Vocal Repertoire Research Articles

Male European badger churrs: insights into call function and motivational basis

Determining the contexts of emission and information content of vocal signals can yield insights into the function of different call types, and remains an important step towards understanding the diversification of mammalian vocal repertoires. In this study, we used infra-red video cameras and remote audio recorders to document seasonal and contextual variation in male European badger (Meles meles) churr production over a 24-month period, and acoustic analysis based on source-filter theory to examine whether churr acoustic structure varies according to the caller’s arousal state and identity. Our behavioural observations revealed that male churrs are produced almost exclusively during the breeding season. Further contextual analysis showed that males emit churrs during close-range interactions with female conspecifics, often during copulation attempts, and churr directly into sett entrances. In addition, males involved in close-range social interactions delivered churrs with more call units per second than those vocalising without other conspecifics in close proximity. Discriminant function analysis also revealed that male churrs are individually distinctive, and confirmed that the formants (vocal tract resonances) contribute the most to caller identity. These findings indicate that badger churrs are sexual calls with the potential to signal male arousal state and identity in reproductive contexts. They also add to an increasing body of literature on the importance of formants for identity cueing in nonhuman mammals.

The Amapá treefrog Boana dentei (Bokermann, 1967): diagnosis and redescription (Hylinae: Cophomantini)

ABSTRACT Many aspects of the Amazonian amphibian fauna are yet understudied. This is the case of the Amapá treefrog, Boana dentei, which was described in the 1960s based on a single female specimen from Serra do Navio, a Brazilian region of lowland Amazonian forests in the easternmost portion of the Guiana Shield. The species has been reported only a few times since its description, and phenotypic data from its type locality still remain unknown. We redescribe this treefrog species, including the first characterisation of the male, life colours, tadpole, vocalisation, and notes on habitat, based on a newly collected series from the type locality. Boana dentei is sexually dimorphic with respect to external morphology and colour patterns. Males are distinguished from females by a smaller snout–vent length, lighter dorsal colouration, bright yellow colour in ventral hindlimbs and palm of hand, and enlarged prepollex. Boana dentei is distinguished from other members of the B. albopunctata group by the snout truncate from above and rounded to vertical in profile, calcar absent on heel, black vertical bars on thigh, and vocal repertoire composed of three types of pulsed notes.

Роль песни о войне в формировании музыкально-эстрадного искусства Якутии (1940-1970-е гг.)

The article is devoted to the problem of studying musical variety art of the Sakha Republic (Yakutia). Compositions of the popular song genre and phenomena of the Yakut musical variety art of the 1940-1970s are examined from the viewpoint of representting the theme of the Great Patriotic War. The research material includes war songs of the Yakut professional and amateur composers: M. Zhirkov, Kh. Maksimov, O. Ivanova-Sidorkevich. War songs occupied an important place in the repertoire of variety performers - M. Popova, N. Trapeznikova, Yu. Platonov - thus promoting formation of the musical variety genre. Emphasis is made on previously unpublished scores of popular war songs from the repertoire of the first Yakut pop singers. The analysis of the vocal repertoire of the Yakut pop singers allows concluding that war songs played an essential role in formation of the Yakut musical variety art.

Ultrasonic vocalizations in house mice depend upon genetic relatedness of mating partners and correlate with subsequent reproductive success

