Song Matching Research Articles

Song overlapping and matching during low‐arousal singing and their relation to visual ornaments, parental care and breeding success in the great tit (Parus major)

AbstractEavesdropping on interactions between conspecific animals provides a low‐cost method for assessing other individuals. Asymmetries in territorial counter‐singing interactions in songbirds provide a rich source of information for eavesdroppers about differences between the singers. Yet, little is known about the relationship between interactive singing in a natural, low‐arousal context among territorial neighbours and individual traits of males. We used a microphone array to monitor natural counter‐singing interactions in great tits (Parus major) during nest building, at the onset of the breeding season. We quantified song overlapping and song matching for 30 pairs (dyads) of interacting males, singing at their nest, respectively. We then compared these behaviours to five traits for 28 males: body condition, plumage ornamentation, offspring provisioning behaviour, offspring weight and breeding site quality. We found no relationship between a male song overlapping or matching behaviour and any of the measured traits. Therefore, our results do not support the idea that short‐term asymmetries in low‐arousal long‐range singing interactions among neighbours reflect differences in these fitness‐related traits. Instead, our findings suggest that such singing asymmetries have less signal value in the absence of an immediate conflict but instead reflect short‐term motivational differences, as shown in previous investigations.

Song type and song type matching are important for joint territorial defense in a duetting songbird.

Birds have a diverse acoustic communication system, with species-specific repertoires facilitating more complex behaviors in terms of both within- and between-pair communications. Certain song types are produced for specific functions, such as aggressive encounters. In addition, song matching behaviors, whereby neighboring individuals match song types, can be used in aggressive interactions as a sophisticated acoustic behavior. In this study, we examined the functions of song types, in a duet context, of male yellow-breasted boubous (Laniarius atroflavus), an Afromontane bush-shrike with a vocal sexual dimorphism. We aimed at assessing whether, structurally, certain song types elicited a heightened reaction than others and also whether song matching affected response behavior. A dual speaker playback procedure was performed for 18 pairs of boubous, each pair being exposed to duets with three different male song types. We found differences in response toward the different duet types but these differences resulted from the amount at which males matched different song types. Pairs responded stronger when a focal male matched the playback type, and matching was significantly more often found in cases where the rarest type of male song was used. We found no sex differences in terms of response strength to playback type. Our results indicate a two-level way of coding aggression toward intruding pairs. The yellow-breasted boubous utilize their repertoires, linking matching with structure in order to show aggression in terms of territory defense and sexual conflict. This study also confirms joint territorial defense as a main function of duets in this species.

Song matching in a long‐lived, sedentary bird with a low song rate: The importance of song type, song duration and intrusion

AbstractTerritorial songbirds often match the song features or singing patterns of rivals, commonly as an aggressive signal. Most studies of song matching have been on Northern Hemisphere species with short lifespans and high song rates, but vocal matching is predicted to be affected both by longevity and territorial stability. We studied song matching in males of the white‐browed scrubwren, Sericornis frontalis, a long‐lived, sedentary, territorial Australian songbird. We quantified natural song rate and diversity, and then conducted three playback experiments to test: (a) whether males match by song type; (b) how they respond physically and vocally to territorial intrusion; and (c) whether they match by song length, and use it as an agonistic signal. Males naturally had very low song rates, singing on average less than three times per hour, and moderate repertoires, with an estimated mean of 17.5 song types for individual males. Males did not engage in extended counter‐singing bouts. The first experiment showed that males matched the song type of immediate neighbours almost 90% of the time, if that type was in their repertoire. The remaining experiments revealed that song‐type matching was an aggressive signal; males responded more aggressively to, and were more likely to match, playback simulating a neighbour's territorial intrusion than song from their shared boundary. Males did not match songs by length, but they produced longer songs after simulated intrusion. Males also responded more aggressively to playback of longer songs that simulated intrusion, but less aggressively to longer songs from the territory boundary. Overall, we show that sedentary, long‐lived songbirds with low song rates, can use song‐type matching as an aggressive signal to communicate with neighbours and intruders. Song length had a different role in communication, possibly related to individual quality or territory ownership.

