Article

The Chorus Song of Cooperatively Breeding Laughing Kookaburras (Coraciiformes, Halcyonidae: Dacelo novaeguineae): Characterization and Comparison Among Groups

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Abstract

I studied vocalizations of laughing kookaburras in Western Australia by sampling the laugh-song choruses of eight different groups and the isolated vocalizations of four individuals of this cooperatively breeding species. These data provided a description of the acoustic structure of vocal elements of the laugh song and a between-group comparison of laugh choruses. I identified six different categories of syllables: some syllable types appear graded with modal forms predominating. Group choruses were produced by several birds vocalizing simultaneously, usually following initiation by a single bird producing one of two typical introductory sets of syllable repetitions. Statistical analyses of samples of mid-chorus vocalizations of kookaburra groups revealed that the samples from each of the eight groups clustered in principal coordinate space and the group clusters segregated from each other to a significant degree. Linear discriminant analysis assigned 24 of the 25 samples to their correct groups. These results suggest that there is group-specific vocal signature information in the laugh chorus. The within-group similarity and between-group differences may result from heritable variation or from imitation learning. Observations of the contexts of the laugh chorus vocalization supported the interpretations of others that the chorus song is involved in group advertisement of territory occupancy and in defense of the communal borders.

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... On the other hand, vocal group signature studies with bird groups of innate vocalization are scarce (Baker, 2004;Radford, 2005). Among these innate vocalizations birds, the Smooth-billed Ani (Crotophaga ani Linnaeus, 1758) can be highlighted. ...
... This is consistent with the circumstances of these vocalizations, since "Flight" is used in the context of group cohesion during flight, as also observed in budgerigars (Hile & Striedter, 2000), whereas "Vigil" is used in territory surveillance and monitoring, alerting the other members of the group about any imminent danger. This type of vocal signature is related to various mammal groups, such as bats (Boughman, 1998;Wenrickboughman & Swilkinson, 1998;Gillam & Chaverri, 2012;Knörnschild et al., 2012), wolves (Zaccaroni et al., 2012), gazelles (Volodin et al., 2014), meerkats (Townsend et al., 2010), whales (Vester et al., 2016), as well as for birds that exhibit vocalization learning (Mammen & Nowicki, 1981;Nowicki, 1983Nowicki, , 1989Baker, 2004;Elie & Theunissen, 2018;Martins et al., 2018;Araya-Salas et al., 2019;Benti et al., 2019). However, as previously mentioned, studies in birds with innate vocalization are scarce (Baker, 2004;Radford, 2005). ...
... This type of vocal signature is related to various mammal groups, such as bats (Boughman, 1998;Wenrickboughman & Swilkinson, 1998;Gillam & Chaverri, 2012;Knörnschild et al., 2012), wolves (Zaccaroni et al., 2012), gazelles (Volodin et al., 2014), meerkats (Townsend et al., 2010), whales (Vester et al., 2016), as well as for birds that exhibit vocalization learning (Mammen & Nowicki, 1981;Nowicki, 1983Nowicki, , 1989Baker, 2004;Elie & Theunissen, 2018;Martins et al., 2018;Araya-Salas et al., 2019;Benti et al., 2019). However, as previously mentioned, studies in birds with innate vocalization are scarce (Baker, 2004;Radford, 2005). ...
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Vocal plasticity reflects the ability of animals to vary vocalizations according to context (vocal repertoire) as well as to develop vocal convergence (vocal group signature) in the interaction of members in social groups. This feature has been largely reported for oscine, psittacine and trochilid birds, but little has been investigated in birds that present innate vocalization. The smooth-billed ani (Crotophaga ani) is a social bird that lives in groups between two and twenty individuals, and which presents innate vocalization. Here we analyzed the vocal repertoire of this species during group activities, and further investigated the existence of a vocal group signature. The study was conducted in the Southeast of Brazil between May 2017 and April 2018. Two groups of smooth-billed anis were followed, Guararema and Charqueada groups, and their vocalizations were recorded and contextualized as to the performed behavior. The vocal repertoire was analyzed for its composition, context and acoustic variables. The acoustic parameters maximum peak frequency, maximum fundamental frequency, minimum frequency, maximum frequency and duration were analyzed. To verify the vocal signature of the group, we tested whether there was variation in the acoustic parameters between the monitored groups. We recorded ten vocalizations that constituted the vocal repertoire of the Smooth-billed Ani, five of which (“Ahnee”, “Whine”, “Pre-flight”, “Flight” and “Vigil”) were issued by the two groups and five exclusive to the Charqueada group. There were significant differences in the acoustic parameters for “Flight” and “Vigil” vocalizations between the groups, suggesting vocal group signature for these sounds. We established that the Smooth-billed Ani has a diverse vocal repertoire, with variations also occurring between groups of the same population. Moreover, we found evidence of vocal group signature in vocalizations used in the context of cohesion, defense and territory maintenance.
... The combination of SPCC and PCoA is robust in its ability to separate the effects of shared time–frequency patterns from those of duration, noise and harmonic variation (Cortopassi & Bradbury 2000), and the general approach used here mirrors that of previous studies for the comparative analysis of complex broadband sounds (e.g. Cortopassi & Bradbury 2000; Baker 2004). Initial analysis, to assess quantitatively the vocal similarity of rallies recorded from each woodhoopoe group and those from different groups, focused on the five rallies recorded from each of the 22 groups that retained the same composition of adult individuals throughout the 1999–2000 season. ...
... However, groups having the same size and sex ratio were still acoustically distinct, suggesting that rallies include a group-specific vocal signature independent of these factors. Although much research has been conducted on individual and kin recognition in birds (reviewed in Komdeur & Hatchwell 1999), only recently has there been any evidence of a vocal signature within the combined chorusing of a cooperatively breeding species (the laughing kookaburra, Dacelo novaegui- neae; Baker 2004). Baker (2004) offered only preliminary evidence, however; calls were recorded on 2 consecutive days from eight different groups, and no account was taken of differences in group size or sex ratio. ...
... ture independent of these factors. Although much research has been conducted on individual and kin recognition in birds (reviewed in Komdeur & Hatchwell 1999), only recently has there been any evidence of a vocal signature within the combined chorusing of a cooperatively breeding species (the laughing kookaburra, Dacelo novaegui- neae; Baker 2004). Baker (2004) offered only preliminary evidence, however; calls were recorded on 2 consecutive days from eight different groups, and no account was taken of differences in group size or sex ratio. The current study provides a more comprehensive analysis of the evidence for group-specific vocal signatures. ...
Article
Group displays involving vocal choruses are a prominent feature of many avian cooperative-breeding systems. The existence of group-specific vocal signatures within these choruses could assist territory owners when assessing the threat posed by different intruding groups. To investigate the possible presence of such signatures, I examined the choruses (‘rallies’) given by 22 green woodhoopoe, Phoeniculus purpureus, groups over two consecutive seasons. A rally involved the combined cackling of adult group members. Statistical analysis of midrally vocalizations, when all group members were calling, revealed that samples from the same group clustered in principal coordinate space, and the group clusters segregated from each other to a significant degree. This segregation might theoretically arise from differences in group size and sex ratio, especially since the vocalizations are sexually dimorphic. However, groups containing the same numbers of males and females had rallies that were significantly different acoustically. Groups that maintained the same composition of individuals produced acoustically similar rallies across seasons, while those that changed membership produced significantly different rallies. The group signature is therefore most likely to result from group members producing their own individual vocal programmes, but participating in a similar way for every rally. In a playback experiment, groups responded significantly more rapidly to strangers and to neighbours on the wrong boundary than to neighbours in their expected place. Woodhoopoes therefore appeared capable of distinguishing between groups on the basis of their vocal signatures, representing the first evidence of the ‘dear-enemy’ phenomenon in a group-living species.
... By contrast, the vocal signaling systems of most non-passerines remain little studied. Non-passerines typically do not sing, but instead produce calls in a variety of contexts, including territorial interactions (Seddon et al. 2002, Radford 2003, Baker 2004, coordination of reproductive activities ...
... We used SAP to measure (1) call duration (ms), (2) mean, minimum, maximum, and variance of mean frequency (Hz), frequency modulation (FM, degrees), and Weiner entropy, (3) mean, minimum, and maximum values of peak frequency (Hz) and duration of acoustic state (ms), (4) mean and maximum values of continuity over frequency (Hz) and continuity over time (ms), and (5) mean and variance of pitch (Hz), goodness of pitch, and amplitude modulation (AM, 1/t). Variation in these acoustic features maps onto variation in vocal sound production in birds (Baker and Logue 2003). Tchernichovski (2012) and Feher et al. (2009) described these features in detail, but we provide brief definitions below. ...
... For example, a call that modulates linearly from 500 to 1000 Hz and back to 500 Hz would have the same mean pitch, maximum pitch, minimum pitch, and FM as a call that modulates linearly from 1000 to 500 Hz and back to 1000 Hz. Spectrogram cross-correlation is an alternative technique for sound comparison that accounts for variation over the course of the signal, but that technique does not offer descriptive statistics of call structure (Baker and Logue 2003). ...
Article
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Calls are functionally diverse signals that mediate behavior in a wide variety of contexts in both passerines and non-passerines. However, the call-based acoustic communication systems of non-passerines have received less attention from investigators than those of passerines. We examined the vocal repertoire of Smooth-billed Anis (Crotophaga ani), cooperatively breeding cuckoos that live in groups with multiple breeding pairs. We recorded calls from 22 groups over two breeding seasons at the Cabo Rojo National Wildlife Refuge in Puerto Rico. We identified 11 call types and one group vocalization, and used an automated sound measurement program to quantify their acoustic features. Discriminant function analysis (DFA) correctly classified 74.2% of calls based on these features. The vocal repertoire of Smooth-billed Anis is larger than that reported for the three other species in the subfamily Crotophaginae. Smooth-billed Anis have at least two alarm calls, two nest-specific calls, and one nest defense call. We also identified one possible signal of aggressive intent, one possible appeasement signal, and two calls that may communicate identity. The relatively large vocal repertoire of Smooth-billed Anis and association of distinct call types with different functions and contexts supports the main prediction of the social complexity hypothesis, i.e., species with more complex social systems will have more complex communication systems.