BackgroundCourtship vocalizations are used by males of many species to attract and influence the behavior of potential mating partners. Our aim here was to investigate the modulation and reproductive consequences of courtship ultrasonic vocalizations (USVs) in wild-derived house mice (Mus musculus musculus). The courtship USVs of male mice are surprisingly complex and are composed of a variety of different syllable types. Our specific aims were to test whether (1) the emission of courtship USVs depends upon the kinship of a potential mating partner, and (2) whether USV emission during courtship affects the pairs’ subsequent reproductive success.ResultsWe experimentally presented males with an unfamiliar female that was either genetically related or unrelated, and we recorded USV emission, first while the sexes were separated by a perforated partition and then during direct interactions, after removing the partition. USVs were detected by the Automatic Mouse Ultrasound Detector (A-MUD) and manually classified into 15 syllable types. The mice were kept together to test whether and how courtship vocalizations predict their subsequent reproductive success. We found that the mice significantly increased their amount of vocalizations (vocal performance) and number of syllable types (vocal repertoire) after the partition was removed and they began interacting directly. We show that unrelated pairs emitted longer and more complex USVs compared to related pairs during direct interactions. Unrelated pairs also had a greater reproductive success compared to related pairs, and in addition we found a negative correlation between the mean length and amount of vocalizations with the latency to their first litter.ConclusionOur study provides evidence that house mice modulate the emission of courtship USVs depending upon the kinship of potential mating partners, and that courtship USVs correlate with reproductive success.

Vocal Repertoire and Extreme Sexual Size Dimorphism in the Fijian Ground Frog Cornufer vitianus (Anura, Ceratobatrachidae)1

The vocal repertoire of males of Cornufer vitianus from the lowland mangrove forests of Viwa Island, off the coast of Viti Levu, Fiji is described. All calls were placed into two categories: those with a high fundamental frequency, and those with a low fundamental frequency. Within each category, there is relatively high call variation. Individual males are capable of producing both the low- and high-frequency calls; some males produce predominantly the high-frequency call, others are low-frequency callers, and others alternate between the two forms. C. vitianus is among the most sexually size dimorphic amphibians known. Females were conspicuously and significantly larger than males, and we found the ratio of the mean female-to-male snout–vent lengths of 2.22. Extreme sexual size dimorphism (SSD) is a trait rare among anurans as a whole, yet is most often seen among species of the genera Cornufer and Platymantis of the western Pacific. A hypothesis is put forward relating call variability and SSD in C. vitianus.

Classification of Florida manatee (Trichechus manatus latirostris) vocalizations.

The vocal repertoire for the Florida manatee is quantitatively categorized from a sample of 1114 calls recorded from 3 different manatee habitats in Florida. First, manatee vocalizations were categorized into five call categories based on visual inspection of spectrograms and following descriptions provided in previous studies. Second, based on measurements of 17 acoustic parameters, the subjective classification scheme was validated using classification and regression trees (CARTs) and model-based cluster analysis paired with silhouette coefficients. CART analysis revealed that these five broad call categories can be successfully distinguished based on correct classification scores of 41.6%-62.5%. Silhouette coefficients determined that the manatee vocal repertoire is highly intergraded. This study supports and expands upon existing subjective categorization schemes by providing a quantifiable methodology for describing the Florida manatees' vocal repertoire. These findings contribute to the increasing number of studies suggesting many animal species vocal repertoires contain graded call types.

The vocal repertoire of the Cactus Conure Eupsittula cactorum (Aves; Psittaciformes)

Few species of Psittaciformes have the vocal repertoire used to facilitate complex social interactions described. The Cactus Conure (Eupsittula cactorum) is not an exception since it depends on acoustic communication for many aspects of its biology. Here, we describe the vocal repertoire of E. cactorum. The research was undertaken between September 2015 and April 2016 at Quixada (Ceara state, Brazil), where the birds were recorded in the early mornings (05:00–09:00 h) and late afternoons (15:00–18:00 h). During the observations, we recorded the calls and described the behavioral responses to each of these calls. We found nine calls, namely sentinel, flight contact, food appeal, flight call, alarm, alarm II; juvenile alarm, agonistic, congregation. A multinomial regression shows that each of these components is structurally different, and displays enough call differentiation to guarantee efficient communication. The species is especially vocally active when the individuals are in large flocks, but the individuals are discreet and quiet when alone or in pairs. On these behavioral contexts, it was common to observe low-intensity signals, proper for close-range interactions. Overall, E. cactorum shows a complex repertoire, which is somewhat expected for social species.