Song Does Not Function as a Signal of Direct Aggression in Two Leaf-Warbler Species

In many songbirds, males vary aspects of their singing behaviour when engaged in territorial interactions. Song rate, song type switching rate, song matching, song overlapping, and the use of specific song or call types have all been proposed to be aggressive signals. It is not clear why such variability in aggressive signaling mechanisms exists among different species. We used a comparative approach to study how two Phylloscopus warbler species respond to playback-simulated territorial intrusion. We examined whether the spontaneous songs of Large-billed Phylloscopus magnirostris and Sulphur-breasted P. ricketii leaf-warblers differed from songs produced in response to playback. Song bouts were analysed by measuring 10–12 parameters, but we found no differences between spontaneous songs and playback responses in either species. All males clearly responded to playback by approaching the loudspeaker and flying around it. Large-billed Leaf-warblers produced ‘crackling’ sounds in response to playback more frequently than during spontaneous singing, whereas the usually highly vocal Sulphur-breasted Leaf-warblers possibly (and surprisingly) did not use vocalizations (either songs or calls) to signal direct aggression. A comparison with other Phylloscopus species revealed that even closely related species (i.e. from a single genus) might use different strategies when responding to simulated territorial intrusion. The aggressive signalling strategy is therefore a labile trait that can potentially be exposed to fast evolutionary change.

Singing of Claudia’s Leaf-warbler (Phylloscopus claudiae) in aggressive contexts: role of song rate, song type diversity and song type transitional pattern

In many songbirds, males vary certain aspects of their singing behavior when engaged in territorial interactions. Song rate, song type switching rate, song matching, song overlapping, and the usage of specific song types were proposed to be aggressive signals. It is well known that transitions between different song types in a song sequence are non-random in many species, but the signaling significance of non-random vocal streams is poorly understood. We asked whether singing plays a role in male–male interactions in Claudia’s Leaf-warbler. Along with more traditional metrics (i.e., song length, song rate, song type switching rate and song type diversity), we used (1) song sequence linearity (SLIN) and consistency (SCONS) indexes, and (2) applied an information theory approach by means of a first-order relative entropy (RE1) calculation to analyze the role of song type transitional patterns in male–male interactions. The study was conducted in April–June 2016 in Hupingshan National Nature Reserve, Hunan province, China. We simulated territorial intrusion by broadcasting Claudia’s Leaf-warbler songs in territories. Experiments involved 14 different males. A comparison of spontaneous singing with that elicited by playback showed that song rate and song type diversity increased, and that entropy decreased. By contrast, SLIN and SCONS, though significantly correlated with RE1, did not differ between spontaneous singing and singing in response to playback. The decrease of entropy means that the transitions between different song types in a song sequence were determined more by specific factors and predictable and thus more non-random. However, these results were weak, as the decrease of RE1 did not coincide with the expected increase of SLIN, SCONS and S. Our results are thus partly consistent with the idea that non-random vocal structures, along with other song parameters, could play a role in male–male competition.

Use of Tonic and Raga as Indices for a Query by Example based Music Information Retrieval System

Background and Objectives: A Music Information Retrieval Systems deal with retrieving music from a corpus based on user’s input. Query by Example (QBE) and Query By Humming (QBH) are the two content baste music information retrieval systems. Methods/Statistical Analysis: In this paper, a Query By Example (QBE) based Music Information Retrieval system is proposed, where the characteristics of Carnatic music are used as indices for identifying similar matches to an input song. The system begins by introducing a novel focused crawler mechanism that explores the World Wide Web in a methodical manner to harvest music for the database required. The crawled music is then downloaded, and a local repository of songs is created. Carnatic music features like Tonic and Raga are extracted from the crawled songs and these songs are indexed into the database. Tonic identification is a challenging problem and in this work, a new algorithm for estimation of tonic is designed. Using the Tonic, the Raga of the song is identified and these features are used in a modified, optimized version of the Multi-key hashing technique to index the songs and improve the speed of retrieval. During a user query, which is by example, the same features are extracted, compared with the features of the songs indexed in the database, based on the search option provided by the user, and the best matching songs are retrieved, by proposing a new ranking algorithm based on Raga and Tonic similarity. Findings: The proposed system recognized the Tonic of the song with accuracy while the Raga of the song is recognized if the input music piece is free of Gamaka. Application/ Improvements: Music information retrieval system for entertainment, therapy and helps in content based retrieval of music and the system could be improved to handle Gamakas in the input music piece.

