Abstracts
( Classified by  first author'  last name )

|A | B | C | D | E | F | G | H | J | K  | L | M | N | O | P | R | S | T | V | W | Z |

[Poster]
Vocal repertoire of the Black Howler Monkey Alouatta caraya in Rio Grande do Sul, Brazil

Vagner José de Albuquerque and Thaïs Leiroz Codenotti
Universidade de Passo Fundo, CP 611, 99001-970, Passo Fundo, RS, Brazil
E-mail: bdados@upf.tche.br

Primates of the genus Alouatta present extensive bioacoustic and behavioral variations, as demonstrated in the specialized literature. The Black Howler Monkey Alouatta caraya, distributed in  Argentina, Bolivia, south-western Brazil and Paraguay, uses loud sounds for communication among group members and when strangers are present in its territory. The objective of this study was to record and interpret the vocal behavior of different group members. The observational method termed "focal animal" was applied, with continuous recording of a group of 11 individuals, from June 2002 to April 2003, in a 7 ha forest fragment in Fortaleza dos Valos municipality, Rio Grande do Sul, Brazil. Vocalizations were recorded on cassettes and analyzed at the UNICAMP Bioacoustics Laboratory. Results of 261 recorded vocalizations showed that male vocalizations (n=68 recordings, 26,1%) were always associated with aggressive behavior or territorial defense. Females vocalized intensively in the presence of a potential predator (n=138, 52,9%). Cries of infants separated from their mothers were frequently recorded (n=53, 20,3%), while the cry of a female separated from the group and another female's complaint, when she was trying to remove her infant from her back, were each recorded once. Male vocalization is a low-pitched, simple grunt between 200 and 300Hz, little modulated and rhythmically repeated. In more intense emissions, a strong squeak appears in the 400 and 600Hz bands and with H2 harmonic. Females' alarm vocalizations are similar but with wider modulation and more harmonics. Cries show more complex modulation and strong H2 and H3 harmonics. These cries differ from other vocalizations specially in their higher fundamental frequency between 1,0 and 1,7 kHz. Thus, vocal communication in Alouatta caraya is generally used for defense and group cohesion, as well as territorial affirmation, by means of fairly simple homogeneous vocal structures.
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[Symposium V]
Bioacoustics and Biodiversity: Bird Point Counts

Luiz dos Anjos
Departamento de Biologia Animal e Vegetal, Universidade Estadual de Londrina, CP 6001, 86051-970 Londrina, PR, Brazil
E-mail: llanjos@sercomtel.com.br

Point counts are commonly used around the world for monitoring bird diversity. This technique of bird census depends largely on bird sound identification, especially in forest ecosystems. Thus, bioacoustics plays an important role for monitoring bird diversity. Several studies have demonstrated the  advantages of point counts over other techniques, such as those using mist nets or transects. The strong limitations to visual identification of birds in tropical forests makes sound identification an important tool. Unfortunately, our knowledge of bird sounds for species identification is quite poor in tropical forests when compared to their temperate counterparts. In Brazil, for example, only a few CDs of bird sounds are available that can aid field identification. High bird species numbers (combined with low ornithologists numbers) account for such limitations, especially in the Neotropics. These conditions do not allow a precise monitoring of bird biodiversity to be made in most of the Amazon region. Even in the Atlantic forest, where the bird sounds are better known, only a few ornithologists are able to perform point counts. There are , however, several good examples of studies in Brazilian Atlantic forests where bird diversity was evaluated or monitored. For these and other reasons, it is important to better document bird sounds as an aid to species identification during point counts and to store recordings in publicly accessible national sound archives.
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[Symposium III]
The song of the Brazilian population of Humpback Whale Megaptera novaeangliae, in the year 2000: individual song variations and possible implications

Eduardo Moraes Arraut and Jacques Vielliard
Laboratório de Bioacústica, Instituto de Biologia, Universidade Estadual de Campinas,  CP 6109, 13083-970 Campinas, SP, Brazil
E-mail for contact: jacques@unicamp.br

We studied the song of the Brazilian population of Humpback Whale Megaptera novaeangliae in its breeding and calving grounds. We made digital recordings (DAT) at the Abrolhos Bank, Bahia, Brazil, from July to November 2000, and carried out aural and spectral analyses for approximately 20 song cycles, totalizing 5 hours of song from 10 different recording events. Note type classification was based on acoustical parameters: duration, duration of the intervals between subsequent notes, and minimum and maximum frequencies. We identified 24 note types, organized in five themes. Theme order was exactly the same in all songs. The appearance of a note type and the disappearance of a phrase ending seem to be related to the progression of the season. We also detected individual variation in the emission of certain complex note types. As song alterations are transmitted culturally, this variation might be due to different composing and/or learning abilities. Listeners might use this information when deciding with which singer to interact. We thus suggest that the ability to compose and/or to learn song alterations might be indicative of singer fitness.
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[Symposium I]
Penguins and their noisy world

Thierry Aubin
NAMC-CNRS UMR 8620, Université Paris-Sud, Bât. 446, 91405 Orsay Cedex, France
E-mail: Thierry.Aubin@ibaic.u-psud.fr

Acoustic communication is essential in the socio-ecological relationships of most colonial seabird species, especially for mate-mate or parent-chick recognition. In penguins, the call an adult produces, when seeking its chick or partner among several thousands of birds, is transmitted in a context involving the noise generated by the wind, by other individuals in the colony and by the screening effect of many bodies. These factors reduce the signal-to-noise ratio and mask the signal by background noise with similar spectral and temporal characteristics. In addition, some penguin species have no nests and the absence of visual landmarks enhances the difficulty of individuals to locate the right bird on the move in a noisy crowd. Faced with this difficult problem penguins nevertheless succeed, performing acoustic identification of the partner or chick in a few minutes. How do they manage this? We have tried to answer to this question through field studies involving signal analysis, propagation and playback experiments of the identification calls of 6 penguin species. According to our results, penguins appear to adopt two strategies to optimise identification in spite of background noise: 1) behavioural strategies involve the use of meeting places, use of adapted signaling postures and searching methods; and 2) acoustical strategies involve the use of a well-matched code for identification of the signal in the noise and the use of a redundant and locatable acoustic structure. Thus, the particularly efficient acoustic system of penguins permits the recognition and localisation of individuals within a very constraining environment, a colony of thousands of birds, with intense background noise and a lack of visual cues.
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[Symposium III]
How a simple and stereotyped acoustic signal transmits individual information: the song of the White-browed Warbler Basileuterus leucoblepharus

Thierry Aubin¹, Nicolas Mathevon¹, Maria Luisa da Silva² and Jacques Vielliard³
¹ NAMC CNRS UMR 8620, Université Paris-Sud, Bât. 446, 91405 Orsay Cedex, France
² Centro de Ciências Biológicas, Universidade Federal do Pará, Campus Universitário do Guamá, 66075-110 Belém, PA, Brazil
³ Laboratório de Bioacústica, Instituto de Biologia, Universidade Estadual de Campinas,  CP 6109, 13083-970 Campinas, SP, Brazil
E-mail for contact: Thierry.Aubin@ibaic.u-psud.fr

