VOCAL BEHAVIOUR AND CALL DEVELOPMENT IN THE BULLFINCH (PYRRHULA PYRRHULA)

ABSTRACT

A sonagraphic analysis of the vocalizations of bullfinches Pyrrhula pyrrhula is presented and their behavioural contexts and functions noted. The vocal repertoire of the bullfinch is compared to that of other finches with particular attention to repertoire size and sexual specificity; the repertoire of 14–17 vocal categories is comparatively greater than that of most carduelines and the majority of vocalizations were given by both sexes. The development of nestling, fledgling and some adult calls is described. Early vocal ontogeny in the bullfinch was similar to that previously described for the chaffinch. The earliest recorded calls of nestling bullfinches showed a single fundamental. The independent use of two sound sources became apparent on the second day after hatching and the major elements of the three best studied call types were all derived from the lower fundamental of the nestling begging call.     

ACOUSTIC SIGNALLING OF THE GREAT BLACK-HEADED GULL LARUS ICHTHYAETUS PALLAS

ABSTRACT

Observations made on the behaviour and sound recordings made of the calls chiefly in the early part of the breeding season in the South Ukraine indicate that the Great Black-headed Gull Larus ichthyaetus has a limited vocal repertoire, producing only eight different types of call associated with various behavioural contexts. Sonagraphic analysis of these sounds shows that their harmonic structure is confused, like that of the calls of L. melanocephalus and L. relictus and unlike the stronger harmonic organisation of the calls of L. argentatus, L. fuscus and L. marinus. Furthermore, there is no signal warning of approaching danger. This acoustic evidence supports the theory that L. ichthyaetus is more closely related to L.relictus and other “primitive hooded” gulls than to L. argentatus and other “large white- headed” gulls of the genus.     

CLASSIFICATION OF DIVERSE CALL TYPES USING CLUSTER ANALYSIS TECHNIQUES

ABSTRACT

We investigated the problem of categorizing the repertoire of a group of highly varied vocalizations. A set of Weddell seal Leptonychotes weddellim-air calls recorded near Davis, Antarctica, were examined. The repertoire size was estimated by first subjectively assigning each call (based on auditory and spectrographic patterns) to one of a large number of provisional call types. A set of frequency, duration and waveform measurements were made on every call. For each provisional call type, the mean value of each of these measures was calculated. These mean values were used to perform Cluster Analyses of the provisional call types. Beginning with calls clustered closest together, the most similar provisional call types were successively amalgamated until further joining would link two clearly dissimilar vocalizations (rising versus falling frequency sweeps in this case). The Weddell seal repertoire contained 12 call types ranging from long sinusoidal upsweeps to growls. This procedure provides a method of estimating the minimum repertoire size of a sample of calls. Dichotomous Sorting using Principal Components Analysis can also be used to categorize calls but will probably be of greater value when applied to finding subdivisions within a single call type.     

DO THE SIBERIAN TITS PARUS CINCTUS IN SCANDINAVIA AND SIBERIA SPEAK THE SAME LANGUAGE?

ABSTRACT

The vocabulary of Siberian tits Parus cinctus in South Norway and East Siberia is compared by means of tape recordings and spectrograms. The species has many different calls that are greatly confused in the literature. In this paper ten main call types are examined. On the whole, the equivalent utterings are geographically so similar that a distinction is usually impossible or questionable. This similarity also applies to the contextual use of the calls. Consistent structural differences in certain calls were nevertheless found. The sit foraging call embraced on average a broader frequency range and was of a slightly longer duration in Siberia than in Norway. The complex ‘gargle’ system could at both places be divided into three main groups equally represented in the populations: (1) trilled, (2) tonal and (3) simple gargles. The tonal gargles are characterized by a terminal tonal element (T) that varies in shape. In Norway, tonal gargles terminating with an even or upslurred T dominated, in Siberia those with a chevron-formed T. Historically, the west-east distribution throughout Eurasia was apparently continuous until quite recently, allowing an effective gene flow. Considering the huge distance from Norway to East Siberia and the markedly resident behaviour of the Siberian tit, it is nevertheless somewhat unexpected that so few vocal differences have evolved. Several of the calls of the Siberian tit are structurally very similar to equivalent (most likely homologous) calls in other species belonging to the subgenus Poecile, e.g. the willow tit Parus montanus and the black-capped chickadee P. atricapillus, suggesting that the multicall repertoire of their common ancestor remained largely intact despite Poecile's differentiation into different species.     