Singing onstage: female and male common nightingales eavesdrop on song type matching

In bird communication, listening individuals may obtain information on the quality and motivation of a male not only from solo-singing, but also from song interactions and listeners base their future decisions in territorial and mating contexts on such public information. Eavesdropping on male interactions may thus have a strong influence on sexual selection. In singing interactions, temporal coordination (e.g. overlapping vs. alternating) of two singers as well as structural interaction patterns (e.g. song type matching or repertoire matching) have been described, but the latter is far less studied. By conducting dual-speaker playback experiments with common nightingales Luscinia megarhynchos, we simulated an interaction where one singer was repeatedly song–type matching his counterpart. Playbacks were broadcast to male and female nightingales, and their approach behaviour and singing responses (in the case of male focals) were analysed. We found that both, males and females, spent more time with the matched bird, whereas males additionally sang more songs towards the matching bird. This can be taken as strong hint that eavesdropping occurs in nightingale communication and that listening to male vocal contests might be an important strategy for both sexes to adjust their behavioural output. With regard to the function of song matching, we assume that song-matching is not an aggressive signal per se in nightingales. We rather conclude that vocal leaders within an interaction, here the matched bird, may elicit stronger responses in conspecifics than vocal followers, here the matching bird.

How Reliable Is Song Learning Accuracy as a Signal of Male Early Condition?

That many species of songbirds learn their songs imitatively is well established, but it is less clear why they do so. A component of the developmental-stress hypothesis posits that young males in good condition learn songs more accurately than males in poor condition and that females use learning accuracy as an honest signal of male developmental history. An unresolved problem is how females reliably assess learning accuracy when they are not certain of the identity of the male's tutor and thus the specific model from which a song was copied. We therefore investigated whether song learning accuracy assessment (SLAA) can be reliable, using evolutionary simulation models of song learning. We found that SLAA is indeed less reliable than assessment in which male signals are compared to an unlearned standard, as a result of three types of errors in matching songs to their models. In the simplest models, SLAA was particularly unreliable, but when the model is made more realistic by including features such as geographically constrained learning, repertoire complexity, and, in particular, song categorization, the reliability of SLAA increased. Our results demonstrate a range of conditions under which the assessment of song learning accuracy might be reasonably reliable and therefore likely to evolve.

Genes and song: genetic and social connections in fragmented habitat in a woodland bird with limited dispersal

Understanding the processes leading to population declines in fragmented landscapes is essential for successful conservation management. However, isolating the influence of disparate processes, and dispersal in particular, is challenging. The Grey Shrike-thrush, Colluricincla harmonica, is a sedentary woodland-dependent songbird, with learned vocalizations whose incidence in suitable habitat patches falls disproportionally with decline in tree cover in the landscape. Although it has been suggested that gaps in tree cover might act as barriers to its dispersal, the species remains in many remnants of native vegetation in agricultural landscapes, suggesting that it may have responded to habitat removal and fragmentation by maintaining or even increasing dispersal distances. We quantified population connectivity of the Grey Shrike-thrush in a system fragmented over more than 120 years using genetic (microsatellites) and acoustic (song types) data. First, we tested for population genetic and acoustic structure at regional and local scales in search of barriers to dispersal or gene flow and signals of local spatial structuring indicative of restricted dispersal or localized acoustic similarity. Then we tested for effects of habitat loss and fragmentation on genetic and acoustic connectivity by fitting alternative models of mobility (isolation-by-distance [the null model] and reduced and increased movement models) across treeless vs. treed areas. Birds within -5 km of each other had more similar genotypes and song types than those farther away, suggesting that dispersal and song matching are limited in the region. Despite restricted dispersal detected for females (but not males), populations appeared to be connected by gene flow and displayed some cultural (acoustic) connectivity across the region. Fragmentation did not appear to impact greatly the dispersal of the Grey Shrike-thrush: none of the mobility models fit the genetic distances of males, whereas for females, an isolation-by-distance model could not be rejected in favor of the models of reduced or increased movement through treeless gaps. However, dissimilarities of the song types were more consistent with the model of reduced cultural connectivity through treeless areas, suggesting that fragmentation impedes song type sharing in the Grey Shrike-thrush. Our paper demonstrates that habitat fragmentation hinders important population processes in an Australian woodland bird even though its dispersal is not detectably impacted.