In tropical forests, visual communication is limited by obstacles and birds communicate at long range mainly by sound. In dense vegetation, however, sounds are strongly modified during transmission over distance. To be effective, information transfer must rely upon parameters resistant to degradation. A typical and abundant bird of the Brazilian Atlantic forest, the White-browed Warbler Basileuterus leucoblepharus (Parulidae), presents a territorial song which consists of a simple signal: a succession of similar notes slowly decreasing in frequency. By playback experiments, we have shown that, for species-specific recognition, birds mainly use one feature resistant to degradation, the frequency modulation, and thus ignore the parameters sensitive to propagation. With this stereotyped feature, birds can transmit species-specific information at long range, but could individuals distinguish each other with such simple signal? Playback experiments have demonstrated that there is not only a neighbour-stranger song discrimination, but also a discrimination between songs of individual neighbours. Careful examination of the signals of different individuals revealed that one or two gaps in frequency occur, at different moments of sound production, between two successive notes. For each individual, the temporal and frequency positions of these gaps are stereotyped. By moving these gaps to earlier or later positions in the temporal domain or up and down in the frequency domain, and by playing-back these synthetic songs, recognition of neighbours was impeded. On the basis of a multivariate analysis taking into account only these gaps, it appears that listeners could distinguish at least 40 individuals. This value seems highly sufficient with regard to the spatial distribution of territories observed in the field. Thus, in spite of the simplicity of its acoustic structure, of the environmental constrains to its propagation in a tropical forest, and of the necessity to transmit species-specific information, the song of the White-browed Warbler provides an important cue for a territorial species: the neighbours' identities. [Financial support : FAPESP, FUNCAMP/FMB]
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[Symposium V]
Comparative analysis of the song of the Rufous-collared Sparrow Zonotrichia capensis (Emberizidae) between Campinas and Botucatu, São Paulo state, Brazil

Márcio F. Avelino and Jacques Vielliard
Laboratório de Bioacústica, Instituto de Biologia, Universidade Estadual de Campinas,  CP 6109, 13083-970 Campinas, SP, Brazil
E-mail: mfavelino@iar.unicamp.br; jacques@unicamp.br

The regional dialects or regiolects of the Rufous-collared Sparrow Zonotrichia capensis were researched between Campinas and Botucatu, São Paulo state, south-eastern Brazil. Thirteen localities were visited and the songs of 88 individuals recorded with a DAT (Digital Audio Tape) tape-recorder and a cardioid microphone mounted in an acoustic parabola. Comparison of the sonograms showed two areas where the songs were more homogeneous, forming two regiolects. In 11 localities most individuals shared the same song type. At the other two localities, they sang up to 5 different song types. This occurs at the boundaries of the regiolects, and was where individuals singing more than one song type were found. Similarities between song types was not related to geographic distances between the respective singers. Comparisons have also been done with recordings from other Brazilian localities, and similarities have been found with the songs of very distant birds, for instance between Conchas and Macururé in Bahia state, that are 1810 km apart.
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[Symposium II]
Differences in the whistle characteristics and repertoire of Bottlenose and Spinner Dolphins

Carmen Bazúa-Durán
Laboratorio de Acústica Aplicada y Vibraciones, CCADET, UNAM, Cd. Universitaria A.P. 70-186, 04510 México, D.F., México
E-mail: bazua@aleph.cinstrum.unam.mx

Several methods have been used to compare the whistles produced by dolphins. The two methods used in this study are: (1) a classification of whistle contours in six categories (i.e., constant frequency, upsweep, downsweep, concave, convex, and sine) and (2) the extraction of frequency and time parameters from each whistle contour. Bottlenose Dolphin Tursiops truncatus whistles are described in the same way when comparing whistle contour distributions in each of the six categories and whistle frequency and time parameters using Discriminant Function Analysis. For Spinner Dolphin Stenella longirostris whistles, each method describes whistles differently. Several facts may explain these differences in describing dolphin whistles, such as a greater fluidity of Spinner Dolphin groups when compared to Bottlenose Dolphin groups, larger geographic variation in the whistles of Bottlenose Dolphins than in those of Spinner Dolphins, an average beginning frequency 16% lower than the average ending frequency in Spinner Dolphin whistles compared to a varied relationship for Bottlenose Dolphins, and stricter criteria used to define whistle contour categories in the study of Spinner Dolphin whistles than in the Bottlenose Dolphin whistle study.
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[Symposium IV]
Implications of vocal directionality: how a songbird changes its singing behaviour depending on the context of communication

Henrik Brumm
Institute of Biology, Department of Behavioural Biology, Free University of Berlin, Haderslebener Str. 9, 12163 Berlin, Germany
E-mail: brumm@zedat.fu-berlin.de

Most animal vocalizations are not emitted omnidirectionally but are focused in the frontal direction. This directional sound radiation pattern could be advantageous in order to direct the vocalization towards the addressee, provided its position were known to the sender. On the other hand, a directional signal could be disadvantageous when the position of potential addressees is unknown (or when the audience is spread out around the sender). Thus, some animals may adjust their behaviour to either counteract or directly use the directionality of their vocalizations depending on the context of communication. We tested these hypotheses with playback experiments in six territorial male Common Nightingales Luscinia megarhynchos. While interacting with the playback of a potential rival, the examined birds showed a significant increase in the strength of singing directionality compared to pre- and post-playback observations. At the same time, subjects exhibited less lateral head movements per song during the playback procedure. These results suggest that Common Nightingales mitigate the directional sound radiation pattern of their songs and emit them in a more omnidirectional manner when the position of potential addressees is unclear. During interactions, however, when the position of an addressee is detected, songsters obviously use the directionality of their vocalizations to broadcast songs in the direction of the addressee. Our findings show that songbirds position themselves for the most effective signal transmission according to the perceived position of addressees. In addition, by facing the intended addressee the signaler may also indicate its location and thus the orientation of the vocalizing animal might serve as a signal itself.
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[Oral communication]
Comparative study of singing behavior in the Apolinari Wren Cistothorus apolinari

Paula Caycedo¹, Gary F. Stiles² and Donald Kroodsma³
¹ Instituto Alexander von Humboldt, Cra 7 Nro 35-20, Bogotá, Colombia
² Instituto de Ciencias Naturales, Universidad de Colombia, Clle 53 Cra 30, Bogotá, Colombia
³ University of Massachusetts, Department of Biology, Amherst MA 01003, USA
E-mail: pccaicedo@humboldt.org.co, pacaycedo@hotmail.com; fgstiles@ciencias.unal. edu.co; kroodsma@bio.umass.edu