... Other expected roles of vocalisations in social species include coordinating group movements (Bousquet et al. 2010), attracting group members (Kennedy et al. 2009), defence of group resources (Baker 2004), anti-predator behaviour (Johnson et al. 2003), maintaining contact with group members (Marler 2004), and maintaining intra-group spacing while foraging (Radford and Ridley 2008). Vocalisations may also function in helping to maintain social bonds (Brown et al. 1988) or mediate social hierarchies (Reyer and Schmidl 1988). ...
... These calls may also function to attract group members to the caller's location (Kennedy et al. 2009). Group cohesion is also important in contexts such as defence of group resources (Reyer and Schmidl 1988;Baker 2004) and calls given during inter-group conflicts, such as the Chee-ow and Chewa-reea calls, may function in signalling and maintaining group identity if they encode information on individual or group identity (Baker 2004;Radford 2004;Townsend et al. 2010). However, the precise function of all Apostlebird calls remains to be investigated in detail. ...
... These calls may also function to attract group members to the caller's location (Kennedy et al. 2009). Group cohesion is also important in contexts such as defence of group resources (Reyer and Schmidl 1988;Baker 2004) and calls given during inter-group conflicts, such as the Chee-ow and Chewa-reea calls, may function in signalling and maintaining group identity if they encode information on individual or group identity (Baker 2004;Radford 2004;Townsend et al. 2010). However, the precise function of all Apostlebird calls remains to be investigated in detail. ...
Article
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The role of acoustic communication in facilitating social interactions and mediating cooperative behaviour has been highlighted by many studies. In the ‘social complexity hypothesis’ of communication, many more specialised signals are likely to evolve in social species where many individuals interact in multiple behaviours. However, before the function of vocalisations in these systems can be elucidated accurately, the characteristics and social context of each vocalisation must be determined. Apostlebirds (Struthidea cinerea) are a highly vocal and social species with an obligate cooperatively breeding life-history. In this study, we describe the environmental and behavioural context of the 17 most common calls from the vocal repertoire of a study population of Apostlebirds in north-western New South Wales. The vocalisations given by individuals ranged from simple, monosyllabic calls through to more complex calls with multiple syllables and frequency modulations. All these calls were broadly categ
... In addition, we analysed the information content of whole song choruses. We hypothesized that bat song choruses encoded information on colony identity and size since this information is also encoded in the communal choruses of other group-living birds and mammals [61][62][63][64] . ...
... The dawn chorus of S. bilineata also encoded information on colony identity. This in is line with findings from group-living birds and mammals which deliver communal choruses in the context of territorial defence (laughing kookaburras 63 , green woodhoopoes 85 , and wolves 64 ). However, we currently do not know whether conspecific bats make use of the colony signature encoded in territorial chorusing. ...
Article
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Male song in birds and mammals is important for repelling rivals, stimulating mates or attracting them to a specific location. Nevertheless, direct experimental evidence for the mate attraction function of male song is limited to a few studies. Here, we provide strong experimental evidence that male songs attract wild female bats (Saccopteryx bilineata). Playbacks of territorial songs reliably elicited phonotaxis in females but not males. Most females captured during playbacks were subadults searching for new colonies to settle in. In S. bilineata, multiple males sing simultaneously at dawn and dusk, thereby creating a conspicuous chorus which encodes information on colony identity and size. Since territorial songs have a large signalling range, male songs constitute acoustic beacons which enable females to localize new colonies. In our playbacks, females strongly preferred local territorial songs over foreign territorial songs from two different locations, indicating that song familiarity influences phonotaxis. Our study provides the first clear experimental evidence that male song elicits female phonotaxis in a non-human mammal. Bats are an especially promising taxon for studying mammalian song since male song has been described in different species with diverse social organisations and natural histories, thus providing exciting opportunities for phylogenetically controlled comparative studies.
... Petrie & Williams 1993). Seasonal vocalizations address competitors, as well as potential mates, and convey differentiated information (Gil & Gahr 2002;Baker 2004;Nelson & Soha 2004;Beecher & Brenowitz 2005;Peake 2005). Concerted competitive displays, for instance in lekking species (Höglund & Alatalo 1995), synchronize breeding although these displays typically enable only a small proportion of the males involved to reproduce. ...
... Whereas sexual behaviour is exercised only by dominant individuals, parental care is also provided by helpers. Some evidence suggests that helpers are fully synchronous with the dominant pair but are kept from sexual behaviour by social mechanisms (Wingfield & Marler 1988;Ims 1990;Cockburn 1998;Wingfield & Silverin 2002;Baker 2004). Conspecific information transfer between colonial birds can create a 'culture' of timing. ...
Article
Timing is essential in seasonally changing habitats. Survival and reproduction are enhanced through precise adjustment to environmental conditions. Avian seasonal behaviour, that is, diverse activities associated with reproduction, moult and migration, has an endogenous basis and is ultimately linked to changes in environmental factors such as food supply. However, behaviour occurs in social contexts, and interactions with conspecifics are intimately linked to seasonal activities. Time programmes set the stage for social behaviour, which in turn fine-tunes seasonal activities. We propose that avian schedules are genuinely ‘sociable’: birds communicate seasonal behaviour by both intentional and inadvertent information transfer and negotiate it in competitive and cooperative interactions. Studying the interplay between seasonal and social behaviour can add to our understanding of animal behaviour, including mechanisms by which birds could cope with changing environmental conditions.
... A variety of these classification methods have been explored in the bioacoustics literature on a diversity of animal taxa, with varying feature sets and degrees of success (e.g. Fristrup & Watkins 1993;Kogan & Margoliash 1998;Baker 2004;Clemins et al. 2005). For example, Fristrup & Watkins (1993) correctly classified up to 85% of marine mammal sounds, Hayward (1997) 75% of marine mammal sounds, Kogan & Margoliash (1998) up to 97% of indigo bunting Passerina cyanea song units, Baker (2004) 96% of laughing kookaburra Dacelo novaeguineae breeding groups, Clemins et al. (2005) 82-94% of African elephant call types and Trifa, Kirschel & Taylor (2008) up to 99AE5% of antbird species songs. ...
... Fristrup & Watkins 1993;Kogan & Margoliash 1998;Baker 2004;Clemins et al. 2005). For example, Fristrup & Watkins (1993) correctly classified up to 85% of marine mammal sounds, Hayward (1997) 75% of marine mammal sounds, Kogan & Margoliash (1998) up to 97% of indigo bunting Passerina cyanea song units, Baker (2004) 96% of laughing kookaburra Dacelo novaeguineae breeding groups, Clemins et al. (2005) 82-94% of African elephant call types and Trifa, Kirschel & Taylor (2008) up to 99AE5% of antbird species songs. Kirschel et al. (2009) identified up to 99AE4% of Mexican antthrush individuals using three supervised-learning techniques (discriminant function analysis, fuzzy logic and hidden Markov models) and found that they all identified over 97% of recorded songs to the correct individual, despite high levels of rainforest background noise, though one unsupervised-learning method (self-organising maps) performed less well in classifying individuals. ...
Article
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1. Animals produce sounds for diverse biological functions such as defending territories, attracting mates, deterring predators, navigation, finding food and maintaining contact with members of their social group. Biologists can take advantage of these acoustic behaviours to gain valuable insights into the spatial and temporal scales over which individuals and populations interact. Advances in bioacoustic technology, including the development of autonomous cabled and wireless recording arrays, permit data collection at multiple locations over time. These systems are transforming the way we study individuals and populations of animals and are leading to significant advances in our understandings of the complex interactions between animals and their habitats.
... We cross-correlated these spectrograms, yielding a sym-metrical 47-by-47 correlation matrix containing 1081 unique pairwise peak correlation values. We also used SoundXT to perform principal coordinate analysis (PCO) on the interspecific correlation matrix to extract ordinated, independent measures (Gower, 1966;Legendre & Legendre, 1998;Cortopassi & Bradbury, 2000;Baker, 2004). These measures are useful for grouping sounds and associating sounds with extrinsic variables (Cortopassi & Bradbury, 2000;Baker, 2004). ...
... We also used SoundXT to perform principal coordinate analysis (PCO) on the interspecific correlation matrix to extract ordinated, independent measures (Gower, 1966;Legendre & Legendre, 1998;Cortopassi & Bradbury, 2000;Baker, 2004). These measures are useful for grouping sounds and associating sounds with extrinsic variables (Cortopassi & Bradbury, 2000;Baker, 2004). We retained principal coordinate axes based on plots of their eigenvalues ('scree-plots'), extracting axes with the largest eigenvalues (i.e. ...
Article
Flight calls are structurally simple avian vocalizations largely associated with sustained migratory flight. We used a multilocus phylogeny of 47 North American wood warblers (Aves: Parulidae) to quantify the extent of phylogenetic signal in flight-call spectrographic characteristics and to remove phylogenetic effects when testing for associations among flight-call attributes, behavioural characters related to migration strategies and ecological habitat variables. We also employed a quantile regression and null model approach to compare a matrix of interspecific phylogenetic divergence with indices of the corresponding acoustic differences derived from spectrographic measurements of flight calls. Nearly half of the measurements of flight-call properties exhibited significant associations with phylogeny. Controlling for phylogenetic effects, high-frequency flight calls were associated with species occupying taller and more open forest canopies. Ecological properties associated with migratory and winter distributions did not correlate with flight-call characteristics. Differences among the evolutionary histories of structural vs. signal properties of flightcalls suggest that phylogenetic and ecological effects are present. The evolution of flight-call syllable structure may involve selection for species recognition, whereas adaptation to the acoustic environment likely has influenced evolution of their spectral and temporal properties. More generally, the historical contribution to variation in behavioural characters is a long-standing source of debate; these results suggest that substantial phylogenetic effects may be present even in vocal traits that may be highly labile. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 155–173.