Song-type sharing and matching in a bird with very large song repertoires, the tropical mockingbird

Summary Song-type matching, a behaviour of some songbirds in which one individual replies to another’s song with a matching song type, has been studied primarily in birds that have small to moderately sized song repertoires (<15 song types) and that share only a few song types with neighbours. Few previous studies have examined song-type matching in species with very large song repertoires, in which birds can share larger numbers of songs with neighbours and matching particular song types might be more challenging. Here we describe frequent and rapid song-type matching in a population of tropical mockingbirds, Mimus gilvus. Males had repertoire sizes of about 133 distinct song types on average which were delivered with high versatility. Territorial neighbours shared significantly more song types than did nonneighbours, and neighbouring males matched each other’s songs frequently and often with surprising speed. Overlapping of songs occurred at approximately chance levels. Song-type matching in these birds could indicate more than just aggressive intentions, which is the presumed function of this behaviour in species with smaller repertoires. In tropical mockingbirds, rapidly matching the songs of neighbours could provide information to listeners about a singer’s experience or abilities.

The deterrent effect of bird song in territory defense

Using the responses of territory owners to playback to infer the territorial function of acoustic signals is common practice. However, difficulties with interpreting the results of such experiments have obscured our understanding of territorial signalling. For instance, a stronger response to playback is often interpreted as more aggressive, but there is no consensus as to whether this should be in response to the least or most threatening simulated intruder. Rather than following a gradual increase or decrease, the relationship between signal intensity and response strength may instead describe a peaked curve. We manipulated banded wren (Thryophilus pleurostictus) songs to simulate low-, median-, and high-performance singers and used these songs as stimuli in playback experiments. Banded wrens were less likely to approach the high-performance stimulus compared with the low- and median-performance stimuli. However, the birds that did approach the high-performance stimulus sang more than those that approached the low-performance stimulus. In addition, birds were more likely to match the songs when exposed to the median- and high-performance stimuli compared with the low-performance stimuli, and song matching predicted approach behavior. These results are in accordance with theoretical models of aggressive encounters in which low-performance opponents are challenged without further assessment. Median- and high-performance opponents, however, may require further assessment, and the latter may be perceived as too intimidating for approach.

Constrained Performance in a Communication Network: Implications for the Function of Song‐Type Matching and for the Evolution of Multiple Ornaments

Many species of territorial songbirds exhibit a behavior known as song-type matching, in which a male sings the same song type that his neighbor is singing. Song-type matching is associated with increased aggression, but researchers have not come to a consensus on its adaptive function. Building on studies that identify singing performance as a variable relevant to sexual selection, we hypothesize that higher-performance singers benefit from matching their opponent's song type because matching improves eavesdroppers' ability to compare the two males' performances. We present a model of song-type choice that predicts that males that can outperform their rivals benefit by matching. In contrast, lower-performance males should avoid both matching and being matched. Our hypothesis is compatible with some existing hypotheses of song-matching function, but it is not compatible with the hypothesis that song matching is a conventional signal of aggression. We offer unique predictions that could be used to test our idea. We speculate that lower-performance individuals might have driven the evolution of repertoire complexity because they stand to benefit from novel, unmatchable songs. The phenomenon that dissimilar signals are less accurately compared than similar signals may favor the evolution of multiple ornaments and of plastic signal development (e.g., song learning) in general.