Behavioral studies on singing in the genus Cistothorus have given support to two general ideas regarding the function of vocal variation among songbirds. The first idea relates song repertory size to population density, and the second relates the manner of song learning to habitat stability. Cistothorus apolinari is an endemic species of the Eastern Colombian Andes and at present is considered a critically endangered species, with two subspecies separated in altitude by almost 1000 meters. The objective of this work was to compare singing behavior of the wetland and the paramo subspecies, with regard to their repertory sizes, certain indicators of song learning, song structures and female songs, as well as to compare singing behavior in this species with congeners. This work was conducted in two different ecosystems: two wetlands of the Cundinamarca and Bogotá plateau and the wet paramo of the Sumapaz massif south of Bogotá. Song structure was determined by identifying the notes and phrases and how these combine to compose songs. For the determination of similarity among the songs of the different study locations, the coefficient of similarity of Colwell & Coddington was used. Three categories of notes were found in C. apolinari song structure. As in populations of sedentary species, song developmental in C. apolinari is by imitation. Female song is simpler than that of the males. Wetland populations shared more features of song structure among themselves than with the paramo populations. The wetland subspecies has a low population density and a low repertory size too, whereas the paramo subspecies has a high population density and exhibits the greatest repertory size of the species. Comparing this with other Cistothorus species of similar population density, this subspecies has the lowest repertory size. The social system of the paramo subspecies is different from that reported for other Cistothorus species, and this difference in social system explains differences in the social behavior of the paramo subspecies.
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[Poster]
How to identify sounds with the eyes: sonograms for bird song identification

Paula Caycedo and Luis Miguel Renjifo
Instituto Alexander von Humboldt, Cra 7 Nro 35-20, Bogotá, Colombia
E-mail: pccaicedo@humboldt.org.co; lmrenjifo@humboldt.org.co

Bird species' identities can be precisely recognized in sonograms because their acoustical patterns are very constant at the species level. This visual method facilitates the learning of songs for ornithological field researchers because it uses not only auditory but also visual memory. Bird inventories have always been used as a base for work in ecology and conservation. Using song identification and visual observations, increases the quality of these biological inventories. Nevertheless, to learn the songs of a great number of birds before beginning field work requires a long time and is often a very complex process. A species' song repertoire exhibits differences among different geographical zones, although the notes that compose a species' song repertory seems to be universal. Inventories were made at two study sites. Different types of landscape were chosen at each study site, and point counts were conducted there in order to quantify species richness by visual and auditory detection. Before field work we compiled a reference collection of species' songs and made sonograms for those birds previously reported in the study zone with the use of Syrinx software. After field work we examined sonograms of all songs recorded in the field, and species identification was made by comparing sounds and sonograms captured in the field to ones in the reference collection.
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[Symposium II]
Automated bioacoustic identification of species

David Chesmore
Intelligent Systems Engineering Group, Department of Electronics, University of York, Heslington, York, YO10 5DD, England
E-mail: edc1@ohm.york.ac.uk

Significant advances have been made in the development of methods and systems for automated identification of species that use sound for communication. Examples of current research include the detection and identification of insects, birds, bats, cetaceans and other mammals with applications ranging from simple species counting through rapid biodiversity assessment to pest species identification. The present communication will describe acoustic techniques available for species identification. The author is developing IBIS (Intelligent Bioacoustic Identification System) using time domain signal processing and artificial neural networks. Time domain signal coding (TDSC) characterises the signal in a purely temporal manner and, as such, is highly suited to real-time and hand-held applications. Two types of artificial neural network have been used for classification: multilayer perceptrons (MLPs) and self organising feature maps (SOFMs). MLPs have been tested for species recognition whilst SOFMs have been used for separating simultaneous singing insects by classifying the signal on a short time scale (e.g. 100ms). The system has been used for recognizing British and Japanese Orthoptera and Homoptera, British Chiroptera and Japanese Amphibia. Results for four species of British grasshopper give 87% to 100% recognition accuracy in the presence of interfering signals such as aircraft and birds. A hand-held generic IBIS is being built and it is hoped that a demonstration will be possible for Chiroptera. Applications for IBIS include hand-held identification aids, automated species counting, acoustic biodiversity assessment and autecological studies. In addition to recognizing species, IBIS can be trained to recognize a wide variety of sounds, both natural and man-made, leading to the potential for generic sound mapping. The presentation will discuss the development of IBIS, present results for various taxa and discuss application areas. A hand-held bat recognizer will be  demonstrated.
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[Symposium IV]
Auditory vigilance and the perception of nonverbal signal parameters: responses to whispered vocalizations

Jasmin Cirillo
Institute of Biology, Department of Behavioural Biology, Free University of Berlin, Haderslebener Str. 9, 12163 Berlin, Germany
E-mail: nimsaj@zedat.fu-berlin.de

The main body of evidence on vigilance comes from studies of visual vigilance that differs from auditory vigilance in a number of characteristics. The most essential contrast arises from the fact that the auditory system can operate without visual contact to a given target of inspection. These properties have consequences for behaviors associated with visual vigilance, such as eye or head movements, that allow an exact assessment of behavior to be made and thus facilitate its investigation. The few studies that, nevertheless, successfully investigated properties of auditory vigilance used specific methodological maneuvers, examining, for instance, the 'startle response' as a behavioral measure. In this communication, we report an experiment designed to elucidate the relationships between particular auditory stimuli, namely 'whispering voices', and the auditory vigilance of human listeners. The study was conducted with 26 adult subjects who were asked to watch a video-film and to memorize as many visual details as possible. At the same time, however, subjects were presented with a regime of auditory stimuli that reached their ears from either their left or right sides, and could thereby induce a number of specific responses, e.g., a cue-related 'head-turning'. Evaluation of relationships between stimulus properties and responses yielded results which clearly verified a sustained attention towards whispered vocalizations. Whereas response latencies were similar in all trials, response durations were significantly longer during exposure to unvoiced stimuli as compared to voiced stimuli. This effect was independent of whether subjects had problems in decoding the vocalizations or not. Further data analyses showed that whispered speech was more effective in releasing auditory vigilance than phonated speech. A reduction of room illumination raised this effect, but did not improve message recognition. In addition, our findings suggest that the observed increase in auditory vigilance was linked also to an increase in visual vigilance or, at least, a lowered threshold of visual checking responses. With this assumption as a reference, our findings invite further studies on the intrinsic processes that underlie the relationships between the two domains of vigilance in adult humans.
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[Symposium I]
Strategies that facilitate or counter eavesdropping on vocal interactions in songbirds

Torben Dabelsteen
Department of Animal Behaviour and Centre for Sound Communication (CSC), Zoological Institute, University of Copenhagen, DK-2200 Copenhagen N, Denmark
E-mail: tdabelsteen@zi.ku.dk