Untangling cryptic diversity in the High Andes: Revision of the Scytalopus [magellanicus] complex (Rhinocryptidae) in Peru reveals three new species

AbstractTropical mountains feature marked species turnover along elevational gradients and across complex topography, resulting in great concentrations of avian biodiversity. In these landscapes, particularly among morphologically conserved and difficult to observe avian groups, species limits still require clarification. One such lineage is Scytalopus tapaculos, which are among the morphologically most conserved birds. Attention to their distinctive vocal repertoires and phylogenetic relationships has resulted in a proliferation of newly identified species, many of which are restricted range endemics. Here, we present a revised taxonomy and identify species limits among high-elevation populations of Scytalopus tapaculos inhabiting the Peruvian Andes. We employ an integrated framework using a combination of vocal information, mitochondrial DNA sequences, and appearance, gathered from our own fieldwork over the past 40 yr and supplemented with community-shared birdsong archives and museum specimens. We describe 3 new species endemic to Peru. Within all 3 of these species there is genetic differentiation, which in 2 species is mirrored by subtle geographic plumage and vocal variation. In a fourth species, Scytalopus schulenbergi, we document deep genetic divergence and plumage differences despite overall vocal similarity. We further propose that an extralimital taxon, Scytalopus opacus androstictus, be elevated to species rank, based on a diagnostic vocal character. Our results demonstrate that basic exploration and descriptive work using diverse data sources continues to identify new species of birds, particularly in tropical environs.

Vocal repertoires and insights into social structure of sperm whales (Physeter macrocephalus) in Mauritius, southwestern Indian Ocean

AbstractSperm whales communicate using codas (stereotyped click sequences). Females and juveniles live in long‐term social units, and units with similar coda repertoires share vocal clan membership. Vocal clans exhibit culturally defined differences in their multilevel social structure. Here, we aimed to identify different social units among sperm whales in Mauritius in the southwestern Indian Ocean, and to describe and compare their coda repertoires to investigate the presence of different vocal clans. We conducted six boat‐based surveys between 2008 and 2013, during which 101 different individuals were photo‐identified. Analysis of associations between 22 resighted individuals divided them into four candidate social units, but a lack of resightings impedes solid delineation of social units. Based on number and rhythm of clicks, at least 24 discrete coda types were detected among 4,767 analyzed codas using two different classification methods. Comparison of coda repertoires recorded from seven sperm whale groupings revealed the possible existence of two sympatric vocal clans, but the size differences of recorded repertoires warrant caution of interpretation. To further evaluate social structuring and the presence of different vocal clans in this region, future surveys should aim at obtaining long‐term sighting and acoustic data, and cover a more extensive area.

The Antillean manatee produces broadband vocalizations with ultrasonic frequencies

Antillean manatees produce vocalizations reported to be important for communication, but their vocal behavior throughout their geographic range is poorly understood. A SoundTrap recorder (sample rates: 288/576 kHz) was deployed in Belize to record vocalizations of wild manatees in a seagrass channel and of a young rehabilitated and released manatee in a shallow lagoon. Spectral analysis revealed broadband vocalizations with frequencies up to 150 kHz and a high proportion of calls with ultrasonic components. Ultrasonic frequency components appear prevalent in their vocal repertoire and may be important to manatee communication.

Preference for leisure items over edible items in individuals with dementia: A replication.

We replicated previous research in which adults with dementia tended to show a preference for leisure items over edible items when presented in the same array. Additionally, we conducted engagement analyses with the highest, middle, and lowest preference leisure items to determine whether relative preference corresponded to engagement in the natural environment. The most highly preferred stimulus for 6 out of 7 participants was a leisure item, and for each of those six the top 3 preferred stimuli were leisure stimuli. For 4 participants, the most preferred stimulus also produced the longest duration of engagement. We discuss the issues we encountered when conducting preference assessments with adults with intact vocal verbal repertoires, and suggest potential explanations for the displacement of edibles by leisure stimuli in older adults with dementia.