Frequency matching, overlapping and movement behaviour in diurnal countersinging interactions of black-capped chickadees

Animal signalling contests are used by males to advertise to choosy females and to repel male competitors. During countersinging interactions in songbirds, males vary the type and timing of songs with respect to their opponent's behaviour. In black-capped chickadees, Poecile atricapillus, frequency matching and song overlapping appear to be important in territory defence and mate attraction. We studied frequency matching and overlapping behaviour during 100 naturally occurring diurnal song contests among male chickadees using an Acoustic Location System (ALS). The ALS consisted of 16 microphones that recorded countersinging interactions across multiple territories simultaneously, allowing us to triangulate the position of individuals based on delays in sound arrival at each microphone. We used the ALS to record 10 neighbourhoods of chickadees whose relative dominance status had been tabulated during the preceding winter. In 80% of contests there was at least one instance of overlapping between the contestants. In 37% of contests, the contestants were frequency matched within 50 Hz. Neither overlapping nor matching occurred at levels different from those expected by chance. However, contests that contained frequency matching had significantly more instances of overlapping than nonmatched contests. There were no rank-related differences in the proportion of opponents' songs that were frequency matched or overlapped. In using an Acoustic Location System to record entire neighbourhoods of territorial songbirds, this study is the first to quantify song matching and overlapping by free-living animals in the context of natural countersinging exchanges between familiar territorial neighbours.

The Effects on Words of a Song and Picture Cards Matching to Develop Vocabulary Ability for Children with Language Delayed

The Effects on Words of a Song and Picture Cards Matching to Develop Vocabulary Ability for Children with Language Delayed

Song matching, overlapping, and switching in the banded wren: the sender's perspective

Interpreting receiver responses to on-territory playback of aggressive signals is problematic. One solution is to combine such receiver-perspective experiments with a sender-perspective experiment that allows subjects to demonstrate how their choice of singing strategies is associated with their approach behavior. Here we report the results of a sender-perspective study on the banded wren (Thryothorus pleurostictus), and combine information on context and results of previous receiver-perspective experiments to clarify function. Territorial males were presented with a 5-min playback consisting of song types present in their repertoire. We assessed the degree to which the subjects' song matching rate, overlapping rate, and song-type versatility were correlated with their approach latency, closeness of approach, latency to first retreat, and time spent close to the speaker. Male age, breeding stage, and features of the playback stimuli were also considered. Song matching was associated with rapid and close approach, consistent with the receiver-perspective interpretation of type matching as a conventional signal of aggressive motivation. Overlapping was associated with earlier retreat, and together with the aversive receiver response to our previous overlapping playback experiment suggests that overlapping is a defensive withdrawal signal. High versatility was associated with slower first retreat from the speaker and high levels of reciprocal matching between subject and playback. Males with fledglings sang with particularly low versatility and approached the speaker aggressively, whereas males with nestlings overlapped more and retreated quickly. Finally, older males matched more but overlapped less.

The Shazam music recognition service

Guided by a user's query-by-example music sample, it delivers the matching song, as well as related music information, of immediate interest to the user.

Duet duels: sex differences in song matching in duetting eastern whipbirds

The dynamics of vocal duels between rival male songbirds have been the subject of intense investigation over the last few decades. However, countersinging interactions between females and duetting birds have received considerably less attention. We compared patterns of song type matching in male and female eastern whipbirds, Psophodes olivaceus, using playback experiments to simulate intrusion by solo singing and duetting intruders. Eastern whipbirds sing a repertoire of sex-specific solo song types, which they combine nonrandomly to form specific duet types, initiated exclusively by the male. During playbacks, individuals could sing either a song type that matched the song type of a same-sex rival or one that fitted the song type of their partner. We found markedly different patterns of song type matching between the sexes. Both male and female eastern whipbirds matched the songs of same-sex intruders during solo singing song duels. However, when forming a duet, females selected a song type that fitted the song of their partner in preference to matching the song type of a female rival, whereas males preferentially matched a rival. We suggest that these sex differences in song type matching behaviour are the result of different strategies of mate and territory defence. Rather than being a purely cooperative signal, duets may be the result of sexual conflicts, with females forced to defend their position within the partnership, either by showing commitment to their partner or by deterring female rivals through display of their pair bond status.