Most songbirds live in communication networks where eavesdropping on signaling interactions may constitute an important option for gathering relative information about other individuals' condition or quality. Field experiments have now demonstrated that songbirds of both sexes have the ability to eavesdrop on male singing interactions and utilize information about dominance relations gained from eavesdropping in later decision making. The relatively low costs and risks of eavesdropping, together with the obvious advantages of gaining such relative information about other individuals, predict eavesdropping to be a widespread phenomenon even though it is not necessarily advantageous to the eavesdropped upon. Special strategies that facilitate eavesdropping may therefore have evolved together with interactant strategies that either co-facilitate eavesdropping (public signaling), or counter eavesdropping (private signaling) or successive negative consequences of being eavesdropped (anonymity). Based mainly on the results of sound transmission experiments, this communication will review the predictions for such strategies and also give examples supporting their use by territorial songbirds. As regards the eavesdropper, predictions chiefly concern perch height and position relative to the eavesdropped. As regards those eavesdropped upon, predictions concern perch height as well as choice of communication sound and choice of the moment for interacting. [Supported by the Danish National Research Foundation]
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[Poster]
Reproductive behaviour in female Common Serins Serinus serinus is sensitive to medium-term field playback of male song during nest-building

Violaine Depraz and Paulo Mota
Laboratory of Ethology, Department of Anthropology, Faculty of Sciences & Technologies of the University of Coimbra (FCTUC), P-3000-056 Coimbra, Portugal
E-mail: violaine.depraz@libertysurf.fr

Most field playback experiments with songbirds are designed to assess male territoriality or the influence of habitat and song characteristics on sound transmission efficiency. Some of these studies address the question of female response (mate choice, eavesdropping etc.), but few studies investigate the influence of male song on female reproductive development under natural conditions. We exposed free-living female Common Serins Serinus serinus (Fringillidae) to the songs of male congeners during the nest-building (pre-laying) phase, in order to test the hypothesis that male singing activity has an effect on the female reproductive cycle. Loudspeakers linked to a CD player were placed near each nest site in the 'Playback group' and broadcast songs of one male individual for 5 hours per day in the morning (80-90 s song bouts interspersed with 60 or 70 s silent intervals). Birds were observed daily in the morning from the first day of nest discover until the first egg was laid. Our data showed that females in the playback group spent significantly more time on their nests than females in the control group that were not exposed to any playback. Moreover, since there was no difference in the mate's singing behaviour between the two groups, the greater amount of time females in the playback group spent on their nests during nest-building was a direct effect of the additional song stimulation, not a mate-mediated effect.
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[Oral communication]
Acoustic evolution in crickets: need for phylogenetic study and a reappraisal of signal effectiveness

Laure Desutter-Grandcolas and Tony Robillard
FRE2695 CNRS, Muséum National d'Histoire Naturelle, Département Systématique et Evolution, 45 rue de Buffon, 75005 Paris, France
E-mail: desutter@mnhn.fr; robillar@mnhn.fr

Most crickets emit stereotyped calling songs and show stridulums corresponding to one functional type. Exceptions concern stridulums with greatly modified tegmina and/or venation, and "unusual" calls characterized by their frequency, duration and/or intensity. This acoustic diversity remained unsuspected until recently, and current models of acoustic evolution in crickets erroneously admit that this clade is homogeneous for the features involved in acoustic communication. Few phylogenetic studies have analyzed acoustic evolution in crickets: they demonstrated that acoustic behavior could be evolutionarily particularly labile in some cricket clades. The ensuing pattern for cricket evolution may be consequently extremely complex. Two points are argued here: (1) phylogeny should always be considered when analyzing the evolution of acoustic communication in crickets, whatever characters are considered (signals, stridulatory organs or behaviors). This means that, firstly, future studies should be devoted to entire clades, and not take into account only isolated taxa; secondly, that all the characters and character states should be taken into account to allow significant reconstructions of evolutionary character transformations; and thirdly, that homologies should be carefully defined for all studied characters, even behavioral ones. (2) The factors responsible for the effectiveness of calling songs should be reconsidered and hypotheses on their potential influence on the evolution of acoustic signals tested both in reference to a phylogenetic pattern (for example, to assess correlated transformations of acoustic and ecological features), and by studies at the population level (for example, to correlate the call range and the population structure, or to test the predation risk associated with a signal structure). A better understanding of these points could help to clarify the evolution of acoustic communication in crickets.
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[Symposium II]
Qualitative and quantitative analysis of whistles produced by the Tucuxi Dolphin Sotalia fluviatilis from Sepetiba Bay in several behavioral situations

Claudia Erber and Sheila M. Simão
UFRRJ, Department of Environmental Sciences, BR 465, Km 7, 23890-000 Seropédica, RJ, Brazil
E-mail: erberbio@ig.com.br; smsimao@ufrrj.br

From July 2001 to June 2002, we recorded a total of two hours and 55 minutes of Tucuxi Dolphin Sotalia fluviatilis (Gervais 1853) sound emission from Sepetiba Bay, Rio de Janeiro state, Brazil (22°35'S;44°03'W). With a hydrophone C54 and a notebook (PCI board, sampling rate of 48 kHz), 52 min. of recordings were made during the Surface Fishing behavior, 60 min. during Deep Fishing, 31 min. during Displacement and 32 min. during Milling. A total of 3350 whistles were analyzed quantitative and qualitatively and were divided into 124 types, according to the sonogram visual aspect. The following parameters were measured using CoolEdit Pro 1.4 software: Initial Frequency (Hz), Final Frequency (Hz), Minimum Frequency (Hz), Maximum Frequency (Hz), Duration (ms), Number of Inflexions and Frequency at the Inflexion Points (Hz), Frequencies at ½, ¼, and ¾ of whistle duration (Hz), presence of Frequency Modulation and Harmonics. Ascending type whistles (N=2719) were most common, representing 82% of the total, Descending type whistles (N=240) were 7%, Low Modulation Frequency type whistles (N=348) were 10%, and other types of whistles (N=8), together with Duet type whistles (N=35), represented 1% of the total. The acoustic parameters of the most frequently registered whistles (Ascending, Descending and Low Modulation Frequency Whistles; N=3310) were: Duration 9 to 2.283 ms; Initial Frequency 1.031 to 11.066 Hz; Frequency at ¼ 2.740 to 11.110 Hz; Frequency at ½ 2.330 to 15.112 Hz. There were as many as 9 inflections in these whistles; and 142 whistles had 1 to 10 harmonics. Behaviors and average observed group size during recording influenced the whistles. We obtained an Emission Rate of 0,27 whistles/min/animal during Milling behavior; 0,29 whistles/min/animal during Displacement; 1,17 whistles/min/animal for Deep Fishing; and 1,35 whistle/min/animal for Surface Fishing. These results demonstrate the great diversity of whistles emitted by the Tucuxi Dolphin from Sepetiba Bay and they indicate a functional role of these whistles during the observed behaviors.
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[Symposium V]
Description of complex communication signals: the case of the Blue-black Grassquit Volatinia jacarina (Emberizidae) song