... To date, no indri research investigated whether acoustic properties of indri songs differ between groups. If differences occur between several neighboring groups in an area, it is possible that the song communicates group identity, not simply occupancy of an area (Baker, 2004(Baker, , 2009. ...
... A number of group-living bird and mammal species produce vocal choruses (e.g., Baker, 2004Baker, , 2009Bradley & Mennill, 2009;Harrington, 1989;Lehner, 1978;McComb et al., 1994;Mech, 1970;Pereira, Seeligson, & Macedonia, 1988;Seddon, 2002;Tenaza, 1976;Wiley & Wiley, 1977). In such species, more than two individuals are usually involved in producing a chorus, during which there may be some temporally distinct vocal units, and some overlapping vocal units. ...
Article
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The loud chorus songs of the group-living lemur Indri indri are a striking feature of rainforest areas of eastern Madagascar. Despite some research on the conspicuous vocal display of the indri, two hypotheses have not been addressed: do groups differ in the acoustic properties of their songs, and is there evidence of coordinated singing between individuals within groups. We recorded and analyzed the songs of three indri groups to examine these two questions. To answer the first question, we made quantitative spectral measures on songs of the three groups and performed multivariate analyses of the acoustic features of the notes constituting the songs. Our results showed songs of the three groups differed significantly, although there was overlap between groups. To answer the second question, we classified note types and quantified their occurrence as overlapping and abutting pairs. We found non-random associations between sequential note types in all three indri groups. These associations were consistent among groups, suggesting that individuals follow consistent answering rules when contributing to choruses. Whether indris use acoustic group identifiers in management of behavioral strategies and how within-group coordinated note production might function remain unknown. We compare our results to a number of taxonomically diverse species that live in groups and broadcast chorus and duet vocal signals.
... Social animals have complex vocal repertoires comprised of multiple call types that are used to communicate with each other in different contexts for different purposes, like location of group members, group reunion, territory advertisement, and coordinate their daily activity (Baker-Médard et al. 2013;Baker 2004;Bradbury and Vehrencamp 2011;Fichtel and Manser 2010;Lehner 1982;Mech 1970). Furthermore, the group members of some species emit vocalizations simultaneously, constituting group vocalizations or choruses (Foote et al. 2011;Harrington and Asa 2003). ...
Article
Wolf packs perform group vocalizations called chorus howls. These acoustic signals have a complex structure and could be involved in functions such as strengthening of social bonds, territory advertisement, or spacing between packs. We analyzed video recordings of 46 chorus howls emitted by 10 packs of wolves held in captivity, in order to investigate whether sex, age, social status, pack, or individual influence the way wolves participate in a chorus. We found that, during a chorus, wolves vocalized 63% of the time, with the howl being the most common vocalization (36% of the chorus duration), followed by woa (13.5%), other vocalizations (11.8%), and bark (1.7%). The main factor affecting the vocal behavior of wolves was age, since young wolves vocalized less and uttered shorter acoustic signals than adults. The discriminant analysis carried out with the wolves of Cañada Real pack assigned 89.3% of the cases to the correct individual, which is much better than the assignment expected by chance, suggesting that individuals could have a unique vocal usage during a chorus howl, mainly due to the use of howls and woa-woa howls. Based on our results, we propose that in the context of a chorus the woa-woa howl is important, although further research is needed to address this issue properly.
... A different relationship between distant neighbours may be found in populations of skylarks living in continuous habitats not subjected to high anthropization, where both syllable and sequence sharing are lower between neighbours and decrease with the distance between birds without distinct microdialects [10]. Further studies would be needed in other bird species showing similar group signatures as skylarks (e.g.26272829) to investigate if the group recognition process identified in our study is widespread in other songbird populations living in fragmented habitats. To distinguish among neighbours and strangers or among different neighbours, several cues have been suggested to be used by songbirds [3]: (1) repertoire composition (phonology); (2) order of production of repertoire components (syllable types or song types, i.e. syntax); (3) distinctive 'voice' characteristics and/or subtle differences in the song types versions of each individual [30,31]. ...
Article
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Discriminating threatening individuals from non-threatening ones allow territory owners to modulate their territorial responses according to the threat posed by each intruder. This ability reduces costs associated with territorial defence. Reduced aggression towards familiar adjacent neighbours, termed the dear-enemy effect, has been shown in numerous species. An important question that has never been investigated is whether territory owners perceive distant neighbours established in the same group as strangers because of their unfamiliarity, or as dear-enemies because of their group membership. To investigate this question, we played back to male skylarks (Alauda arvensis) songs of adjacent neighbours, distant neighbours established a few territories away in the same microdialect area and strangers. Additionally, we carried out a propagation experiment to investigate how far skylark songs are propagated in their natural habitat and we estimated repertoire similarity between adjacent neighbours, distant neighbours and strangers. We show that skylarks, in the field, respond less aggressively to songs of their distant and likely unfamiliar neighbours, as shown by the propagation experiment, compared to stranger songs. The song analysis revealed that individuals share a high amount of syllables and sequences with both their adjacent and distant neighbours, but only few syllables and no sequences with strangers. The observed reduction of aggression between distant neighbours thus probably results from their familiarity with the vocal group signature shared by all members of the neighbourhood. Therefore, in skylarks, dear-enemy-like relationships can be established between unfamiliar individuals who share a common acoustic code.
... Using playback experiments, several studies have shown that these coordinated territorial displays allow receivers to assess group size, coalition strength or sex ratio of the chorusing group (McComb, 1992;McComb et al., 1994;Seddon and Tobias, 2006;Hall and Magrath, 2007). In addition, acoustical analyses of these communal vocalizations have shown that the spectral parameters could also encode a group signature (Baker, 2004). ...
Article
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Colonies or communities of animals such as fishes, frogs, seabirds, or marine mammals can be noisy. Although vocal communication between clearly identified sender(s) and receiver(s) has been well studied, the properties of the noisy sound that results from the acoustic network of a colony of gregarious animals have received less attention. The resulting sound could nonetheless convey some information about the emitting group. Using custom-written software for automatic detection of vocalizations occurring over many hours of recordings, this study reports acoustic features of communal vocal activities in a gregarious species, the zebra finch (Taeniopygia guttata). By biasing the sex ratio and using two different housing conditions (individual versus communal housing), six groups of zebra finches were generated, with six different social structures that varied both in terms of sex-composition and proportion of paired individuals. The results showed that the rate of emission and the acoustic dynamic both depended on the social structure. In particular, the vocal activity of a group of zebra finches depended mainly on the number of unpaired birds, i.e., individuals not part of a stably bonded pair.
... There is strong evidence that chorusing functions as a cooperative behaviour in collaborative territory defence (e.g. laughing kookaburras, Dacelo novaeguineae: Reyer & Schmidl 1988; Baker 2004; Australian magpies, Gymnorhina tibicen: Brown & Farabaugh 1991 ; whitebrowed sparrow-weavers, Plocepasser mahali: Wingfield & Lewis 1993; subdesert mesites: Seddon 2002; black-breasted wood-quail, Odontophorus leucolaemus: Hale 2006) and in maintaining social bonds within the group (Australian magpies: Brown et al. 1988). Chorusing has also been suggested to function as a form of conflict between group members by mediating social hierarchies (e.g. ...
Article
Coordinated vocal displays of cooperatively breeding animals provide a compelling model for investigating the opposing motivations for engaging in conflict versus cooperative behaviours. Hypotheses for the function of coordinated vocal displays differ with respect to these motivations and have been traditionally investigated by using playback to simulate varying degrees of threat to individuals and groups. We evaluated the function of coordinated vocal displays by presenting territorial groups of cooperatively breeding rufous-naped wrens, Campylorhynchus rufinucha, with three playback stimuli: solos, duets and choruses. We found that all groups responded strongly to playback by approaching the loudspeaker together, vocalizing, and performing visual displays. A composite playback response measure showed significantly more aggressive reactions to all playback treatments compared to a preplayback control period, yet did not vary across solo, duet and chorus treatments. This suggests that the playback stimuli represented equally strong threats despite the varying numbers of contributors to each stimulus, and does not support the hypothesis that coordinated vocalizations are graded signals of threat in this species. Our findings stand in contrast to previous playback studies that have reported an increase in aggression with an increasing number of simulated intruders, or an increase in coordinated vocalizations in response to solo playback. We interpret the results of our study as evidence that coordinated vocalizations function in the cooperative behaviour of joint territory defence in the rufous-naped wren.
... Duetting could encode additional kinds of information that may be functional in the context of the behavioral transactions involving 'assessment and management' (Owings & Morton 1998) within mated pairs and between neighboring pairs (Langmore 1998;Hall 2000Hall , 2004Mann et al. 2003;Logue & Gammon 2004;Logue 2006Logue , 2007. Yet, other species exhibit a social system that may include not only mated pairs but also groups of larger size, and these groups produce a chorus type of song (Brown et al. 1988;Reyer & Schmidl 1988;Seddon 2002;Baker 2004). ...
Article
Songs of birds encode several kinds of information that may be used during interactions with conspecifics. Some bird species live in social groups and perform territorial advertisement song as a group. Group singing raises questions concerning its function in the social life of the group. Australian magpies (Cracticus tibicen = Gymnorhina tibicen) are group-living birds that sing chorus songs known as carols. Each carol is composed of a series of individual syllables. Previous spectrographic descriptions of carols in eastern Australian populations found individual-specific and sex-specific acoustic characteristics in carol syllables and group-specific characteristics in carol songs. These findings suggest that carols might reveal not only the identity of the group, but also other properties, such as its size and sex composition, which could influence outcomes in assessment/management interactions between groups. I tape-recorded and analyzed carols of seven magpie groups in Western Australia, a location and subspecies (C. t. dorsalis) differing from the previous studies of singing by magpies. I analyzed carols of each group to determine acoustic features of syllables, syllable syntax within carols and the way carols are delivered as a repertoire. Visual classification of individual song syllables as seen on sound spectrograms, automated quantification of spectral features of song syllables, examination for carol repertoires and call-answer syntax within carols all revealed little evidence that magpies have individual-specific or group-specific vocal characteristics. Thus, chorus songs do not appear sufficiently distinctive to communicate identity at the level of the group nor reveal group size and composition. Instead, caroling may signal only territory occupancy and willingness to participate in territorial defense. A new hypothesis is advanced suggesting that chorus songs of group-living birds are an unselected consequence of the coordinated duet songs of the breeding male and female whose duets are joined adventitiously by other group members.