Review of Automatic Detection and Classification Techniques for Cetacean Vocalization

Cetaceans have elicited the attention of researchers in recent decades due to their importance to the ecosystem and their economic values. They use sound for communication, echolocation and other social activities. Their sounds are highly non-stationary, transitory and range from short to long sounds. Passive acoustic monitoring (PAM) is a popular method used for monitoring cetaceans in their ecosystems. The volumes of data accumulated using PAM are usually big, so they are difficult to analyze using manual inspection. Therefore different techniques with mixed outcomes have been developed for the automatic detection and classification of signals of different cetacean species. So far, no single technique developed is perfect to detect and classify the vocalizations of over 82 known species due to variability in time-frequency, difference in the amplitude among species and within species' vocal repertoire, physical environment, among others. The accuracy of any detector or classifier depends on the technique adopted as well as the nature of the signal to be analyzed. In this article, we review the existing techniques for the automatic detection and classification of cetacean vocalizations. We categorize the surveyed techniques, while emphasizing the advantages and disadvantages of these techniques. The article suggests possible research directions that can improve existing detection and classification techniques. In addition, the article recommends other suitable techniques that can be used to analyze non-linear and non-stationary signals such as the cetaceans' signals. Several research have been dedicated to this topic, however, there is no review of these past results that gives a quick overview in the area of cetacean detection and classification. This review will help researchers and practitioners in the field to make insightful decisions based on their requirements.

Analysis of Template-Based Detection Algorithms for Inshore Bryde’s Whale Short Pulse Calls

Marine mammals use sound for communication and echolocation within their ecosystems. The detection of these sounds is an important aspect of signal processing, such that we can estimate the spatial position and direction of arrival of these mammals, and have an understanding of their ecology. Passive acoustic monitoring (PAM) is widely used to understand marine mammal movement and vocal repertoire. In PAM, datasets are accumulated over days, months or years. Thus, it is impracticable to manually analyse the datasets because it is very large. This motivated the development of automated sound detection techniques for marine mammals, which most often varies depending on the vocal duration, frequency range and call type. In this paper, continuous recordings of Bryde's whale (Balaenoptera edeni edeni) short pulse calls (<; 3.1s long) were collected on a weekly basis from December 2018 to April 2019 on sighting of the individual in a single site in the endmost South-West of South Africa. The sound, previously not documented off South Africa, was observed on visual confirmation of the presence of inshore Brydes's whale. In addition, the paper develops and analyses two automated template-based detection algorithms for this short pulse call, employing dynamic time warping (DTW) and linear predictive coding (LPC) techniques. These proposed template-based detectors are novel, as they have not being previously used in Bryde's whale sound detection in the literature. When applied to the continuous recordings of the short pulse calls, the DTW-based and LPC-based detection algorithms obtained a sensitivity of 96.04% and 97.14% respectively for high signal-to-noise ratio (about 10dB above the ambient sound). Otherwise, for low SNR, the DTW-based and LPC-based detection algorithms obtained a sensitivity of 94.98% and 96.00% respectively. These detection algorithms exhibit low computational time complexity and can be modified to analyse the movement of obscure but vocal marine species instead of manual identification.

Professional training of future music art teachers for inclusive education: theoretical and technological aspects

The article is devoted to the actual problem of contemporary art education ἦ#x201C; to improve the professional training of future music art teachers for children’s inclusive education. Its purpose is to present the results of theoretical understanding of the developmental and healing potential of music, to develop technological support in future music art teachers’ professional training for children’s inclusive education. According to the results of the study, the basic concept of the study was defined as: “professional training of future music art teachers for inclusive education”, which is seen as an educational process aimed at ensuring students’ readiness to provide a system of educational services to persons with special educational needs in their future professional activity, and it involves mastering their inclusively oriented musical and pedagogical knowledge, skills and personal qualities. To improve the professional training of future music art teachers for children’s inclusive learning, the findings of the latest research in the field of art and musicpedagogical theory concerning the harmonizing and music-therapeutic influence of music on the personality of a child in need of educational inclusion were used; criteria of musical works selection for children with psycho-physiological disabilities have been identified; there was developed and substantiated developmental and corrective technique of training singing that can be used in inclusive classes of different age, gender and cognitive abilities of children. Developmental and corrective technique of training singing includes innovative content of children’s teaching, comprising a specially selected vocal repertoire; lesson and extracurricular forms of training; specific teaching methods for students with special educational needs.