J. Hernán Fandiño-Mariño¹ and Jacques Vielliard²
¹ Departamento de Biologia Animal e Vegetal, Universidade Estadual de Londrina, CP 6001, 86051-970 Londrina, PR, Brazil
² Laboratório de Bioacústica, Instituto de Biologia, Universidade Estadual de Campinas, CP 6109, 13083-970 Campinas, SP, Brazil
E-mail: hernanf@uol.com.br; jacques@unicamp.br

The song of the Blue-black Grassquit Volatinia jacarina is different for every individual and the structural differences between individuals are quite complex. Samples of songs from different Brazilian localities, as well as from Venezuela and Mexico, were studied through a comparative analysis of their sonograms. From the structural point of view, the results show a song composed of a single note that is compacted in a "window" between 2 and 13 kHz and rarely occupying more than half of a second. The note is essentially pure and is repeatedly uttered with a high level of fidelity. A global frequency modulation decreases from the beginning to the end of the song, the average initial frequency being 8,1 kHz and the average final 3,5 kHz. The main song components are refered to as "Blocks" and are of three types: "Vibrations" (Buzzes or Vibratos), "Arabesques" (complex notes) and "Isolated Modulations" (simple syllables). Among other characteristics are double voices, which are highly explored by the species and probably function as codes for individual recognition. The song of the Blue-black Grassquit is considered a special case where a signature system has been developed to a high level both in the sense of increasing the inter-individual variability and decreasing the intra-individual variability and moreover by including highly refined details such as the different variations of the "Secondary Frequencies of the Vibrations" and other developments of the double voices. The song confines in a narrow "window" of time and frequencies a great number of sound elements that effectively codify individual identity and maybe even carry other messages relevant to their social life that remain to be decoded. From the geographical point of view, several kinds of similarities were found including some peculiar forms of transformations. Sharing of some elements was also a common and widely spread phenomenon along the area under study. The analysis suggests that the remarkable variability is attained through a process of progressive diversification of the songs.
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[Symposium VII]
Recording bird songs in Brazil: their value for education and conservation

J. Dalgas Frisch
Associacão de Preservacão da Vida Selvagem, Praça Uirapuru 20, CEP 05675-030 São Paulo, SP, Brazil
E-mail: dalgas@uol.com.br

By the end of the 1950s the appearance on the market of self-powered high-fidelity tape recorders made possible the large scale recording of any bird song and animal sound in the wild. I began recording in Brazil in 1959 with a Grundig recorder, but I bought my first Nagra III (still working) in 1962 and traveled all over the country with it and a large home-made aluminum parabola. Although cumbersome, it worked extremely well after some adjustments, opening an entire new field of activity. The dream of registering and recreating at will the marvelous sounds of nature became true. I selected my best recordings of the most popular and melodious Brazilian birds and launched my first LP "Aves Brasileiras" in 1963. It was an incredible instant success all over the world, and photographies appeared of the disc in the hands of Pope John XXIII, President Kennedy and the Queen of Denmark, among many other people. That was when I sensed that bird song recordings have a very strong appeal and may open great opportunities for the cause of wildlife preservation. The Associations for the Preservation of Wildlife ("Associacão de Preservacão da Vida Selvagem"-APVS) was created at that time to promote nature conservation in Brazil, through media campaigns, public awareness and government lobbying. This initiative represented a landmark in the evolution of public opinion and government policy on nature conservation issues. My conclusion, after almost half a century of dedication to the preservation of the natural richness of Brazil, is that bird song recording has been a most effective means to promote nature education and conservation.
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[Symposium VI]
Neural correlates of hormone-dependent vocal pattern of adult songbirds

Manfred Gahr
Department of Developmental and Behavioural Neurobiology, Institute of Neuro-biology, Faculty of Earth and Life Science, Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
E-mail: gahr@bio.vu.nl

Gonadal steroid hormones, the androgen testosterone and the oestrogen 17b-estradiol, profoundly influence sexual development and function of bird song and the underlying neural control circuit. The neural vocal control circuit of songbirds such as the Zebra Finch Taeniopygia guttata and the Common Canary Serinus canaria consists of anatomically discrete, interconnected areas in the avian forebrain, midbrain and hindbrain. The forebrain areas HVC (nucleus hyperstriatalis ventrale, pars caudale) and RA (nucleus robustus archistriatalis) appear to be crucial for control of the temporal organization of the song and the frequency modulation of song motor units such as syllables. Further, these vocal areas contain receptors for a number of hormones, such as the sex hormones testosterone and 17ß-estradiol or the pineal hormone melatonin, and thus might modulate the vocal pattern according to an individual's physiological condition. We present data on transient hormone-dependent modulation of the song pattern of adult male Zebra Finches and neuroanatomical and neurophysiological correlates of such modulation.
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[Symposium IV]
Long-time storage of song types in birds: evidence from interactive playbacks

Nicole Geberzahn and Henrike Hultsch
Institute of Biology, Department of Behavioural Biology, Free University of Berlin, Haderslebener Str. 9, 12163 Berlin, Germany
E-mail: nicozahn@zedat.fu-berlin.de

Assays of birdsong memorization which are based on imitation do not take into account the possibility that tutored song types may have been stored but are not retrieved from memory. Birds could use such a 'silent' reservoir of song material later in life, e.g. during vocal interactions. This possibility was examined in hand-reared Common Nightingales Luscinia megarhynchos that were exposed to songs both as fledglings and later during their first full song period in an interactive playback design. We compared the performance of imitations in the second singing season of subjects and distinguished between the following categories: (1) songs that were only experienced during the early tutoring, (2) songs that were experienced both during early tutoring and interactive playbacks, and (3) novel songs that were experienced only during simulated interactions. In their second year, birds imitated song types from each category, including those from category 1 and 2 which they had failed to imitate before. In addition, the performance of these song types was different (category 2 > category 1) and more pronounced than for category 3 songs. Our results demonstrate 'silent' song storage in Common Nightingales and point to a graded influence of time and social context of experience on subsequent vocal imitation.
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[Poster]
How to achieve interactive competence: cues from experimentally induced vocal interactions in songbirds

Nicole Geberzahn, Henrike Hultsch and Dietmar Todt
Institute of Biology, Department of Behavioural Biology, Free University of Berlin, Haderslebener Str. 9, 12163 Berlin, Germany
E-mail: nicozahn@zedat.fu-berlin.de

Vocal interactions in songbirds can be used as a model to investigate the interplay of intrinsic singing programs (e.g. influences from vocal memories) and external variables (e.g. social factors). When characterizing vocal interactions between territorial songbirds, two aspects have to be considered: (1) the timing of songs in relation to conspecific singing and (2) the use of specific song patterns that are linked in some way to a rival's songs. Responses in both domains can be used to address a territorial rival. In our study we asked whether the competence to interact depends on the opportunity to listen to interacting conspecifics during song development. We conducted interactive playback experiments on hand-reared adult Common Nightingales Luscinia megarhynchos that had been tutored in the laboratory. Only during these experiments, under controlled conditions, were the birds allowed to interact with a simulated rival. We analysed the subjects' response latencies towards broadcast playback stimuli and, in addition, the patterns they used during the playback. Our findings showed that birds were able to adjust both timing and song patterns to the playback. Therefore, prior experience with interacting conspecifics is not a precondition for engaging in vocal interactions.
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[Oral communication]
Bioacoustic investigations of the singing cicadas of the Cicadetta montana species complex (Homoptera: Cicadidae)