... Chorusing, the production of coordinated vocal displays by more than two individuals in group living birds and mammals, has received less attention than duetting, but it is likely to have functions that are similar to duets. There is good evidence that chorusing is involved in the collaborative maintenance of territories (e.g., laughing kookaburras, Dacelo novaeguineae, Reyer & Schmidl, 1988;Baker, 2004; Australian magpies, Gymnorhina tibicen, Brown & Farabaugh, 1991; whitebrowed sparrow-weavers, Plocepasser mahali, Wingfield & Lewis, 1993; female lions, Panthera leo, McComb et al., 1994; subdesert mesites, Monias benschi, Seddon, 2002). Chorusing is also likely to function in intra-group cohesion (Payne, 1971;Brown et al., 1988) and the establishment and maintenance of dominance hierarchies among group members (Reyer & Schmidl, 1988). ...
Article
Black-breasted wood-quail (Odontophorus leucolaemus) are vocal, group living birds (covey size ranges from 2 to 15 individuals) that inhabit the dense understory of highland forest in Costa Rica. Mated pairs produce coordinated duets and groups produce coordinated choruses that are audible to humans from a distance of at least 200 m. Duets and choruses are antiphonal; they consist of two syllables that are comprised of two elements each, which are repeated over and over in an alternating fashion. Neighbouring coveys are most often heard calling back and forth just after dawn and all group members participate in singing and territory defence. During territorial encounters, group singing is often accompanied by displays, chases, and even physical fights between members of opposing coveys. Black-breasted wood-quail produce at least five structurally distinct close-range calls that are associated with within-group communication and territorial encounters. Observations of the context of unprovoked duets and choruses, in addition to responses to simulated territorial intrusion using playback, indicate that these songs play an important role in territory advertisement and defence. Furthermore, black-breasted wood-quail may adjust their response to playback as a function of relative group size, suggesting that choruses could function in relative numerical assessment of group size.
... Some species produce acoustic territorial signals with an individual signature (Marler and Hobbett 1975; Reby et al. 1999; Bee and Gerhardt 2001; Frommolt et al. 2003; Tripovich et al. 2005) that could facilitate individual recognition among rivals. For species which defend their territory as group or family, a vocal signature encoding group or family affiliation is advantageous (birds: Brown and Farabough 1997; Baker 2004; Radford 2005). In mammals, studies on group-specific vocal signatures in territorial signals are rare, even though several species have been found to defend their territory acoustically as a group (e.g., lions, wolves, howler monkeys). ...
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Acoustic territorial displays are common among birds but comparatively rare among mammals. An exceptionallyvocal mammal well-known for its elaborate territorial displays is the polygynous greater sac-winged bat, Saccopteryx bilineata. Male S. bilineata are often philopatric and establish small territories in their birth colony in which females can roost during the day. During territorial defense, males produce complex territorial songs that are learned through vocal imitation. Territorial songs are mainly produced at dawn and dusk. We studied social influences on male vocal activity and the occurrence of vocal signatures in territorial songs of 27 male S. bilineata from 12 differentsized colonies in Panama. Males produced significantly more territorial songs when they had more territorial neighbors or when they had females roosting in their territories, indicating that male vocal activity rises with increasing male–male competition. Territorial songs are multisyllabic vocalizations with low-frequency buzz syllables being most prominent. We found statistical evidence for a pronounced individual signature encoded in the buzz syllables of territorial songs that could facilitate individual recognition among rival neighbors. Additionally, we found a vocal group signature in territorial songs, suggesting that young males may learn territorial songs from more than one tutor male. Resident male S. bilineata appear to cooperatively defend their colony against male intruders, making a group signature in territorial songs potentially advantageous.
... Individual vocal features have been recognized in a large variety of taxa, from birds (PEAKE et al. 1999) to several mammalian species, including canids (DURBIN 1998;DARDEN et al. 2003;FROMMOLT et al. 2003;HARTWIG 2005). It was recently shown that it was possible to distinguish individuals within a group of conspecifics by virtue of their vocalizations both in birds (BAKER 2004;RADFORD 2005) and in mammals (BOUGHMAN 1997;CROCKFORD et al. 2004;TOWNSEND et al. 2010). No research has yet addressed the potential for group-specific differences, especially in the wild. ...
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Acoustic communication conveys a variety of information that is a helpful tool for animal conservation. The wolf is an elusive species, which can be detected through the howls that individuals emit. In this study we investigated the acoustic features of wild wolf pack howls from five locations in the province of Arezzo, Italy. We tested the hypothesis that each group had a distinctive vocal signature. Our results showed that these wolf packs emitted howls with significantly distinctive acoustic structures. We hypothesized that group-specific vocal signatures require temporal stability to be functional. Indeed, we did not find any statistical differences in howls collected from the same location during the same season or for 2 consecutive years. We suggest that the acoustic features of howls can be used to distinguish wolf packs in the wild.
... In social species vocal signals are commonly found to not only serve communication within, but also between groups, and call usage and structure frequently change with the social context ͑e.g., Elowson and Snowdon, 1994;Smolker and Pepper, 1999;Hopp et al., 2001;Snowdon and de la Torre, 2002;Baker, 2004;Radford, 2005͒. Group size and composition are known to affect the use of stereotyped calls in several highly social species, e.g., African elephants ͑Payne et al., 2003͒ andNorthern right whales ͑Parks and. ...
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Vocal communication within and between groups of individuals has been described extensively in birds and terrestrial mammals, however, little is known about how cetaceans utilize their sounds in their natural environment. Resident killer whales, Orcinus orca, live in highly stable matrilines and exhibit group-specific vocal dialects. Single call types cannot exclusively be associated with particular behaviors and calls are thought to function in group identification and intragroup communication. In the present study call usage of three closely related matrilines of the Northern resident community was compared in various intra- and intergroup contexts. In two out of the three matrilines significant changes in vocal behavior depending both on the presence and identity of accompanying whales were found. Most evidently, family-specific call subtypes, as well as aberrant and variable calls, were emitted at higher rates, whereas "low arousal" call types were used less in the presence of matrilines from different pods, subclans, or clans. Ways in which the observed changes may function both in intra- and intergroup communication.
... We did not identify units separated by a silent gap that was longer than unit duration as constituting a series. We indicated as 'harsh' sounds (see FISCHER & HAMMERSCHMIDT 2002;BAKER 2004) those vocal types showing a remarkable amount of broadband noise (FITCH et al. 2002). ...
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We recorded vocalisations of wild Eulemur mongoz groups in Madagascar and the Comoros Islands, as well as from habituated captive groups housed in European and Madagascan zoos. Each vocalisation was quantitatively described by means of an acoustic analysis procedure implemented in Praat, and vocal types were distinguished both by ear and by the visual screening of spectrograms. Vocal signals were then associated with the context in which they were produced, to explore whether they occur only in specific behavioural contexts or are uttered in a range of situations. We found that mongoose lemurs possess highly context-specific aerial alarm calls and territorial calls, while the ‘croui-croui’ is usually emitted to communicate between individuals regrouping at sunset. The other calls we recorded, such as those including low-pitched pulse trains sometimes followed by harmonic elements, were not tightly associated with a particular context. Mongoose lemur utterances included calls produced with closed mouths and the involvement of nasal resonance, or with constant degrees of mouth opening or mandible ‘articulation’ during phonation. We observed 15 vocal types, nine of which were entered into a multivariate model that classified vocal types with a high degree of reliability. The second and third formants played an important role in discriminating among types of calls.
... During duets, pairs vocalize with temporal coordination to produce a more or less stereotyped acoustic pattern (Farabaugh, 1982;Kovach et al., 2014). For species exhibiting a social system that includes multiple sexually mature adults (i.e., group-living species), all individuals in the group may produce a song together, known 1as a chorus (Baker, 2004;Golabek et al., 2012;Seddon, 2002). In some species, females sing more than males, but such cases are rarely noted in the literature. ...
Article
Birdsong is a particularly useful model for animal communication studies. However, current knowledge is derived mainly from the study of male song, and is therefore incomplete. Here, we investigated whether singing behaviour differs between sexes in the cooperatively breeding Western Australian magpie (Gymnorhina tibicen dorsalis). This subspecies lives in territorial groups, and in our population there is a female-biased sex ratio, which may lead to a high level of female-female competition for males. Observations of 94 magpies (54 females, 40 males) revealed that females sang more often than males. As bird song is a sexually multidimensional signal, we also studied amplitude and structure of the main territorial high-amplitude song in magpie; the carol. We found that females sing at the same amplitude as males, but that male and female carols exhibit differences in frequency. These results highlight the importance of studying female song and may change our perception regarding the evolution of sex-specific traits, given the primary focus on male singing as a sexually selected trait in the literature to date. The next step is to discover additional species in which females sing more than males in order to improve our currently incomplete understanding of the evolution of bird song.
... In such instances, the adults fly to an exposed position in a tree, on a roof top, overhead wires, TV antennas (see Figure 12). As in kookaburras [34], such family group gatherings occur after the successful eviction of an intruder or a bird of prey. A group chorus of magpies may well be amongst the loudest of any land animals ( Figure 6). ...
