is known about the behavior of these immature, dependent animals by the time they reach the feeding grounds. In this study, we used data from groups of North Atlantic humpback whales in the Gulf of Maine in which all members were simultaneously carrying acoustic recording tags attached with suction cups. This allowed for assignment of likely caller identity using the relative received levels of calls across tags. We analyzed data from 3 calves and 13 adults. There were high levels of call rate variation among these individuals and the results represent preliminary descriptions of calf behavior. Our analysis suggests that, in contrast to the breeding grounds or on migration, calves are no longer acoustically cryptic by the time they reach their feeding ground. Calves and adults both produce calls in bouts, but there may be some differences in bout parameters like inter-call intervals and bout durations. Calves were able to produce most of the adult vocal repertoire but used different call types in different proportions. Finally, we found evidence of immature call types in calves, akin to protosyllables used in babbling in other mammals, including humans. Overall, the sound production of humpback whale calves on the feeding grounds appears to be already similar to that of adults, but with differences in line with ontogenetic changes observed in other vocal learning species.

Solfeggi as Models for Instruction in Counterpoint and Fugue

This essay makes a contribution to our current understanding of how solfeggi were used in the Neapolitan conservatories in the late eighteenth century. To this end, I investigate how this repertoire was used and applied, both in practice and in written counterpoint. Through documentary evidence derived from student counterpoint notebooks, the ar ticle reveals how themes in solfeggi by well-known masters were reused and adapted in lessons of written counterpoint. These findings suggest that vocal repertoires that were sung in these pedagogical milieus were borrowed by teachers and students through tech niques of transformation and adaptation in order to be reused in new compositions.

Considering Crossover and the Collaborative Pianist

Abstract: The term "crossover" in classical vocal music has generally been used to refer to a classically-oriented artist's forays into non-classical styles or genres. In the singers' world, crossover not only exists, but is increasingly accepted as an important part of the twenty-first century singer's training and preparation. But what of the singer's partner, the pianist and/or coach who will work with them side-by-side? How are pianists and voice coaches affected by the new trends in vocal repertoire? The authors talked with coach-conductors Kathleen Kelly and Stephanie Rhodes Russell about navigating crossover trends as pianists and coaches.

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.

Vocalizations of the Pekin duck (Anas platyrhynchos domesticus): how stimuli, sex, and social groups affect their vocal repertoire

Pekin ducks are exposed to stressors such as heat stress, enteric pathogens, mycotoxins, and other environmental stressors. We know from wild bird literature that birds communicate through vocalizations. We hypothesized that Pekin ducks would have a diverse repertoire that is affected by the sex, social group, and specific stimuli. We utilized adult Pekin ducks to develop a vocal repertoire. We placed 1 to 4 ducks of varying sexes into a sound chamber with various stimuli used to encourage new vocalizations. Birds were recorded for 20 min with several variations of number and sexes of ducks. Once the ducks were recorded each vocalization that was clipped was named based on a predetermined naming system. We characterized the vocal system of the ducks under each stimulus and social treatment in 4 ways: overall call rates, call diversity, call repertoire, and call spectral properties. In all cases, normality of residuals and homogeneity of variances for GLM and ANOVA models were confirmed using Proc Univariate (SAS v9.4) where a p ≤ 0.05 was considered significant. We found that Pekin ducks produce up to 16 different vocalizations. The treatments had a significant effect on the overall rate of calls given by the ducks (ANOVA: F6,31 = 8.55, p < 0.0001). Ducks produced the most calls by far when someone was sitting in the chamber with them (30.04 ± 4.45 calls/min). For call diversity, we found that there was a significant main effect of hen number (F218 = 12.21, p = 0.0004) but no main effect of drake number (F3,18 = 3.04, p = 0.0555). Cluster analyses indicated that certain types of calls were given under specific conditions. There were generally 6 major clusters of vocal repertoires (R-square = 0.899, Cubic Clustering Criterion = 9.30). Our results suggest that Pekin ducks are affected by the types of stimuli and social environment in how much they vocalize and in the properties of the calls they use. In addition, males and females differ somewhat in the repertoire of the calls they use, and in the spectral properties of their calls.

What does the fox say? Arctic fox vocalization and associated den behaviours

Foxes (Vulpes spp.) are small, solitary canids with relatively low social complexity compared to more gregarious canids, such as wolves and dogs. They are, therefore, expected to have a relatively simple vocal repertoire, with limited low-intensity sounds for close communication and many high-intensity sounds for long-distance communication. Arctic foxes (Vulpes lagopus), like many other foxes, are largely solitary outside of the breeding season. However, they have the largest litter size in the order Carnivora and may experience enhanced social complexity during the breeding season. In this study, we document the vocal repertoire of the Arctic fox during the breeding season, and how it changes before and after the emergence of pups. We also describe the relationship between vocalizations and other denning behaviours. Camera-traps captured six distinct sounds produced by breeding pairs of Arctic foxes and their young at dens: territorial barks, warning barks, alarm calls, cooing, whines and growling. Our study shows that although high-intensity sounds, such as territorial barks, are an important form of long-distance communication among Arctic foxes, low-intensity sounds and sound mixing are used on their dens following pup emergence. Thus, Arctic fox vocalization may be more complex than previously documented.

Vocal repertoire of Microhyla nilphamariensis from Delhi and comparison with closely related M. ornata populations from the western coast of India and Sri Lanka.