Matija Gogala¹ and Tomi Trilar²
¹ Slovenian Academy of Sciences and Arts, Novi trg 3, SI 1000 Ljubljana, Slovenia
² Slovenian Museum of Natural History, Presernova 20, SI 1000 Ljubljana, Slovenia
E-mail: matija.gogala@uni-lj.si; ttrilar@pms-lj.si

Most specialists of the last part of the past century agreed that the mountain cicadas in Europe and even in Asia all belong to the same species, Cicadetta montana Scopoli 1772. Small differences in the form of the wings, the colour of venation and patterns on the thorax were considered to be characteristics of local forms or subspecies. Bioacoustic investigations undertaken by our group and by the French group lead by M. Boulard during the last decade have changed this perception. On the basis of specific songs, Puissant and Boulard in 2000 described the species C. cerdaniensis. A similar case was the discovery and description of C. m. macedonica, a taxon we have discovered by its characteristic calling song. Because of its slight morphological differences, however, W. Schedl described this cicada as a subspecies. Our recent investigations in Macedonia have shown that these cicadas are absolutely sympatric with at least two other cryptic species in the C. montana species complex. Our acoustic studies as well as molecular investigations support the opinion that C. montana is a separate species. Recent bioacoustic investigations in Slovenia, Poland, Macedonia (by Gogala & Trilar) and Switzerland (by J. Sueur & J.M. Pillet) support our belief that "C. montana" is a complex of morphologically very similar species, some of which are yet undescribed, and have substantially changed our understanding of the geographic distribution of species within this group.
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[Symposium VII]
The Mexican Bird Sound Library

Fernando González-García
Instituto de Ecología, Departamento de Ecología y Comportamiento Animal, Km 2.5 Carretera Antigua a Coatepec, No. 351, Congregación El Haya, Apartado Postal 63, Xalapa, Veracruz 91000, México
E-mail: gonzalef@ecologia.edu.mx

I began recording bird songs in Mexico in 1984, when I was studying the Horned Guan´s natural history at the El Triunfo Biosphere Reserve. At that time, I was recording with a Uher 4000 tape recorder and a homemade parabola. I did not have knowledge of specialized recording techniques, nor did I know about the existence of the bioacoustics laboratories and sound libraries. So, my first recordings contained only the bird voices. Later, I began to involve myself in the world of bioacoustics, reading bioacoustics papers, visiting several web pages and taking a training course offered by the Cornell Laboratory of Ornithology. My systematic collections began in 1994. With this background I am aiming to establish the first library of Mexican birds sounds and to publicize it through the web site: www.ecologia.edu.mx/sonidos. Among its goals the library seeks to record and document the enormous diversity of Mexican birds sounds, to be used in education, entertainment, science, management and conservation programs, and to produce national and regional media publications. At the moment, our collection has around 3.000 fully documented cuts of 300 bird species, in both analogue and digital formats. We have already received requests from several researchers. To date, our web site has registered 39.000 visitors. In my aspiration to document the diversity of Mexican bird sound and those of the Mesoamerican region, and I have led several training courses in field recording techniques in several Mesoamerican countries. As a result of these courses, some countries like Costa Rica and Nicaragua and some states of Mexico have begun their own collections of bird sounds. Archiving and preserving our collection for the future and making it accessible via the internet is our most important challenge.
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[Poster]
Relationships between signal structure and function: the case of whistle-songs in the Common Nightingale Luscinia megarhynchos

Katharina Grosse and Dietmar Todt
Institute of Biology, Department of Behavioural Biology, Free University of Berlin, Haderslebener Str. 9, 12163 Berlin, Germany
E-mail: todt@zedat.fu-berlin.de

The large vocal repertoire of the Common Nightingale Luscinia megarhynchos includes song-types that, due to their structural properties, are called 'whistle-songs'. The term 'whistle' refers to the elements which compose the first half of such songs. In contrast to the majority of other song units, these elements have a relatively long duration (e.g., 0.2-0.4 s), show an almost unmodulated pitch and are repeated several times before the second half of song is initiated (Hultsch & Todt 1996). According to a hypothesis of Hultsch (1980), whistle-songs serve to attract females and also to facilitate their territorial settlement. In addition, however, whistle-songs play a role in the vocal interactions of males (Todt 1971; Naguib et al. 2001). In order to further elucidate the communicative function of whistle-songs, we conducted a comparative study on their structural details. More than 2500 samples recorded from the nocturnal singing of 22 different males were analyzed and the songs were then categorized in terms of element pitch. In addition to confirming the findings of Hultsch, our study revealed that individual males positioned a given series of whistle-elements at one of about 10 specific frequencies. The majority of whistles were between 1.5 and 4.5 kHz, but there was another set situated between 6.5 and 8.5 kHz. Territorial neighbors shared about 30% of their whistle-songs. Thus, there was a solid basis for engaging in matched counter-singing, while still maintaining the opportunity for signaling individual characteristics. With reference to the latter aspect and in line with Hultsch's hypothesis, we conclude that the use of individual whistle-songs enriches the signal spectrum of a given population of male Common Nightingales and thereby can increase the chance of successfully attracting the nocturnally migrating females.
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[Poster]
Sound production in the "Tocandira" Ant Paraponera clavata

Ana Yoshi Harada¹, Carlos José Monteiro Ribeiro¹, and Maria Luisa da Silva²
1 Museu Paraense Emílio Goeldi, Coordenação de Pesquisas em Zoologia, CP 399, 66040-170, Belém, PA, Brazil
2 Centro de Ciências Biológicas, Universidade Federal do Pará, Campus Universitário do Guamá, 66075-110 Belém, PR, Brazil
E-mail for contact: ayharada@museu-goeldi.br

The Neotropical "Tocandira" Ant Paraponera clavata (Hymenoptera: Formicidae: Ponerinae) emits different sounds when its nest is submitted to mechanical shock. We found that workers emerging from the nest repeatedly emitted sounds at frequencies of 4 to 20 kHz during two seconds after nest perturbation. When held in forceps, these workers also stridulated at interval of 0.4 seconds. We hypothesize about the communication involved (alarm) and mechanics of sound production.
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[Symposium V]
Structure and function in bird songs: deciphering songs and their information in European songbirds

Hans-Wolfgang Helb
University of Kaiserslautern, Department of Biology, Division of Ecology, P.O. Box 3049, D-67653 Kaiserslautern, Germany
E-mail: hhelb@rhrk.uni-kl.de