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Young territorial songbirds have calls to learn, especially calls that may be vital for maintaining territory. Territoriality is largely reinforced and communicated by vocal signals. In their natal territory, juvenile magpies (Gymnorhina tibicen) enjoy protection from predators for 8–9 months. It is not at all clear, however, when and how a young territorial songbird learns to distinguish the meaning of calls and songs expressed by parents, conspecifics, neighbours, and heterospecifics, or how territorial calls are incorporated into the juvenile’s own repertoire. This project investigated acquisition and expression of the vocal repertoire in juvenile magpies and assessed the responses of adults and juveniles to playbacks of neighbour and stranger calls inside their territory. The results reported here identify age of appearance of specific vocalisations and the limits of their expression in juveniles. One new and surprising result was that many types of adult vocalisation were not voiced by juveniles. Playbacks of calls of neighbours and strangers inside the natal territory further established that adults responded strongly but differentially to neighbours versus strangers. By contrast, juveniles needed months before paying any attention to and distinguishing between neighbour and stranger calls and eventually did so only in non-vocal ways (such as referral to adults). These results provide evidence that auditory perception not only includes recognition and memory of neighbour calls but also an assessment of the importance of such calls in the context of territoriality.
... Oscines in the tropics exhibit several vocal behaviours that are rare or absent in the north temperate zone, including female solo songs (Langmore 1998;Beecher and Brenowitz 2005), duets (Hall 2004(Hall , 2009, and choruses (e.g. Baker 2004Baker , 2009Hale 2006). ...
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There are relatively few quantitative descriptive studies of the vocalisations and vocal behaviour of tropical bird species, in spite of the tropic’s rich avian biodiversity and the extensive variety of vocalisations produced by tropical birds. This lack of information inhibits our understanding of tropical animals, including our ability to perform comparative analyses on vocal behaviours from an evolutionary perspective. In this study, we present the first quantitative description of the vocal repertoire and daily vocal activity of White-eared Ground-sparrows (Melozone leucotis), using focal and autonomous recordings collected during two consecutive breeding seasons in Costa Rica. We classified vocalisations into categories based on their visual appearance on sound spectrograms to create a library of vocalisations for this species. We found that White-eared Ground-sparrows produce three main categories of vocalisations: solo songs, calls, and duets. Solo songs were produced only by males. Each male sang a repertoire of solo song types, which all shared the same general structure with short introductory notes, a frequency-modulated middle section, and a terminal trill. Both sexes produce calls and coordinated vocal duets. We quantified patterns of diel variation in each category of vocalisation, and found that the Ground-sparrows produced all three vocalisations at higher output at dawn (between 0500 and 0600 hours) compared to the rest of the day. This study allowed us to conduct the first comparisons of vocalisations between White-eared Ground-sparrows and North American species in the genus Melozone, and revealed both similarities and differences between the species groups. Our investigation also showed that vocalisations related to communication within pairs and to territory defence (calls and duets) exhibited lower levels of individual distinctiveness than vocalisations related mainly to female attraction (male solo songs). Our observations suggest that each of the three types of vocalisations have multiple functions in White-eared Ground-sparrows, revealing diverse communication functions with a small vocal repertoire in this tropical songbird.
... We did not identify units separated by a silent gap that was longer than unit duration as constituting a series. We indicated as 'harsh' sounds (see FISCHER & HAMMERSCHMIDT 2002;BAKER 2004) those vocal types showing a remarkable amount of broadband noise (FITCH et al. 2002). ...
... However, Hallberg (2007) considered assessments of coyote chorus size fairly accurate because mean differences between actual chorus size and human estimations were within one or two individuals. In other species that also emit chorus vocalizations, such as laughing kookaburras (Dacelo novaeguineae), determining by ear the number of individuals participating in a chorus is considered an impossible task (Baker 2004). ...
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Management decision-making processes require reliable tools providing information on the distribution, abundance, and trend of populations. Wolves vocalize in response to human imitations of howls. Traditionally, this phenomenon has been the basis of a widespread monitoring tool to assess the reproductive status in a wolf pack, as well as to estimate the minimum number of individuals in the pack: the elicited vocalization technique. However, despite its broad use, only a few attempts to quantify its accuracy have been made so far. Here, we carried out a test to evaluate the accuracy of estimates obtained from the elicited-vocalization technique. We administered "chorus tests" to 205 human subjects, 182 rangers —with different level of experience with wolves— and 23 subjects with no previous experience with the species. We found that the estimates of the number of wolves participating in a chorus were not accurate, regardless of the experience of the listener (the correct number of wolves was only determined in 32% of tests). Listeners, however, identified pups vocalizing 98% of the times when there were pups in the chorus. They also reported the presence of pups when they were not present with a high frequency (71%). Estimating the number of individuals by the unaided human ear is flawed because of the bias inherent in the elicited-vocalization technique. Howling surveys have a low degree of selectivity to confirm the presence of pups. Thus, we make recommendations to improve the elicited-vocalization technique as a tool to monitor the presence of pups.
... Intruder neighbor-stranger identity could be discerned through a range of sensory modalities, including sound and smell (Radford 2005;Müller and Manser 2007). For instance, group members of many social bird species combine in the production of vocal choruses, which can have distinctive groupspecific signatures (Baker 2004;Radford 2005). Playback experiments have demonstrated that territory-holders can distinguish both between neighbors and strangers and between different neighbors based solely on these acoustic cues (Radford 2005 Immediate behavioral reactions to intruders or to evidence of their recent presence (e.g., scent marks). ...
Article
Territorial behavior is widespread throughout the animal kingdom, with responses to conspecific intruders differing depending on various ecological, life history, and social factors. One factor which has received considerable research attention is rival identity. Early work provided many examples of species exhibiting relatively stronger responses to strangers versus neighbors (the "dear-enemy" effect) or the opposite (the "nasty-neighbor" effect). However, those studies focused predominantly on single or pair-bonded territory-holders. There is increasing evidence of neighbor-stranger response differences in group-living species (where 3 or more individuals share a territory), and of within-species variation in the relative responses shown to these 2 intruder types. Considering social species is important both because group territoriality is widespread and because group responses include the actions of multiple individuals whose interests and motivations differ. We begin our review with a summary of territoriality in group-living species. We then discuss causes of variation in territorial responses depending on intruder neighbor-stranger identity, considering both between-species differences and those within species arising from context-dependent variation and from individual group members responding differently to the same intrusion. We next detail the consequences of different territorial responses, in terms of both postinteraction behavior and individual benefits and costs. Finally, we suggest 3 key areas - theoretical modeling, hormonal mechanisms, and anthropogenic disturbances - that could be developed when considering the relative responses of territory-holders to neighbors and strangers. Since conflict is a powerful selective force, determining the causes and consequences of variation in group-territorial behavior is important for a full understanding of sociality.
... Correspondingly, the functions of vocal group signatures in other group-living territorial animals are also related to territorial maintenance and resource defence (e.g., lions [57], hyenas [22], African wild dogs [20], coyotes [21], and wolves [58][59]). Group chorusing may encode group identity (wolves [14], laughing kookaburras [12], green woodhoopoes [13]; but see Australian magpies [62]) and signal group size (lions [63], red howler monkeys [64], grreen woodhoopoes [65]; but see wolves [66]). Wolves and lions use their group calls to actively avoid agonistic encounters [57,59], whereas hyenas and African wild dogs also emit choruses during confrontations with other groups [20,22]. ...
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Group living animals often engage in corporate territorial defence. Territorial group vocalizations can provide information about group identity, size and composition. Neighbouring groups may use this information to avoid unfavourable direct conflicts. Giant otters are highly social and territorial animals with an elaborate vocal repertoire. They produce long-range screams when they are alert or excited, i.e. in an alarm, isolation or begging context. Long-range screams are not only produced by one individual at a time (‘single screams’) but also by multiple group members simultaneously, resulting in a highly conspicuous ‘group chorus’. Wild giant otters regularly produce group choruses during interactions with predators, when they detect intruders in their territory or before group reunions after separation. Since single screams and especially group choruses probably contribute to the groups’ corporate territorial defence, we hypothesized that group identity is encoded in single screams and group choruses. We analysed vocalizations from five wild and three captive giant otter groups and found statistical evidence for a group signature in group choruses. Results for single screams were less conclusive, which might have been caused by the comparatively lower sample size. We suggest that giant otters may gain information on group identity by listening to group choruses. Group identity likely constitutes important social information for giant otters since territory boundaries of neighbouring groups can overlap and direct inter-group conflicts are severe. Therefore, group chorusing may contribute to the mutual avoidance of members from different groups.
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Avian duetting is an unusual but taxonomically widespread phenomenon, occurring in over 400 species, representing 40% of bird families. Duets vary in form from loosely overlapping songs to highly coordinated duets where paired birds both adjust the timing and type of phrases they sing to fit those of their partner over the course of the duet. Duet coordination therefore signals how attentive an individual is to its partner, both to the partner and to other listeners. While some aspects of duetting are poorly understood, such as its ontogeny and causation (including hormonal and neural bases), it is clear that duetting serves multiple functions, including maintaining the year-round territories and partnerships that characterize many duetting species.
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In many animal species, chiefly birds and some marine mammals, the repertoire of acoustic communication signals represents learned features of the behavioural phenotype, acquired and transmitted across generations as cultural traditions. These signals often are found to vary spatially among sub-species or local populations (e.g., dialects), as well as among smaller social groupings (colonies, flocks, pods, clans). Moreover, within the whole repertoire of different vocal signals of a species there can be differences in the patterns of spatial variation from one type of vocalization to another. A previous study of birdsong, for example, showed that males had two different kinds of song, functionally differing and with discordant patterns of geographic variation. This, and other studies describing spatial distributions of different elements of a learned vocal repertoire, suggests a general hypothesis that functional differences among an ensemble of cultural traits may be manifest as differences in spatial variation. My extension of this hypothesis is that among such a suite of cultural traits those of similar function will tend to co-vary spatially. In this report, I use three vocalizations of a parrot species to test this hypothesis. I recorded vocalizations of the Australian ringneck (Platycercus (= Barnardius) zonarius), at 49 sites across three subspecies distributions and quantified variation in the acoustic features of their vocal signals. Two of the vocal signals have similar function and, according to the hypothesis, should follow similar patterns of spatial variation, whereas the third signal has a differing function and is not expected to vary spatially in concordance with the other two signals. These predicted patterns were substantially upheld.