Advertisement calls in frogs have evolved to be species-specific signals of recognition and are therefore considered an essential component of integrative taxonomic approaches to identify species and delineate their distribution range. The species rich genus Microhyla is a particularly challenging group for species identification, discovery and conservation management due to the small size, conserved morphology and wide distribution of its members, necessitating the need for a thorough description of their vocalization. In this study, we provide quantitative description of the vocal behaviour of Microhyla nilphamariensis, a widely distributed south Asian species, from Delhi, India, based on call recordings of 18 individuals and assessment of 21 call properties. Based on the properties measured acrossed 360 calls, we find that a typical advertisement call of M. nilphamariensis lasts for 393.5± 57.5 ms, has 17 pulses on average and produce pulses at rate of 39 pulses/s. The overall call dominant frequency was found to be 2.8 KHz and the call spectrum consisted of two dominant frequency peaks centered at 1.6 KHz and 3.6 KHz, ranging between 1.5-4.1 KHz. Apart from its typical advertisement call, our study also reveals the presence of three 'rare' call types, previously unreported in this species. We describe variability in call properties and discuss their relation to body size and temperature. We found that overall dominant frequency 1 (spectral property) was found to be correlated with body size, while first pulse period (temporal property) was found to be correlated with temperature. Further, we compare the vocal repertoire of M. nilphamariensis with that of the congener Microhyla ornata from the western coast of India and Sri Lanka and also compare the call properties of these two populations of M. ornata to investigate intra-specific call variation. We find statistically significant differentiation in their acoustic repertoire in both cases. Based on 18 call properties (out of 20), individuals of each locality clearly segregate on PCA factor plane forming separate groups. Discriminant function analysis (DFA) using PCA factors shows 100% classification success with individuals of each locality getting classified to a discrete group. This confirms significant acoustic differentiation between these species as well as between geographically distant conspecifics. The data generated in this study will be useful for comparative bioacoustic analysis of Microhyla species and can be utilized to monitor populations and devise conservation management plan for threatened species in this group.

Ultrasound and ultraviolet: crypsis in gliding mammals.

Gliding is only present in six extant groups of mammals-interestingly, despite divergent evolutionary histories, all mammalian gliders are strictly nocturnal. Gliding mammals also seem to have relatively high rates of ultrasound use and ultraviolet-induced photoluminescence (UVP) in contrast with their close relatives. Therefore, we hypothesized that, despite diverging lineages, gliding mammals use similar modes of cryptic communication compared to their non-gliding counterparts. We developed two datasets containing the vocal range (minimum-maximum of the dominant harmonic; kHz) and UVP of 73 and 82 species, respectively; we report four novel vocal repertoires and 57 novel observations of the presence or absence of UVP. We complemented these datasets with information about body size, diel activity patterns, habitat openness, and sociality to explore possible covariates related to vocal production and UVP. We found that the maximum of the dominant harmonic was significant higher in gliding mammals when vocalizing than their non-gliding relatives. Additionally, we found that nocturnality was the only significant predictor of UVP, consistent with the previous hypothesis that luminophores primarily drive UVP in mammal fur. In contrast, however, we did not find UVP ubiquitous in nocturnal mammals, suggesting that some unknown process may contribute to variation in this trait.

The hidden fitness of the male zebra finch courtship song.

Vocal learning in songbirds is thought to have evolved through sexual selection, with female preference driving males to develop large and varied song repertoires1-3. However, many songbird species learn only a single song in their lifetime4. How sexual selection drives the evolution of single-song repertoires is not known. Here, by applying dimensionality-reduction techniques to the singing behaviour of zebra finches (Taeniopygia guttata), we show that syllable spread in low-dimensional feature space explains how single songs function as honest indicators of fitness. We find that this Gestalt measure of behaviour captures the spectrotemporal distinctiveness of song syllables in zebra finches; that females strongly prefer songs that occupy more latent space; and that matching path lengths in low-dimensional space is difficult for young males. Our findings clarify how simple vocal repertoires may have evolved in songbirds and indicate divergent strategies for how sexual selection can shape vocal learning.

Breeding biology, diet and vocal repertoire of White-rumped Monjita Xolmis velatus

Breeding biology, diet and vocal repertoire of White-rumped Monjita Xolmis velatus

Ontogeny of vocalizations in Adélie penguin (Pygoscelis adeliae) chicks from West Antarctica

Acoustic indices are an efficient method for monitoring dense aggregations of vocal animals but require understanding the acoustic ecology of the species under examination. The present understanding of avian behavior and vocal development is primarily derived from the research of songbirds (Passeriformes). However, given that behavior and environment can differ greatly among bird orders, passerine birdsong may be insufficient to define the vocal ontogeny of non-passerine birds. Like many colonial nesting seabirds, the Adélie penguin (Pygoscelis adeliae) is adapted to loud and congested environments with limited cues to identify kinship within aggregations of conspecifics. In addition to physical or geographical cues to identify offspring, adult P. adeliae rely on vocal modulation. Numerous studies have been conducted on mutual vocal modulations in mature P. adeliae, but limited research has explored the vocal repertoire of the chicks and how their vocalizations evolve over time. Using the deep learning-based system, DeepSqueak, this study characterized the vocal ontogeny of P. adeliae chicks in the West Antarctic Peninsula to aid in autonomously tracking their age. Understanding the phenological communication patterns of vocal-dependent seabirds can help measure the impact of climate change on this indicator species through non-invasive methods.

Contemporary Vocal Repertoire Considerations for the Classical Singer

Abstract: Author Justin John Moniz addresses the exploration of contemporary vocal repertoire for the classical singer. Moniz discusses effective teaching methods rooted in evidence-based practice and advocates for the exploration of student curiosities outside one’s primary area of concentration. Included is a sample list of popular song repertoire for four voice types: soprano, mezzo-soprano, tenor, and baritone. These selections are intended to provide even those most unfamiliar with popular song an opportunity to explore a new style with greater probabilities of ease and coordination.