The richness in bird species' songs, calls and instrumental vocalizations always surprises us, especially at the beginning of the breeding season. At the same time we know that we still are neither able to understand nor able to reliably estimate the acoustic repertoire of one species or one individual to its full extent. The modification of signals and single acoustic parameters in songs and calls and their implicit function still are often unknown to us. Only permanent and patient observations in the field, as well as small experimental interventions (e.g. territorial playback experiments), help to generate specific ethological situations that can reveal the 'function of acoustic signals-puzzle' step-by-step. The Dunnock Prunella modularis, for instance, yields micro-genetical behavioural information by the choice of perch, the duration and the sound pressure level of the strophes and the length of intervals between single strophes. Which type of strophe to use in which context does play a further and important role in the acoustic communication of the Great Tit Parus major and the Yellowhammer Emberiza citrinella. The Willow Warbler Phylloscopus trochilus shows a highly detailed insight into the function of bird song by the use of elements and structure of the strophes apparently especially designed for territorial conflicts.
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[Poster]
Cognitive processes involved in the development of large song repertoires

Henrike Hultsch and Dietmar Todt
Institute of Biology, Department of Behavioural Biology, Free University of Berlin, Haderslebener Str. 9, 12163 Berlin, Germany
E-mail: hultsch@zedat.fu-berlin.de

Several properties of Oscines bird song make it a unique paradigm of biocommunication. First, singing develops by vocal imitation of individually experienced signals. Second, singing, though strictly serial in time, shows a clear hierarchical organization. Finally, several species develop a large number of different vocal patterns and their sequencing points to sophisticated rules of pattern retrieval. The large repertoire of distinct song-types that hand-raised Common Nightingales Luscinia megarhynchos develop as imitations of heard songs, allows us to study the impact of learning on different levels of behavioral organization. We describe how experience affects the performance of long sequences of songs (inter-song level) and suggest that cognitive accomplishments are involved in the development and use of song by Common Nightingales. Besides order competency, i.e. the ability to represent acquired song-types in their serial order, the birds' singing shows a regime-related clustering of imitations. That is, imitations of songs acquired in a particular tutoring regime or context are sequentially associated in the birds' singing performed several months later. Furthermore and on a still higher level of hierarchy, Common Nightingales may organize their performance according to non-acoustic cues which, during the exposure to songs, were associated with the acoustic stimuli. Such stimuli were experienced in different tutoring contexts. Thus, the birds memory finally holds song information that is categorized according to non-acoustical cues.
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[Oral communication]
Condition dependence of a multicomponent sexual signal in the Field Cricket Gryllus campestris

Alain Jacot, Hannes Scheuber and Martin W. G. Brinkhof
University of Bern, Zoological Institute, Division of Evolutionary Ecology, Wohlenstr. 50a, CH-3032 Hinterkappelen/Bern, Switzerland
E-mail: alain.jacot@esh.unibe.ch

In choosing a breeding partner, females in many animal species select among the available males on the basis of a variety of signaling traits. Theoretical models of signaling evolution predict that multicomponent ornaments convey specific information on different aspects of male quality, such as current condition and past juvenile development. By varying food availability under laboratory and field conditions, we experimentally investigated in adult male Field Crickets Gryllus campestris the effect of current and past nutritional condition on the calling song, a multicomponent sexually selected signal. We found that current nutritional condition affects calling activity  and chirp rate positively. Other song characters such as chirp duration, syllable number, loudness and carrier frequency were not affected by the food treatment. Juvenile nutritional conditions affected the structural size of adult males and, thereby, the carrier frequency of the calling song. The calling song of the Field Cricket thus contains discrete information on the current nutritional condition, as well as on the past juvenile development of the signaller.
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[Symposium VI]
Bird song and brain

Michel Kreutzer
Laboratoire d'Ethologie & Cognition comparées, Université de Paris X - Nanterre, 200 avenue de la République, Batiment H, 92 001 Nanterre cedex, France
E-mail: Michel.Kreutzer@u-paris10.fr

Many fields of research on vertebrates are concerned with the relationships between brain and acoustic communication. For many years Oscines birds have been used as models for such research. After the seminal publications of Nottebohm on the Common Canary Serinus canaria, many laboratories have been working on this subject. One of the most important processes investigated in these studies concerns the brain mechanisms involved in song production and recognition during learning and during recuperation after brain lesion. From these studies, new questions have emerged. We will firstly examine how similar and different are the processes of song production and recognition between juveniles and adults. And secondly, we will focus on research demonstrating that the intensity and the level of recuperation (song production or recognition) depend of the size and the side of the brain lesion.
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[Symposium VIII]
Acoustic communication in the Red-vented Bulbul Pycnonotus cafer

Anil Kumar
Wildlife Institute of India, Post Box 18, Chandrabani, Dehradun- 248 001, India
E-mail: anil_rathi@yahoo.com

The Red-vented Bulbul Pycnonotus cafer is a common, widely-distributed resident  songbird of India. Acoustic signals of 36 individuals were recorded periodically from a local population in Haridwar (29°55'N; 78°08'E) from April 1999 to February 2000 and in Dehradun (30°26'N; 78°06'E) from February 2002 to March 2003, using a JVC zoom MZ-500 shotgun microphone and Sony CFS 1030S tape recorder. Behavioural correlates were used to infer the possible meanings of signals. After editing, cuts of high quality recordings were analysed with the help of a sound analysis workstation and Avisoft SASLab Pro (version 4.1) software. Individuals were observed singing throughout the year. Most songs were discrete type, composed of strophes, preceded and followed by temporal gaps. In a song bout, usually same types of strophes were repeated several times in a stereotyped manner with minor structural variations of elements before the switching on another type of strophe. Sometimes a single element type was found interjected between two distinct strophes. Incomplete strophes were also identified. Duration of strophes was about 0.65 to 1.2 s (mean=0.79±0.08 s, n=124) and gap between strophes was 3 to 9 s (mean=4.88±0.06 s, n=124). The range of frequency varied from 1.25 to 8.00 kHz. Most strophes were composed of 2 to 6 elements often dissimilar in structure. Behavioural observations revealed that the biological function of song in this species appeared to maintain pair-bond and to synchronize breeding activities. In some recordings singing rate (phrases per minute) and song complexity levels (types of elements per minute) were much higher (about four times the normal singing rate). It seems that individuals used type-A songs (common throughout the year) to maintain their pair-bonds and type-B songs (rare, fast and complex) for mating. Different types of context specific calls were also identified, these were: Roosting calls, Alarm calls, Begging calls, Distress calls and Pre-flight calls.
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[Symposium I]
Degradation of song in a species using nesting holes: the Pied Flycatcher Ficedula hypoleuca

Helene M. Lampe¹, Torben Dabelsteen², Ole N. Larsen³ and Simon B. Pedersen²
¹ Dept. of Biology, Div. of Zoology, University of Oslo, P. O. Box 1050, Blindern, N-0316 Oslo, Norway
² Department of Animal Behaviour & Centre for Sound Communication, Zoological Institute, University of Copenhagen, Tagensvej 16, DK-2200 Copenhagen N, Denmark
³ Centre for Sound Communication, Institute of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
E-mail: h.m.lampe@bio.uio.no