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In this paper we propose a method that uses the averaged Mel-frequency cepstral coefficients (MFCCs) and linear discriminant analysis (LDA) to automatically identify animals from their sounds. First, each syllable corresponding to a piece of vocalization is segmented. The averaged MFCCs over all frames in a syllable are calculated as the vocalization features. Linear discriminant analysis (LDA), which finds out a transformation matrix that minimizes the within-class distance and maximizes the between-class distance, is utilized to increase the classification accuracy while to reduce the dimensionality of the feature vectors. In our experiment, the average classification accuracy is 96.8% and 98.1% for 30 kinds of frog calls and 19 kinds of cricket calls, respectively.
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Flight calls are commonly produced by nocturnal migrant birds. Uncertain or unknown identities and lack of information about inter- and intraspecific variation in call notes limit the usefulness of flight calls in monitoring bird Populations. We developed a novel method for recording flight calls of temporarily captive birds that allows us to study inter- and intraspecific variation in call notes of birds of known identity, age, and sex. We recorded calls and analyzed data from 13,271 flight calls recorded from 469 individuals of 28 warbler species (Parulidae) over a two-year period. Principal coordinate ordination of spectral cross-correlation data on 7 of the 28 species indicated that flight calls recorded in captivity are similar to those recorded from wild birds. Visual and aural comparisons of species' flight calls from these two different types of recordings support these results. Additionally, we verified flight calls previously identified primarily on inferential evidence and report on previously Undocumented flight calls. This method quickly provides many high-quality recordings of the flight calls of individuals of known age and sex, and the results Of Our analyses greatly facilitate the development of automated sound-analysis algorithms critical for implementing and strengthening future acoustic monitoring applications. Received 22 September 2008, accepted 16 January 2009.
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We investigated whether vocal communication in wild Large-billed Crows (Corvus macrorhynchos) is governed by a temporal rule as an evidence for vocal exchange. In order to examine this potential temporal rule, we analyzed the intervals between two single-note ka calls produced sequentially by two crows in gregarious situations. Two different individuals sequentially uttered ka calls at approximately 0.2–0.8-sec intervals, Such a specific time window was not observed in a simulation of ‘imaginary’ flocks, in which multiple crows independently emitted ka calls at their own pace, similar to the calls of solitary crows in the wild. These results suggest that the specific time window of inter-call intervals between different crows is not an incidental phenomenon in a crowded situation, but rather a specific event that follows a temporal rule organizing vocal communication of two crows. Our findings provide the first evidence of vocal exchange using ka calls that are organized following a precise temporal pattern in Large-billed Crows.
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Vocal communication in duetting and chorusing birds is a growing area of study in avian ecology, yet much remains unknown about temporal and population-level variation in these complex vocal signals. In this study, we describe the acoustic structure and temporal variation in solos, duets, and choruses in the Rufous-naped Wren (Campylorhynchus rufinucha), a cooperatively breeding neotropical passerine. We collected focal recordings of 19 groups to assess both diel and seasonal variation in vocal output, as well as population-wide sharing of vocal signals. We found that birds produce a complex array of vocalisations, including tonal, frequency-modulated syllables grouped into phrases, as well as stereotyped, atonal sounds. Songs are produced as solos or combined into duets and choruses. Solo and duet songs show a dawn chorus effect. Solo song rate, but not duet or chorus rate, varied across breeding stages. The majority of phrases are shared amongst groups, significantly more amongst groups in nearby territories. We suggest that chorus songs may be an important indicator of group identity and may play a role in maintaining group territories, but do not play a role in relation to the breeding cycle. The degree of population-wide phrase-sharing suggests either short-distance dispersal or delayed song learning. This paper is the first fine-scale description of vocal behaviour in this species and enhances our understanding of group-singing in a complex social environment.
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Singing is a complex form of communicating, incorporating two classes of signaling specializations with distinctive properties: primary signal units, and formal rules governing sequential order in sustained performances. The properties of each class enable it to provide its own characteristic kinds of information. As a fundamental procedure used in a wide range of circumstances, singing has many functions and is a major part of the communication of an enormous spectrum of animals. Yet recognition of singing's breadth and informative potential is commonly obscured by involved and inadequate definitions and use of one term, “song”, to cover both the components of singing and the formal sequencing rules. A simple, operationally defined distinction between sustained performances and their components is proposed herein, and its implications are examined.Sustained orderly singing performances are particularly useful for communicating at a distance, often obviating closer encounters. None the less, because singing provides information continuously it can also operate in close, nearly stable interactions (rapidly changing events disrupt or preclude singing). Each component signal of a performance usually provides information about a singer's identity, location and behavior, and different components can provide different information about behavior. The pattern in which the components are sung can reveal relative probabilities of different actions and the rates and directions of changes in those probabilities. The elaboration of singing that provides such information cannot be explained simply as a result of sexual selection or other postulates that assume almost total redundancy of components.Contrary to many existing definitions, singing is not limited by complexity of component form, the gender or age of performers, or season. It functions much more widely than is generally understood, for example, in parent-offspring interactions, mobbing, and vigilance behavior. Much singing that goes unrecognized because it incorporates signal units that are not “songs” is revealed by distinguishing between the properties of sustained performances and the very different properties of their components. Even non-vocal signaling sequences can be formally similar to singing.
Chapter
What are the genetic consequences of dispersal? This is a question which includes many controversial components. Does environmental heterogeneity maintain genetic variation, and if so, how does dispersal interact with this heterogeneity to affect levels of variability? Does gene flow bind a species together into a homogeneous unit, or can adaptation and divergence occur despite free intermingling? Do genetic factors, such as levels of inbreeding, or of variability, determine the evolution of dispersal itself? Several chapters in this book (e.g. Chapters 1, 4, 5 and 9) consider this question. This chapter therefore concentrates on the effects of environmental heterogeneity and gene flow on patterns of genetic variation, rather than on the evolution of dispersal itself; examples are drawn from a wide variety of taxa.
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Laughing Kookaburras Dacelo novaeguineae combine a conspicuous group vocalisation with a social structure in which subordinate helpers assist a dominant breeding pair in raising young. The structural and temporal characteristics of the laugh song in captivity and in the field were related to spatial distribution of group members, to social interactions within and between groups and to group size and territory size. Under all conditions, group songs lasted longer than pair songs and contained a higher proportion of the loudest element, the actual laugh part. Other parameters of song structure did not differ either with group composition or context. Joint songs fell into two categories: those during the day, (usually involving the breeding pair only); and those at the roost during dusk and dawn, usually involving all group members, i.e. the pair plus one to three helpers. Songs without the breeding pair or with only one member of it were rare. The spatial distribution of group members during singing was almost identical to that when not singing, but differed from a random distribution. Songs at the roost amounted to about 60% of all songs produced and shifted with the times of sunrise and sunset. At dusk, song frequency was mainly determined by group size and at dawn mainly by the total number of neighbours. During daytime, singing was usually connected with inter- and intra-group disputes. We conclude that the Kookaburras's laugh song signals aggression and aids in (a) defending a temtory, (b) guarding the mate and (c) establishing and maintaining a dominance hierarchy between breeders and helpers. In this last context (c) helper singing, especially during daytime, indicates a challenge to a breeder's status.
Article
We explore the effectiveness of spectrographs cross-correlation (SPCC) combined with principal coordinates (PCO) analysis as a method for sound comparison. We do this using synthetic sounds modeled after the individually-distinctive, harmonically-rich contact calls of wild orange-fronted conures Aratinga canicularis. Calls with acoustic properties similar to Aratinga contact calls are common in other taxa including non-oscine birds, primates and cetaceans. We generated signals with known variations in time-frequency pattern, duration, noise level, harmonic content and harmonic weighting, and applied SPCC-PCO analysis to obtain an ordering of sounds in n-dimensional space. We find that shared time-frequency patterns dominate the positioning of sounds in PCO space. This was true despite high variability in signal-to-noise ratio (from −60 to +40 dB) and duration (150–275 ms). Furthermore, inclusion of naturally-weighted harmonics (versus fundamentals only) enhances, rather than obscures, the separation of call types. We conclude that SPCC-PCO is an effective method for sorting sounds based on overall time-frequency pattern. In addition, the resulting PCO measures can be used in statistical tests of association with extrinsic variables. The method is thus an effective starting point for examining most bioacoustic hypotheses.
Article
In macaques and baboons, scream vocalizations play a major role in the recruitment of allies against agonistic opponents. Pigtail macaques make use of 4 acoustically distinct scream types, with each associated with a particular agonistic context (defined in terms of the opponent's relative dominance rank and the intensity of the aggression). Information about caller identity must also be encoded in recruitment screams if spatially distant allies are to make decisions about intervention. In this study, the agonistic screams of pigtail macaques were analyzed for evidence of vocal signatures that may serve to identify matrilineal kin groups. Maternal genealogical relationships were known for all individuals in the 56 member study group. Direct discriminant analysis was used to classify calls of individuals on the basis of their acoustic structure to one of 3 groups defined by matrilineal relatedness (two homogeneous groups, or matrilines, and one heterogeneous control group). Two scream types associated with higher-ranking opponents were analyzed separately: contact aggression screams and noncontact screams. A highly significant proportion of calls was classified to the correct matrilineal group for both scream classes. The acoustic basis for matrilineal vocal signatures in these calls apparently exists. Efficient vocal communication may require monkeys to classify group members at different levels, depending upon the degree of specificity needed.