BIOACOUSTIC PUBLICATIONS, 1988

ABSTRACT

We examined vocalisations of a solitary subterranean rodent, the Silvery Mole-rat Heliophobius argenteocinereus (Bathyergidae). Seven true vocalisations and one mechanical vocalisation were identified. The main frequencies of the analysed sounds (0.34–13.17 kHz) match to a great extent the frequency range suitable for transmission in underground burrows. Due to the narrow frequency range of vocalisations, motivation is predominantly expressed by the rate of tonality rather than by frequency changes. The vocal repertoire of the Silvery Mole-rat perfectly matches to Morton's MS rules, i.e. that low-frequency and harsh vocalisations indicate hostility whereas high tonal calls signalise appeasement or fear. In comparison with social species, this solitary bathyergid produces fewer calls. It lacks contact and alarm calls, but has a rich repertoire of mating calls (mating ends with duet vocalization of male and female). Acoustic signals seem to play a major role in lowering natural aggressiveness during the mating period.     

EQUIPMENT REVIEW

ABSTRACT

The Northern White Rhinoceros Ceratotherium simum cottoni is a subspecies of the White Rhino that is almost extinct in the wild. We studied the last reproducing herd kept in Zoo Dvur Kralove to describe its vocal repertoire. The calls produced by eight individuals were recorded and analysed as concerned both sound properties and behavioural contexts in which they were emitted. We distinguished 11 calls belonging to four categories: (1) tonal harmonic sounds, (2) puffing sounds, (3) growling sounds, and (4) repetitive sounds. We found an apparent similarity between acoustic parameters of homologous calls recorded in both white rhino subspecies. We further confirmed that the repertoire of white rhino calls is much larger than that reported in other rhino species. We tentatively interpret this finding as an adaptation to increased sociality. Four calls reach the infrasound range; nevertheless, they are probably not used for communication over distance. This is obvious in the case of the grouch call, which contains the highest infrasound component. There are, however, other candidates for such a communication function: the repetitive pant sound, which is not known in other rhino species. We hypothesise that the repetitions may enhance their audibility in the typical open habitats of white rhinos.     

VOCAL REPERTOIRE OF WILD BREEDING ORANGE-WINGED PARROTS AMAZONA AMAZONICA IN AMAZONIA

ABSTRACT

The vocal repertoire of Amazona amazonica during its breeding season has been recorded from wild individuals in Santa Bárbara do Pará, Pará State, Brazil. At individual nests, we continuously recorded vocalizations and behaviour for four hours in the early morning and three hours in the late afternoon, three times a week throughout the breeding season. We identified nine vocalizations that we classified in three behavioural categories: (1) Flight call—emitted when parrots arrive in the nest area; (2) Perched contact calls—two different vocalizations, one of them related to feeding, were emitted when the pair was perched in the nest area and interacted socially between themselves or with other individuals; (3) Aggressive calls—emitted when birds were in a dangerous situation, i.e. alarm (three types of calls), agonistic contact and distress calls (two types of call). The Orange-winged Parrot is a highly social species and the complexity of its social interactions is reflected in the diversity of its vocal repertoire.     

Vocalizations and morphology: interpreting the divergence among populations of Chough Pyrrhocorax pyrrhocorax and Alpine Chough P. graculus

Capsule Differences in vocalizations among populations are mostly explained on morphological bases, but historical factors may have played a significant role in differentiation processes.

Aims To investigate the relationships among vocal and morphological variation in two corvids: Chough and Alpine Chough.

Methods We used data from 11 populations of Chough and seven populations of Alpine Chough spanning the Palearctic distribution of the two species. Three data sets (morphometry, spectrotemporal parameters of trill calls and acoustic repertoire) were analysed and their variation compared with uni- and multivariate techniques.