Heterospecific song matching in two closely related songbirds (Parus major and P. caeruleus): great tits match blue tits but not vice versa

To date, song research has focused primarily on the interactions of conspecifics. However, frequent interactions of songbirds with heterospecifics may necessitate adequate communication outside the species boundary. In this study, we focus on heterospecific communication behaviour of two small sympatric congeneric passerines, great and blue tits (Parus major and Parus caeruleus), which breed in overlapping territories and compete for food and nesting cavities. By means of a first playback experiment, we show that (1) heterospecific matching (imitating songs of the other species) is a strategy frequently used by great tits but not by blue tits, (2) both blue tit trilled and untrilled song can be accurately matched by great tits and that (3) almost half of the great tits in our study population match at least one blue tit song across all studied breeding stages, indicating that this heterospecific matching behaviour is a common feature in this population. A second playback experiment showed that these great tit imitations of blue tit songs do not function in intraspecific communication between male great tits. Hence, these heterospecific imitations appear to be designed for interspecific communication with blue tits. These findings suggest a strong heterospecific influence on the vocal learning process, repertoire composition and repertoire use in great tits and provide a possible mechanism that can drive song convergence in songbirds.

Habitat fragmentation affects culture transmission: patterns of song matching in Dupont's lark

Summary Males of many bird species match song with neighbours during territorial interactions. Although bird vocal mimicry has received much attention, the relationships between song variation and ecological factors such as landscape geometry and habitat fragmentation are still poorly known, and most previous research has been limited to one or a few populations of a species. In this study we analysed the spatial patterns and ecological determinants of song matching in Dupont's lark Chersophilus duponti, a rare and specialized steppe passerine. By recording bird songs from 21 Spanish and Moroccan localities, we analysed the effect of habitat fragmentation and the availability of suitable steppe habitat on the patterns of song matching in Dupont's lark, controlling for other potential determinants such as period in the breeding season, intensity of competition, geographical location and spatial distribution of individuals. Both song‐type sharing (match of song types in the repertoire) and spectrotemporal matching (convergence in the acoustic features of the same song type) were greater between counter‐singing neighbours than between non‐neighbours, and spatial autocorrelation (similarities between singing individuals) only occurred at short distances. The study localities differed in the amount of overall acoustic matching between individuals, seemingly as a consequence of local differences in the intensity of male competition and in the availability of suitable habitat. The levels of song‐type sharing between non‐neighbours tended to increase and those among neighbours to decrease with the increase of steppeland availability. Moreover, the existing differences in sharing between neighbours and non‐neighbours were significantly affected by the presence of elements of fragmentation in the steppe. In fragmented habitats, song sharing among neighbours was enhanced, possibly because of harsher competition for limited resources; conversely, sharing among non‐neighbours dropped, probably because of the lack of interactions among individuals isolated by habitat barriers. Synthesis and applications. Anthropogenic habitat barriers could alter bird perception of the spatial distribution of rivals over distance, leading to a contraction of the spatial range of the individual acoustic niche. We suggest that communication systems of habitat‐sensitive species might be used as a behavioural indicator of anthropogenic environmental deterioration. Because of their rapidly evolving cultural nature, bird vocalizations might become an early warning system detecting the effects of fragmentation over relatively short times and before other indicators (such as genetic markers) show any change.

Duet singing and repertoire use in threat signalling of individuals and pairs

Song-type switching rate and song matching have been shown to function as territorial signals in male solo song but, to our knowledge, seem not to have been previously studied in a duetting species. We studied the plain wren (Thryothorus modestus zeledoni), to test whether duets signalled threat through song-switching rates, or through phrase type or duet type matching. Increases in the rate of song switching appear to function as an anti-habituation device rather than as a specific signal of threat. Fitting with previous results that same-sex individuals share phrase types, but pairs do not share duet types, both males and females used duets to phrase type match to playback. Pairs, however, did not duet type match in response to playback, and this suggests that within the cooperative territory defence of the duet, each sex is targeting its aggression at same-sex competitors.