Article
Kin and nonkin cooperative groups exist in the same population. Results include description of song, song repertories, syllable repertories, repertoire sharing in groups, and syllable sharing and vocal imitation in a tame magpie. -from Authors
Article
We describe and illustrate with sonograms the loud calls of a monogamous, territorial ape, the lar gibbon (Hylobates lar). We attempt an overview of its repertoire of loud calls, their organisation, contexts and functions. The description is based on a two year study of a wild population in Khao Yai National Park, Thailand. We distinguish seven classes of call bout: male solo, male dispute calls, female solo, normal duet by bonded pair, ooaa duet (similar to normal duet, but more infectious to other groups), disturbed calls and contact calls. The organisation of the normal duet is described in detail, showing the coordination of the sexes, the development of the male part through the call bout, and the presence of individual and pair differences. The discussion considers the possible functions of duets, of male solos, and of disturbed calls given in reaction to man.
Article
Although the howlers roared in a variety of contexts, at least 94.2% of daytime roars by each study troop were directed at nearly visible monkeys, in particular at solitary individuals and at neighbouring troops. Males who had no competitors within the troop had significantly higher daily roaring rates than males who had competitors within the troop. During inter-troop encounters, males in troops with a smaller number of males called significantly more than did males accompanied by more males. The loud roars of red howler monkeys are thus used in assessment of their opponents, as an alternative to energetically expensive chases and fights. The main function of the red howler male roar may be to repel solitary males and subordinate males in neighbouring troops who may attempt to replace them. -from Author
Article
The social behaviour of many species of non-human primates suggests a capacity for both individual and kin recognition. In these species, the ability to signal and perceive identity at a distance may be an important adaptation facilitating intra-group social communication. Variation in vocalizations is hypothesized to provide a basis for this ability. Playback experiments were conducted to test for vocal recognition of contact calls between adult female rhesus macaques,Macaca mulatta. Single-trial playbacks of the contact call of either a matrilineal relative or a familiar, non-relative group member were used to test for discrimination of kin from non-kin. Females responded significantly faster and longer to the contact calls of matrilineal relatives. A habituation–discrimination paradigm was then used to test for individual recognition. Females habituated to successive presentations of different exemplars of the contact calls of one matrilineal relative, then showed a significant rebound in response to the subsequent presentation of a contact call from a second matrilineal relative. These results indicate an ability for vocal recognition of both individuals and kin. Females' responses to playbacks suggested the additional possibility for categorical recognition of matrilineal kinship, or its correlates.
Article
This paper reports a study of the bioacoustics and locomotor behaviours of siamang (Hylobates syndactylus) during calling. Ten call bouts were videotaped and analysed in detail. The results suggest that the calls are complex duets produced sequentially, and that they are interactively organized by means of co-ordinating cues. The relationship between vocal and non-vocal behaviours, and the spacing of the duetting animals, are also organized in a regular fashion. The advantages and importance of videotaping over other methods in the micro-analysis of these calls are stressed.
Article
Unlike nonhuman primates and some other species used in attempts to condition vocal behavior, certain song birds display considerable facility at vocal imitation in the wild state. Species-specific characteristics of the song of the male white-crowned sparrow are normally acquired by learning from adults. Local song dialects result. Males raised in individual or group isolation developed abnormal songs. Exposure to normal song during a critical period of 10-50 days of age resulted in normal song development and in reproduction of the particular training dialect. Exposure to normal song during the 50-100 day age period shifted subsequent song development in a normal direction, but details of the training song were not reproduced. Exposure before 10 days and after 100 days of age had no effect. Song learning is selective in that exposure to songs of other species of 10-50 days of age had no effect on song development. Sensory rather than motor constraints appear to be responsible for the selectivity. To explain song development, an auditory template is postulated. At the start of the critical period the template is only a crude specification of normal song, but sufficient to exclude songs of other species. In training the specifications of the template become more precise. Vocalizations are matched to the template subsequently by auditory feedback. No extrinsic reinforcement seems to be necessary. Several analogies are drawn between song learning in white-crowned sparrows and speech development in children. (65 ref.) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Sensitive periods for song acquisition by male swamp sparrows in the first year of life were compared, using two types of training protocol: 1) training with tape-recorded songs and, 2) training by exposure to live singing tutors. Subjects were exposed to a range of tutors and tape recordings on regularly changing schedules. Singing was recorded, and the time of acquisition was determined by the occurrence of imitations of particular models. The results obtained with tape- and live-tutoring were very similar. In both cases most learning occurred prior to 45–55 days of age. Some song acquisition occurred as late as 250–300 days of age.
Article
Cultural innovations are commonly noted in animals, but times of development of novel traits are usually unknown. We report here a novel song type arising in a bird population on an offshore island of Western Australia where the time of colonization of the island by the Western Gerygone Gerygone fusca is known. On the mainland, a single song type is widespread. On Rottnest Island, many individuals sing a different type of song and a number possess a repertoire of two song types: the standard song shared with the mainland and the novel song type not found on the neighbouring mainland. The novel song type found on Rottnest is so different in its syntactical structure that one could easily mistake it for that of a new species. The characteristic song of mainland birds is irregular in the frequencies at which the notes within a song are delivered. The novel song on Rottnest has a highly structured syntax with notes delivered at a strict and repeated sequence of frequencies resulting in a rhythmic musical sound. The species is known to have colonized Rottnest in about 1955. The new song type apparently developed rapidly by cultural evolution in the last 50 years.
Article
In this study of songs of the singing honeyeater, Meliphaga virescens, we examined the consequences of isolation on the meme pool of syllables from which songs are constructed. We sampled four populations in Western Australia, two of which were sampled 7 years earlier. One mainland sample area, with a large number of syllable types, is part of a geographically extensive population whereas the other three samples with smaller syllable pools are from isolated island or island-like populations. The reduction in size of syllable repertoires of the more isolated populations may have resulted from founder effect. Comparisons over the 7-year period indicated that the population proportions of the syllable types did not change significantly in either of the two resampled populations, although the correlation between sample years was stronger in the mainland population than in that of the island. In the two resampled populations, we found some new syllables, but some that were present 7 years earlier were missing. Two new syllables appear to have been derived from ones present in the earlier sample, perhaps representing cultural drift.
Article
Subdesert mesites produced ve distinct types of vocal element which they combined to produce two broad classes of song 'syllable'. One of these syllables was exclusive to males and the other was mainly given by females. Song syllables were either produced in series by single individuals to give solo songs, or 2-5 ve birds vocalised simultaneously with varying degrees of temporal precision to give duets and choruses. Pair-duets were the most common and male solos the least common form of song recorded. Females initiated and terminated signi cantly more songs than males and male syllables followed female syllables more promptly than the converse. However, the syllable structure of male and female solos changed when synchronised to form pair-duets indicating that, in contrast to most previous studies of duetting species, these songs are a function of both male and female behaviour. Only a subset of each group contributedto duets and choruses and participationwas positively correlated with mass for males and females both within and across groups. Song activity remained at a low but relatively constant rate throughout both the day and season. The wide variety of contexts in which songs were produced indicated that they serve multiple functions: some appear to be cooperative endeavours (e.g. to maintain contact in dense vegetation and 2) I am indebted to the Ministry of Water and Forest (Antananarivo) for granting me permission to conduct research in Madagascar, and to Parc Botanique et Zoologique de Tsimbazaza and Projet ZICOMA (BirdLife International) for their support of the project. I am particularly grateful to Joe Tobias, Stuart Butchart, Lucy Odling-Smee and Julien Ramanampamonjy for their ideas and invaluable help in the eld. My sincere thanks also go to Nick Davies for his advice and support, and to Michelle Hall and an anonymous referee for comments that helped improve this paper.
Article
Welcome to the R Package, an advanced multivariate and spatial analysis program for the Macintosh line of personal computers. The program and this documentation may be freely redistributed, and the latest version can always be downloaded from our WWWeb site. If you are familiar with previous versions of the R Package, we hope you will be pleasantly surprised by the improvements made in the user interface. Apart from bug fixes and new features, the algorithms that make up the R Package are virtually unchanged from version 3.0; only the way to access them and ease of use have changed. Although this manual contains some information about the foundations of multivariate and spatial analysis, all of the topics touched here are treated in much greater detail in Legendre & Legendre (1998). 1.1. The R Package highlights The R Package is a software program that offers a wide variety of tools for the exploration and analysis of multivariate and spatial data. Multivariate data is common in scientific studies, and simply means that more than one variable was studied on a sample; for instance the age, weight, sex, and species of one or many fishes is a multivariate data set. Spatial data is a subset of multivariate data, where two variables in the dataset represent some X and Y coordinates, or a latitude and longitude. If we also recorded the longitude and latitude of the capture site in the above fish data example, it could be used in many spatial analysis procedures.
Article
We examined three bioacoustical analysis methods for comparing complex sounds among different populations. We chose the D-syllable of the chick-a-dee call of the black-capped chickadee (Poecile atricapilla) because it is a broadband sound representative of a class of vocalizations, common in many animals, that resists simple subjective classification for comparative studies. We examined the properties of the D-syllable in field-recorded samples from three different populations. The first method of data extraction sampled the amplitude values of a spectrum obtained in a single fast Fourier transform (SFFT) taken at the midpoint of each D-syllable using multi-speech software. The second method employed spectrogram cross-correlation (SPCC) to obtain a matrix of similarity values between D-syllables in the samples using canary software. The third method calculated similarity values obtained from the evaluation of four acoustic features of the D-syllables derived from multi-taper spectral analysis (MTSA) using sound analysis software. Following data extraction by these three techniques, we used multivariate statistical procedures to reduce the data for examination of differences among populations and to represent in scatter-plots the patterns of clustering of the sounds. We found that the SFFT in the middle of the D-syllable provided the poorest population discrimination following statistical processing, the SPCC method produced the next clearest population separation, and the MTSA method resulted in the most distinct separation of the three populations of D-syllables. In carrying out these comparisons, we discovered that the characteristic environmental noise of a recording area can influence the signal properties of broadband sounds being compared by automated procedures, and could lead to faulty conclusions unless appropriate care is taken to mitigate the noise in which the signals of interest are embedded. Consequently we re-analyzed our data following noise reduction and found less discrete population separation overall. However, the methods of SPCC and MTSA retained the ability to separate populations, with MTSA providing the sharpest discrimination among groups.