Results In both species, morphological differences among populations were correlated to spectro-temporal variation of trills; in particular, frequencies of calls were negatively correlated to wing length (an indicator of body size). By considering only co-existing populations of the two species, the magnitude of morphological and spectrotemporal divergence was similar.

Conclusions In both species, birds from populations with similar morphology uttered similar call types and trills with close spectrotemporal features. In particular, larger-sized populations, as expressed by wing length, emitted lower pitched calls. However, the fact that dissimilarities in repertoire and morphology were correlated cannot be explained only by appealing to functional explanations, as the observed intraspecific morphological variability does not seem to be high enough to promote consistent changes in the pool of calls. In this case, historical factors might have contributed to the present pattern of differentiation.     

MATING CALLS OF THE IBERIAN MIDWIFE TOADS ALYTES OBSTETRIC ANS BOSCAI AND ALYTES CISTERNASII

ABSTRACT

The mating calls of the Iberian midwife toads, A.o. boscai and A. cisternasii show clear differences. The calls of A.o. boscai have a shorter duration (104.8ms) and a lower fundamental frequency (1.33 kHz) than those of A. cisternasii (172.0 ms and 1.45 kHz), between 12° and 16°C. In both species signal duration was found to be influenced by temperature.     

DOCUMENTATION STANDARDS FOR WILDLIFE SOUND RECORDINGS

ABSTRACT

Shearwaters are nocturnal seabirds that rely on olfaction and acoustics to communicate at night. Although previous studies have described the vocal repertoire of some shearwater species, there is a need for more precise experimental data investigating the biological relevance of these acoustic signals in this seabird group. The present paper focuses on the vocal behaviour of the Yelkouan shearwater Puffinus yelkouan, a poorly studied species which produces a single major call composed of two notes, a noisy note and a clear one. A quantitative analysis of the calls allowed to extract the acoustic parameters supporting both sexual and individual signatures. Playback experiments were conducted during the incubation period to test the ability of the Yelkouan shearwater (1) to vocally identify the sex of the emitter, and (2) to discriminate the mate from a non-mate. We showed that birds discriminate the sex of the emitter, calling back almost exclusively to calls of birds of the same sex. Among the few birds replying to calls of the opposite sex, females responded to calls of their partner only, whereas males responded equally to calls of the partner or to calls of a non-partner, suggesting that females are vocally more selective than males.     

ALARM CALLS OF THE EUROPEAN GROUND SQUIRREL SPERMOPHILUS CITELLUS AND THE TAURUS GROUND SQUIRREL S. TAURENSIS ENCODE INFORMATION ABOUT CALLER IDENTITY

ABSTRACT

Vocalizations of many mammalian species have been reported to encode information about caller identity. In this study, we analyzed 300 alarm calls from 10 free-living European Ground Squirrels Spermophilus citellus (30 per individual) and 300 alarm calls from 10 free-living Taurus Ground Squirrels S. taurensis (30 per individual), and tested the potential of these calls to encode information about the callers' identities. Discriminant analysis including all 10 European Ground Squirrel individuals correctly classified 98% of calls, and cross-validation reached a classification success of 97%. Correct classification of 98% and cross-validation of 98% was assigned when the analysis included only those individuals producing calls consisting of both elements (eight individuals). For the Taurus Ground Squirrel, correct classification was 95% and cross-validation 94% for all 10 animals. When only those individuals producing calls consisting of both elements were included (eight individuals), discriminant analysis led to 94% correct classification and cross-validation produced a classification success of 93%. These analyses demonstrate that the structure of alarm calls in these two closely related species is highly variable and that it has significant potential to encode information about caller identity.     

