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Behaviour 142, 1 (Abstracts below) Bond, AB & J Diamond (2005) Geographic and ontogenetic variation in the contact calls of the kea (Nestor notabilis). Behaviour 142: 1-20. Guerra, PA & AC Mason (2005) Male competition and aggregative behaviour are mediated by acoustic cues within a temporally unstructured aggregation. Behaviour 71-90. Cirillo, J & D Todt (2005) Perception and judgement of whispered vocalisations. Behaviour 142: 113-129. Behaviour 142, 2 Collins, KT, TL Rogers, JM Terhune, PD Mcgreevy & KE Harcourt (2005) Individual variation of in-air female 'pup contact' calls in Weddell seals, Leptonychotes weddellii. Behaviour 142: 167-189. Vettin, J & D Todt (2005) Human laughter, social play, and play vocalizations of non-human primates: an evolutionary approach. Behaviour 142: 217-240. _______________________________________________ Bond, AB & J Diamond (2005) Geographic and ontogenetic variation in the contact calls of the kea (Nestor notabilis). Behaviour 142: 1-20. Regional and ontogenetic variation in the contact calls of the kea ( Nestor notabilis), an omnivorous and socially complex New Zealand parrot, were examined throughout the range of the species. We recorded samples of kee-ah contact calls from sixteen resident adults and eleven juveniles and demonstrated significant differences between age classes in the acoustic form of the vocalization. Canonical correlation analysis revealed a gradient in the form of the kee-ah call in both adults and juveniles along and across the escarpment of the Southern Alps, the primary longitudinal mountain range on the South Island of New Zealand. Although the juvenile call varies geographically along the same axes as the adult version, the aspects of the call that vary geographically are strikingly different, suggesting that the variation results from independent processes of vocal learning in the two age classes. A similar analysis of squeal vocalizations, which are only produced by juveniles, fo! und even greater levels of geographic variation. We suggest that the immediate social environment may serve as the primary factor shaping the vocal patterns of both juveniles and adults, producing localized homogeneity in call form within each age class. Guerra, PA & AC Mason (2005) Male competition and aggregative behaviour are mediated by acoustic cues within a temporally unstructured aggregation. Behaviour 71-90. We investigated the dynamics of temporally unstructured acoustic signalling aggregations, where direct interactions among males appear to be absent. The short-winged meadow katydid, Conocephalus brevipennis Scudder (Orthoptera: Tettigoniidae), is a species whose males form dense, aphasic singing aggregations. By studying both phonotactic responses and male calling behaviour towards conspecific, heterospecific, and aggregate signals (combined songs of many individuals), we examined how males might respond to acoustic signals within such aggregations, and whether such apparently unstructured groups do in fact possess spatial or temporal structure. Phonotactic bioassays demonstrate that males and females are attracted to conspecific and aggregate, but not heterospecific song. When given a choice between individual conspecific and aggregate song, females prefer conspecific song, whereas males preferred aggregate song, but only if it was presented at a lower relative intensity th! an the individual song. Response to aggregate song also depended on male sizeâthe largest males approached the broadcast speaker more closely than smaller males. Experiments examining male calling behaviour show that they respond differently to playback of conspecific song, as compared to heterospecific and aggregate signals. For heterospecific and aggregate song, males decrease their singing rate, but recover after playback ceases. Playback of conspecific song resulted in a decrease in singing that persisted after the end of playback when males were initially weak singers, but little effect for males that were initially strong singers. Males also varied the number of species-specific 'tick' elements they included in songs. Weaker singers reduced the number of ticks per song in response to playback. Stronger singers increased tick rates for conspecific and heterospecific playback, but decreased during aggregate song playback. Our results demonstrate that calling song, in ! addition to attracting females, may be used by males to facilitate agg regation and mediate the segregation of large and small signallers. Males also compete acoustically with one another by varying their overall singing rate and the frequency of tick elements relative to competing signallers. Cirillo, J & D Todt (2005) Perception and judgement of whispered vocalisations. Behaviour 142: 113-129. Whispering is regarded as a close-contact vocalisation which, in