Article
The song of the largest Malagasy lemur was extensively studied in the field between 1972 and 1984. The song’s structure is described, and the role of song in the natural history of Indriis examined by relating the naturally occurring variability of different song parameters to the behavior of habituated groups and the composition of other groups in the population. The function of an Indrigroup’s song is complex, varying according to the location and identity of animals hearing it. Territorial aspects of the song are considered in detail and the nature of primate territorial vocalizations is critically discussed.
Article
DNA fingerprinting was combined with field observations over four breeding seasons to investigate the social structure and mating system of the laughing kookaburra (Dacelo novaeguineae). Groups comprised a socially dominant pair and up to six helpers of either sex. Helpers were always recruited from young hatched in the group. Territorial inheritance, which is a feature of other cooperative breeders and an oft-cited benefit of philopatry, did not occur. Helpers only attained dominant status in an established group by dispersing into a vacant dominant position in that group. However, helpers could also form new groups by excising a new territory, often through a ”budding” process. The mating system was overwhelmingly monogamous. There were no cases of extra-group parentage in a sample of 140 nestlings; within groups of three or more birds, dominance predicted parentage almost perfectly (99.2% of 129 nestlings), irrespective of whether helpers in the group were related to one or both dominant birds. This is contrary to predictions from models of reproductive skew, possibly because they currently fail to incorporate the willingness of females to share reproduction among males.
Article
I describe siblicide in the laughing kookaburra (Dacelo novaeguineae), a reverse size-dimorphic, cooperatively breeding kingfisher. Clutches were usually of three eggs, and nestlings hatched asynchronously, with intervals of 2–72 h between successive eggs. Siblicide occurred in two temporally and mechanistically distinct episodes. The youngest nestling died in one-third of all nests within days of hatching as a result of aggression from its elders. Kookaburra nestlings attacked each other using a hook on their upper beak – a rare example of a morphological specialisation for sibling rivalry. In one-fifth of all nests, the youngest nestling starved to death much later, without overt aggression, when nestling growth rates were highest. I examined the effects of food availability and competitive disparities between nestlings on the incidence of both types of siblicide. The probability of late, starvation-mediated mortality was negatively correlated with the number of male helpers. Early, aggressively mediated siblicide occurred in nests characterised by a suite of correlated variables that I call the ”kookaburra siblicide syndrome”: (1) no male helpers attended the nest, (2) the third-hatched nestling was much smaller than the second-hatched nestling, (3) the first and second nestling to hatch were male and female, respectively, and (4) there was a short hatch interval between the first two nestlings. The kookaburra siblicide syndrome variables could be inter-correlated if they were all related to the female’s condition at the onset of incubation. Females in poorer condition may be less likely to have male helpers, more likely to lay small third eggs, and more likely to hatch the first two eggs relatively synchronously because of nutritional constraints during the onset of incubation. These females may further promote siblicide by modifying the sexes of the first two nestlings. If a female hatches soon after an older but eventually smaller brother, dominance between the first two nestlings could be destabilised. I suggest this leads to escalated aggression in the nest and the death of the third nestling, which is least able to defend itself.
Article
During a short field trip to the Special Reserve of Anjanaharibe-Sud in northeastern Madagascar, data concerning pelage coloration, behavior (especially vocalization), and ecology of indris were collected. Anjanaharibe-Sud is the northernmost locality of indri distribution. In comparison to the better-known indris from the southern part of their distribution, the indris in this region show different pelage coloration. Several types of loud vocalizations are analyzed, based on a small sample of tape recordings. Their song structure is more complicated than previously reported, containing distinct sequences of duetting. Data on behavior and ecology were collected by interviewing guides and local inhabitants. Some information contrasts with reports on the more southern indri populations. The conservation status of indris in Anjanaharibe-Sud and the future of the reserve are outlined.
Article
Vocalizations of free-ranging and captive coyotes (Canis latrans) were recorded from January 1972 through August 1975. A lexicon of 11 vocalizations was constructed based on their: (1) sounds as perceived by the observer, (2) behavioural context, and (3) physical characteristics as determined through sound spectrographic analysis. The suspected functions and relative intensities of communication of the vocalizations are described. Comparisons are made with the vocalizations of other canids.
Article
The occurrence of stable monogamy and territoriality among Old World primates in an unusual social phenomenon, and has been observed in only a few diverse primates (spectral tarsier, Tarsius spectrum; indri indri indri; Mentawai langur, Presbytis potenziani; and gibbons, Hylobates spp.). The mated pairs of all these genera have been observed to produce elaborate and complex duets. The general acoustical and organizational features of the vocal behaviour of these primates were analyzed and compared herein; in addition, the ecological and behavioural constrains affecting the evolution of their vocal behavior were also investigated. These findings strongly suggest that the occurrence of duetting in these primate species and the similarities found in the acoustical features of their vocal behavior, represents a case of functional convergence as a result of their evolution of a common social organization and similar ecological niche, and probably not mere coincidence.
Article
Territorial group size in Australian magpies (Gymnorhina tibicen) ranges from monogamous pairs to groups of more than 20 individuals. It has been hypothesized that large territorial groups result from the retention of juveniles after a breeding effort. If this is true, local populations consisting of large groups are likely to exhibit the most genetic structure, because over time similar genotypes will tend to be confined to limited areas if juveniles are predominantly philopatric. The objective of the present study was to test this hypothesis using allozyme and mitochondrial DNA data to provide indirect estimates of regional gene flow (derived from hierarchical population subdivision analyses). These data were used in combination with estimates of group size to infer patterns of dispersal among magpie populations across mainland Australia. Territorial groups were significantly larger in the south-west compared to three eastern regions. Although inferred levels of gene flow were substantial for all four regions, a striking pattern emerged from both sets of genetic data: more differentiation was evident among populations in the south-western region than in any eastern region. We conclude that levels of juvenile dispersal influence group size in G. tibicen, because in the south-western region where groups were largest, populations were most genetically differentiated. Our results suggest that contrasting population genetic structures may develop within a single species as a result of differences in social system.
Article
This study evaluates the social spacing mechanism of song as it occurs in Kloss' gibbons. The study population included individuals in 13 family groups whose composition and territories were known (TENZA 1975) plus a number of others. Sonagrams illustrate individual and sexual differences in singing. Sex differences in chorusing, countersinging and other behavior related to song are described. Variations in singing or chorusing or both are related to season, time of day, sex, age, spatial factors and social factors. The adaptive functions of singing, countersinging and chorusing are discussed. It is concluded that: (1) Song is mainly for interterritorial communication between members of the same sex, (2) male-song probably also functions in mate attraction and (3) chorusing is primarily an adaptation reducing predation risk to singing gibbons.
Article
I studied the contributions of individuals to incubation and nestling feeding in a population of cooperatively breeding laughing kookaburras, Dacelo novaeguineae. In most cooperatively breeding birds where nest success is limited by nestling starvation, related helpers increase the overall level of provisioning to the nest, thus boosting the production of nondescendent kin. However, although partial brood loss is the largest cause of lost productivity in kookaburra nests, additional helpers failed to increase overall provisioning. Instead, all group members, but especially helpers, reduced their feeding contributions as group size increased. Breeders and helpers reduced the size of prey delivered, and helpers also reduced the number of feeding visits. An important benefit of helping in kookaburras may be to allow all group members to reduce their effort. Within groups, contributions to care depended on status, sex, group size and the brood size. Breeding males delivered the most food. Breeding females provisioned less than their partner, but their effort was comparable to that of male helpers. Female helpers contributed the least food. Incubation effort followed similar patterns. The relatedness of helpers to the brood had no impact on their provisioning. Across all group sizes, helpers generally brought larger items to the nest than breeders. Copyright 2000 The Association for the Study of Animal Behaviour.
Alouatta seniculus) Behaviour 81 Singing is based on two markedly different kinds of signaling Using interactive playback to study how songs and singing contribute to communication about behavior
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Diurnal vocal patterns of the black howler monkey (Alouatta pigra) at Lamanai, Belize The comparison of harmonically rich sounds using spectrographic cross-correlation and principal coordinates analysis
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Vocal recognition of individuals and kin in free-ranging rhesus monkeys Helpers have little to laugh about: group structure and vocalization in the laughing kookaburra Dacelo novaeguineae
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The indris of Anjanaharibe-Sud, northeastern Madagascar The learning of song patterns by birds with especial reference to the song of the chaffinch Fringila coelebs
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Academic Press Matrilineal signatures in the recruitment screams of pigtail macaques, Macaca nemestrina Video analysis of siamang (Hylobates syndactylus) songs Convergence in the duetting of monogamous Old World monkeys
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Kroodsma, D. E. & Miller, E. H., eds). Academic Press, New York, pp. 237—278. Gouzoules, H. & Gouzoules, S. 1990: Matrilineal signatures in the recruitment screams of pigtail macaques, Macaca nemestrina. Behaviour 115, 327—347. Haimoff, E. H. 1981: Video analysis of siamang (Hylobates syndactylus) songs. Behaviour 76, 128—151. Haimoff, E. H. 1986: Convergence in the duetting of monogamous Old World monkeys. J. Hum. Evol. 15, 51—59.
Vocal Communication in the TimberWolf, Canis lupus L. Paul Parey Scientific The structure, context and possible functions of solo, duets and choruses in the subdesert mesite (Monias benschi)
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Schassburger, R. M. 1993: Vocal Communication in the TimberWolf, Canis lupus L. Paul Parey Scientific, Berlin. Seddon, N. 2002: The structure, context and possible functions of solo, duets and choruses in the subdesert mesite (Monias benschi). Behaviour 139, 645—676.
The Life of the Kookaburra and Other Kingfishers
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Eastman, W. 1970: The Life of the Kookaburra and Other Kingfishers. Angus and Robertson, Ltd., Sydney.
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