The communicative life of a social carnivore: acoustic repertoire of the ring-tailed coati (Nasua nasua)

The coati is a highly social mammal that features sophisticated cognitive and social abilities. We hypothesized that the ring-tailed coati, Nasua nasua, uses an extensive acoustic repertoire that correlates to their diverse range of social interactions. We tested this hypothesis by observing and recording a free-ranging managed population of N. nasua in Tietê Ecological Park (PET), in the municipality of São Paulo, State of São Paulo, Brazil. Of 404 h of sampling, 47 h of coati vocalizations were recorded over 3 years. Additional records were obtained opportunistically on other free-living populations at PET by using passive acoustic monitoring. We describe here an acoustic repertoire composed of 15 calls (12 basic calls, 2 rhythmic calls and the non-random complex calls composed of three or four different units). This diverse repertoire of signals was used in contact/cohesion regulation, foraging activities, alert or potential threat situations, playing and fighting interactions and during social isolation and acute distress. The contact call (chirp) is produced through biphonation, and other non-linear phenomena are present. Our study found a complex vocal repertoire that encourages further studies to describe the evolution of the cognitive characteristics and social abilities of ring-tailed coatis.     

BIOACOUSTIC PUBLICATIONS, 1989

ABSTRACT

Coruros Spalacopus cyanus, social fossorial rodents from Chile, use a complex acoustic repertoire with eleven different true vocalisations and one mechanical sound in various behavioural contexts. The complex of contact calls is particularly well differentiated. Juvenile coruros produced six true vocalisations of which four were structurally identical to adult calls. One vocalisation had components of two adult sounds and one occurred only in juvenile animals. Certain calls from the adult repertoire were lacking. The frequencies of sounds of juveniles were considerably higher than those of adults, with many sounds reaching the ultrasonic range. Nevertheless, pure ultrasonic sounds were not recorded.

The frequencies of the analysed sounds of coruros extended from 0.17 to 20.33 kHz with dominant frequency components between 0.17 and 10 kHz. The acoustic properties of calls are suitable for transmission above and below ground, thus providing further indirect evidence that coruros are not strictly confined to an underground way of life. Indeed, the great variability of frequency ranges, with lower frequencies always being included, reflects a specialisation for communication in variable acoustic environments.

The most distinctive and unique vocalisation of coruros is the long duration musical trilling (lasting up to two minutes), which is a long-distance call emitted in alarm and arousal contexts. Recordings of this call from natural burrows in the field in Chile showed similar structural features to vocalisations from captive colonies in the laboratory.

Our findings provide a further example of matching physical properties of vocalisations to the acoustic conditions of the habitat. However, vocalisations in subterranean rodents consist almost exclusively of short-distance calls, the trilling of coruros being the notable exception. Since the selective pressure of the acoustic environment upon the evolution of short-distance vocalisations is probably minimal, we suggest that during their evolution, subterranean mammals have matched their vocalisations primarily to their hearing range and not directly to the acoustics underground. Hearing probably has been the primary target of natural selection, serving not only for communication but also for detection of predators (and, in carnivores, of prey).     

Vocal communication of tonkean macaques in confined environments

Vocal recordings of one semi-free-ranging group and one captive group of Tonkean macaques (Macaca tonkeana) were used to establish the vocal repertoire of the species. Only the alpha male of the groups uttered a very distinctive loud call. Localization variants of coo calls were found. Alarm calls given by this species were acoustically similar to those by Japanese, rhesus, and long-tailed macaques (M. fuscata, M. mulatta, andM. fascicularis). Adult females uttered a specific variant of vocalizations during sexual morphological changes. The repertoire of agonistic vocalizations was more variable than that of any other macaque species investigated. These characteristics were discussed with reference to previous studies on vocalizations of macaque species.     

SONGS OF BLUE TITS PARUS CAERULEUS PALMENSIS FROM LA PALMA (CANARY ISLANDS)—A TEST OF HYPOTHESES

ABSTRACT

Parus major and Parus caeruleus palmensis have some song types in common. They consist of whistled element-types in different frequency ranges. Both species show territorial reactions to playback of the song-types belonging to the other species. P.c. palmensis does not share any songtypes with Central European Parus caeruleus. This is confirmed by playback experiments with the different song types, which do not elicit any territorial behaviour. The songs of P.c. palmensis also differ from those of blue tits from any other Canary Island. They may be derived from contact calls of the Lanzarote population. They have been developed by young birds that had not yet learnt their songs when they colonized La Palma from Lanzarote without reaching any of the other Canary Islands. It is suggested that the uniform song repertoire was developed by adapting the already learned contact calls to each other. The similarities to song types of P. major are due to convergence rather than character displacement. All other Canary Island tit populations share the main features of their songs, which are characterized by quick frequency changes. It seems most likely that these islands have been colonized by birds which had already learnt their songs. Differences in song repertoires are mainly caused by drift events which happen to occur because of population bottlenecks during the colonization process.     