structural terms, clearly differs from normal (phonated) speech. Here, we present the first experimental evidence for specific functional differences that additionally exist between these two forms of human vocal communication. Such evidence was collected by an inquiry into the perception and also the social judgement of whispered vocalisations. Subjects were young adults (mainly students; N=202) who were exposed to auditory stimuli which, for exclusion of verbal effects, were given in artificial vocal patterns only. To test for possible social effects, our stimuli (whispered phrases or, for control, phonated phrases) simulated exposures to three socially different situations: 'monologues', 'dialogues', and 'dialogues including laughter'. Evaluation of self-report data collected after each stimulation revealed that only the whispered stimuli received significant numbers of socially negative judgements or votes,! that documented 'feelings of social segregation'. Such judgements were most frequent after exposures to 'dialogues including laughter', but less frequent after 'monologues'. Taken together our study suggests that whispering is not just a mere close-contact vocalisation, but a vocal expression with specific social side-effects. To explain these effects we presume that whispering signals primarily a strong affiliation of its users, and that such role may make other listeners feel to be excluded from a whispered interaction. Collins, KT, TL Rogers, JM Terhune, PD Mcgreevy & KE Harcourt (2005) Individual variation of in-air female 'pup contact' calls in Weddell seals, Leptonychotes weddellii. Behaviour 142: 167-189. Vocal recognition may function as a critical factor in maintaining the phocid mother-pup bond during lactation. For vocal recognition to function, the caller must produce individually distinct calls that are recognised by their intended recipient. Mother-pup vocal recognition has been studied extensively in colonial otariids and appears to be characteristic of this family. Although less numerous, empirical studies of phocid species have revealed a range of recognition abilities. This study investigated whether Weddell seal (Leptonychotes weddellii) females produce individually distinct 'pup contact' calls that function during natural pair reunions. Fifteen calls from each of nine females recorded in the Vestfold Hills, Antarctica were analysed. One temporal, nine fundamental frequency and five spectral characteristics were measured. Results of the cross-validated Discriminant Function Analysis revealed that mothers produce individually distinct calls with 56% of calls assign! ed to the correct individual. The probability of achieving this level of discrimination on novel data by chance alone is highly improbable. Analysis of eight mother-pup reunions recorded near McMurdo Sound, Antarctica further demonstrated that these 'pup contact' calls function during natural pair reunions. Behavioural analysis also revealed that pups were chiefly responsible for establishing and maintaining close contact throughout the reunion process. Our study therefore demonstrates that Weddell seal females produce calls with sufficient stereotypy to allow pups to identify them during pair reunions, providing evidence of a functioning mother-pup vocal recognition system. Vettin, J & D Todt (2005) Human laughter, social play, and play vocalizations of non-human primates: an evolutionary approach. Behaviour 142: 217-240. It has been hypothesized that the evolutionary origin of human laughter lies in the facial play signals of non-human primates. Recent studies dealing with human laughter have stressed the importance of the acoustic component of this nonverbal behaviour. In this study, we analysed the occurrence and some acoustic parameters, such as interval durations and fundamental frequency, of Barbary macaque and chimpanzee play vocalizations and human laughter during tickling. Play vocalizations occurred most often during play with close bodily contact, i.e. wrestling and tickling. In both Barbary macaques and chimpanzees, they were serially organized and had a high intra-bout variability in their acoustic parameters. These are characteristic features of human laughter which are crucial for deciding whether a given utterance will be classified as laughter in humans. Besides intra-bout variability, there was substantial intraindividual variability which was as high or higher than the inte! rindividual variability in all three species. Interval durations of Barbary macaque and chimpanzee play vocalizations and human laughter during tickling lay in a similar range. These results provide further evidence for the hypothesis that human laughter evolved from a play signal of non-human primates and raise questions about the importance of and the relationship between facial and vocal play signals in the evolution of human laughter.