Lateralized sound production in the beluga whale (Delphinapterus leucas).

Like other toothed whales, belugas produce sound through pneumatic actuation of two phonic lip pairs, but it is unclear whether both pairs are actuated concurrently to generate a single sound (the dual actuation hypothesis) or laterally in the production of their rich vocal repertoires. Here, using suction cup hydrophones on the head of a trained beluga whale, we measured seven different communication signal types and echolocation clicks in order to test the hypothesis that belugas produce distinct sounds unilaterally. We show that, like other delphinoids, belugas produce echolocation clicks with the right phonic lips and tonal sounds from the left. We also demonstrate for the first time that the left phonic lips are responsible for generating communication signals other than tonal sounds. Thus, our findings provide empirical support for functionalized laterality in delphinoid sound production, in keeping with the functional laterality hypothesis of vocal-motor control in toothed whales.

Feline vocal communication.

Cat vocalizes to communicate with another and express their internal states. The vocal repertoire of the cat is wide and up to 21 different vocalizations have been described in the literatures. But it is more than probable that the repertoire contains more types of vocalizations. An ethogram was created in this paper describing the actual known vocalisations of the domestic cat based on an auditory classification. However, the audiogram allows also a visual classification which can increase the accuracy of vocalization differentiation. The classification can be risky as it is sometimes unclear if different types of vocalizations are produced in different environments or if a unique type of vocalization is used with variation in the acoustic parameters. As an example, isolation calls produced by kittens differ depending on the context. The environment has an important impact on the vocal behaviour and thus feral cats and pet cats vocalize differently. Pet cats are thus able to create an efficient communication with humans thanks to the flexibility of vocalisation behaviours. This review allowed us to create a simple model of the cat vocal repertory.

From Perception to Action: The Role of Auditory Input in Shaping Vocal Communication and Social Behaviors in Birds

Acoustic communication signals are typically generated to influence the behavior of conspecific receivers. In songbirds, for instance, such cues are routinely used by males to influence the behavior of females and rival males. There is remarkable diversity in vocalizations across songbird species, and the mechanisms of vocal production have been studied extensively, yet there has been comparatively little emphasis on how the receiver perceives those signals and uses that information to direct subsequent actions. Here, we emphasize the receiver as an active participant in the communication process. The roles of sender and receiver can alternate between individuals, resulting in an emergent feedback loop that governs the behavior of both. We describe three lines of research that are beginning to reveal the neural mechanisms that underlie the reciprocal exchange of information in communication. These lines of research focus on the perception of the repertoire of songbird vocalizations, evaluation of vocalizations in mate choice, and the coordination of duet singing.

The "Law of Brevity" in animal communication: Sex-specific signaling optimization is determined by call amplitude rather than duration.