DIFFERENCES IN THE CALLS OF EUROPEAN AND NORTH AMERICAN BLACK-BILLED MAGPIES AND THE YELLOW-BILLED MAGPIE

ABSTRACT

We compared several features of the chatter call of two races of black-billed magpies, the nominate, European race Pica pica pica and the North American race P.p. hudsonia and the yellow-billed magpie P. nuttalli. The chatter calls of the two North American species were much more similar to each other than either was to the European magpie. This information together with the recently determined similarities in the behaviour and social organisation of the two North American species, suggests that the phylogenetic affinities of these two species are closer than is implied by their taxonomic status.     

Vocal communication of wild bonnet macaques (Macaca radiata)

Field observations and spectrographic analyses of sound recordings of South Indian bonnet macaques revealed a vocal repertoire of at least 25 basic patterns. The repertoire consists of well separated sound classes and acoustic categories connected by structural intergradation. Besides structural variations within and between different elements of the repertoire, the vocal system ofMacaca radiata is characterized by regular combinations of particular basic patterns. These combinations occurred not only between calls of similar structure and function but also between calls usually emitted in entirely different social contexts. According to the qualitative analysis, sex-specific asymmetries of the vocal behaviour were less pronounced than age-dependent characteristics. The comparison of clear call vocalizations ofMacaca radiata andM. fuscata revealed significant species-specific differences on the structural and the behavioural level. Evaluations of the structural features of alarm calls of various macaque species imply marked differences between members of thefascicularis group andsinica group on one hand and thesilenus group andarctoides group on the other.     

RECENT BIOACOUSTIC PUBLICATIONS (2002 and earlier)

The vocal repertoire of the Asiatic Black Bear (Ursus thibetanus) has been poorly studied and until recently only two call types (chuffing and humming) have been described. Here I investigate the vocalizations of three wild orphaned cubs (two males and one female) reared by two observers in natural conditions in the Russian Far East. I grouped the calls into structural types, and then compared them with existing literature data on vocalizations of the same, as well as other species of the Ursidae family. In total, 1302 calls were classified visually from spectrograms into seven call types: whine, moan, yelp, grunt, snort, chuffing and humming. Classification results were verified with discriminant function analysis and randomization. I also fixed the presence of nonlinear phenomena (NLP) and articulation effects in calls. Whine was the most frequently recorded, as well as the most structurally variable call type due to a high rate of NLP. These results indicate that the vocal repertoire of the Asiatic Black Bear cubs is graded, but includes at least two discrete sound types. This work needs to be continued with further studies of vocalizations of cubs and adults of this species to verify the results of this preliminary study.     

THE SIGNIFICANCE OF MULTI-NOTE ADVERTISEMENT CALLS IN A REED FROG,HYPEROLIUS TUBERILING UIS

ABSTRACT

The reed frog Hyperolius tuberilinguis is a prolonged breeder with an advertisement call that varies in complexity from one to six click notes. Call complexity increases with chorus size, but calls containing more than three notes are rare. In playback experiments to males, subjects responded by increasing the complexity of their calls, without closely matching the stimulus and rarely exceeding the stimulus in complexity. Stimuli less complex than their own evoked a reduction in complexity. Call repetition rate remained unchanged in the responses. In two-choice phonotaxis experiments, females discriminated against one-note calls, and two- and three-note calls were the most attractive. Males thus adjust their calling in the presence of neighbours to a pattern most preferred by females. Calls of higher complexity may be more easily detected or located by females in the noisy environment of a chorus.