The efficiency of informational transfer is one of the key aspects of any communication system. The informational coding economy of human languages is often demonstrated by their almost universal fit to Zipf's “Law of Brevity,” expressing negative relationship between word length and its usage frequency. Animal vocal systems, however, provided mixed results in their adherence to this relationship, potentially due to conflicting evolutionary pressures related to differences in signaling range and communicational needs. To examine this potential parallel between human and animal vocal communication, and also to explore how divergent, sex‐specific, communicational settings affect signaling efficiency within a species, we examined the complete vocal repertoire of rock hyraxes (Procavia capensis). As male and female hyraxes differ in their sociality levels and male hyraxes vocal repertoire is dominated by sexual advertisement songs, we hypothesized that sex‐specific vocal repertoires could be subjected to different signaling optimization pressures. Our results show that the sexes differ in repertoire size, call usage, and adherence to coding efficiency principles. Interestingly, the classic call length/call usage relationship is not consistently found in rock hyraxes. Rather, a negative relationship between call amplitude and call usage is found, suggesting that the efficiency of the vocal repertoire is driven by call amplitude rather than duration. We hypothesize that, in contrast to human speech that is mainly intended for short distance, the need for frequent long‐range signaling shapes an animal's vocal repertoire efficiency according to the cost of call amplitude rather than call length. However, call duration may be a secondary factor affecting signaling efficiency, in cases where amplitude is under specific selection pressures, such as sexual selection.

The Vocal Repertoire of Golden-Faced Sakis, Pithecia chrysocephala, and the Relationship Between Context and Call Structure

Vocalizations are a vital form of communication. Call structure and use may change depending on emotional arousal, behavioral context, sex, or social complexity. Pithecia chrysocephala (golden-faced sakis) are a little-studied Neotropical species. We aimed to determine the vocal repertoire of P. chrysocephala and the influence of context on call structure. We collected data June–August 2018 in an urban secondary forest fragment in Manaus, Amazonian Brazil. We took continuous vocal recordings in 10-min blocks with 5-min breaks during daily follows of two groups. We recorded scan samples of group behavior at the start and end of blocks and used ad libitum behavioral recording during blocks. We collected 70 h of data and analyzed 1500 calls. Lowest frequencies ranged 690.1–5879 Hz in adults/subadults and 5393.6–9497.8Hz in the only juvenile sampled. We identified eight calls, three of which were juvenile specific. We found that, while repertoire size was similar to that of other New World monkeys of similar group size and structure, it also resembled those with larger group sizes and different social structures. The durations of Chuck calls were shorter for feeding contexts compared to hostile, but frequencies were higher than predicted if call structure reflects motivation. This finding may be due to the higher arousal involved in hostile situations, or because P. chrysocephala use Chuck calls in appeasement, similar to behavior seen in other primates. Call structures did not differ between sexes, potentially linked to the limited size dimorphism in this species. Our findings provide a foundation for further investigation of Pithecia vocal behavior and phylogeny, as well as applications for both captive welfare (stress relief) and field research (playbacks for surveys).

Influence of season and social context on male giant panda (Ailuropoda melanoleuca) vocal behaviour.

Documenting the different social and behavioural contexts that vocalisations are produced in remains an important step towards understanding the functional relevance of specific call types in a given species’ vocal repertoire. In this study we investigated whether seasonal differences and the presence or absence of male and female conspecifics influence the production of male giant panda vocal signals. To this end, captive male giant pandas were observed during and outside of the breeding season in three social contexts: only male conspecific neighbours, only female conspecific neighbours, and a context with no neighbours. We found that males were more likely to bleat, chirp, honk and moan during the breeding season, and showed a tendency to growl more outside of the reproductive period. The contextual analysis revealed that bleats were more likely to be produced by males when opposite-sexed conspecifics are in close attendance during the breeding season. Conversely, males were more likely to chirp when neighboured by males than females or no neighbours. In addition, males were more likely to honk in the absence of neighbouring conspecifics during the breeding season, raising the possibility that these calls function to signal location and gain the attention of potential mates. Moans were produced more often when male giant pandas had male than female neighbours during the breeding season, which may reflect mild aggression towards these same-sexed rivals, whereas the production of barks and growls did not vary according to season or the sex of conspecific neighbours. Our findings underscore the importance of male giant panda bleats for coordinating reproduction and promoting contact with potential mating partners in this non-gregarious species, and yield fresh insights into the function of male honks that warrant further investigation. They also provide a basis for comparison with free-ranging giant panda vocal behaviour that could potentially inform conservation efforts.