Bird sounds are inevitably degraded during transmission through the habitat from a sender to a receiver, and for hole-nesting species sounds are predicted to be further degraded for a receiver inside the nest hole compared to a receiver outside the nest. Exactly how greatly the signal is degraded will depend on such factors as the shape of the nest cavity, type and condition of the nest hole tree or nest box, position of the bird inside the nest cavity, and the nature of the sound signals. We investigated these factors in a sound transmission experiment with the song of the Pied Flycatcher Ficedula hypoleuca (Muscicapidae). Ten different song elements were transmitted over three different distances, along three different transects in a Danish mixed-deciduous forest, to microphones placed inside and outside a nest box. On average, song degradation was much greater inside than outside the nest boxes, especially with respect to excess attenuation, that was about 10 dB higher inside nest boxes, and with respect to blurring of the song elements, that almost doubled inside the nest boxes. Being inside a nest box therefore strongly reduces a Pied Flycatcher's possibility of detecting and recognizing songs or eavesdrop on singing interactions.
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[Symposium I]
Does the environment constrain avian sound localization?

Ole Næsbye Larsen
Centre for Sound Communication, Institute of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
E-mail: onl@biology.sdu.dk

Each member of an acoustic communication network continuously monitors the acoustic activities of other network members. Potentially, it is important for animals to keep track not only of the other network members' identities and social interactions but also of their changing locations in space relative to the receiver. Localization of a sound source implies determining its direction and distance from the receiver. We will review current knowledge about peripheral and central mechanisms for avian sound localization, proposes what are the most important directional cues in sound signals, and explores the types of environmentally induced changes, such as velocity gradients and reverberating surfaces, that could heighten ambiguity in sound source location by distorting the cues. Current knowledge is still insufficient, partly because physiological mechanisms are studied in well-defined laboratory settings using few 'laboratory species' while field studies are performed in a variety of environments and with various species, mainly under favourable weather conditions. Recent laboratory studies in Budgerigars Melopsittacus undulatus, for instance, have investigated the advantages and limitations of the inherently directional pressure-difference receiver of the coupled eardrums and the properties of the echo-suppressing mechanisms in the central nervous system. On the other hand, a number of field studies have investigated bird ranging and recent ones imply surprisingly high precision in sound localization even by birds living in dense vegetation. [Supported by the Danish National Research Foundation]
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[Oral communication]
Song structure and the size of the song control system in captive Common Canaries Serinus canaria

Stefan Leitner¹ ² and Clive K. Catchpole¹
¹School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW 20 0EX, UK
² Max-Planck-Institut für Verhaltensphysiologie, D-82319 Seewiesen, Germany
E-mail: leitner@mpi-seewiesen.mpg.de

In songbirds it is still not clear which parameters determine the size of the song repertoire and the size of the song control system in the forebrain. It has been reported that male Common Canaries Serinus canaria increase song repertoire size with increasing age. Here we investigated whether age has an effect upon both the song structure and the morphology of two song control nuclei (HVC and RA) that are important in song production. We recorded songs from an aviary population of one- and two-year-old male domesticated Common Canaries. Repertoire size, number of sexually attractive (sexy) syllables and size of song nuclei, HVC and RA, did not differ between one- and two-year-old males. Neither did we find a significant correlation between syllable repertoire size and the size of HVC or RA in any of the groups. However, HVC size was positively correlated with the proportion of sexy syllables in the repertoires of two-year-old males. In both groups of males, the size of the song repertoire and the number of sexy syllables were strongly correlated, but the highest ratio of sexy syllables was found in birds with medium-sized song repertoires. It seems that older and more experienced males may enhance vocal performance by modifying the control of syllables rather than by increasing repertoire size or neural space.
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[Keynote lecture]
Innateness and the instinct to learn

Peter Marler
Animal Communication Laboratory, Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, USA
E-mail: prmarler@ucdavis.edu

Concepts of innateness were at the heart of Darwin's approach to behavior and central to the ethological theorizing of Lorenz and, at least to start with, of Tinbergen. Then Tinbergen did an about face, and for some twenty years the term "innate" became highly suspect. He attributed the change to Lehrman's famous 1953 critique in which he asserted that classifying behaviors as innate tells us nothing about how they develop. Although Lehrman made many valid points, I will argue that this exchange also led to profound misunderstandings that were ultimately damaging to progress in research on the development of behavior. The concept of  "instincts to learn," receiving renewed support from current theorizing among geneticists about phenotypic plasticity, provides a potential resolution of some of the controversies that Lehrman created. Bioacoustical studies, particularly on song learning in birds, serve both to confirm some of Lehrman's anxieties about the term "innate," but also to make a case that he threw out the genetic baby with the bathwater. The breathtaking progress in molecular and developmental genetics has prepared the way for a fuller understanding of the complexities underlying even the simplest notions of innate behavior, necessary before we can begin to comprehend the ontogeny of behavior.
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[Poster]
Subsong development in fledgling Meyer's Parrots Poicephalus meyeri: tutoring evidences

Simone Masin, Renato Massa and Luciana Bottoni
Università degli Studi Milano Bicocca, Dipartimento di Scienze dell'Ambiente e del Territorio, Piazza della Scienza, 1, 20126 Milano, Italy
E-mail: luciana.bottoni@unimib.it, renato.massa@unimib.it, bioacust.lab@unimib.it

Subsongs are 'vocal trials' uttered by young birds that practice and improve their performing of songs and duets. Among songbirds subsongs are frequently displayed in long, low-volume sessions by fledgling and immature individuals during the first year of life. Recent studies in Zebra Finches Poephila guttata point out the main rôle of adult males as tutors in enhancing song learning in young birds: isolated individuals showed problems in learning songs in comparison with siblings allowed to hear and learn from an interactive tutor. However, evidence about parrot subsong development remains mostly anecdotal or limited to learning in Budgerigars Melopsittacus undulatus. The aim of our research is the study of subsong onset and repertoire development in six captive-born, parent-raised Meyer's Parrots Poicephalus meyeri, from fledging until complete independence. Chicks were born in two successive years, 2000 and 2001, from the same pair of captive parents, and their subsongs were recorded with a Tascam DAT recorder equipped with a directional microphone. Data were digitalized and analysed with Canary 1.2.4 software: syllables, minimal discrete units in subsongs, were isolated and classified for each chick from fledging until complete independence. Spectrographic measurements allowed us to compare the fledgling's subsong syllables with the father's repertoire, both for frequency and time parameters (Pkf0, Fmin, Fmax, ?f, total length, pause length). Statistical analysis showed a definite, increasing pattern in similarity between chick and father vocalizations, ranging from 0% in the first week after nest emergence to 100% at time of complete independence. This evidence supports the "father as main tutor" hypothesis, since several breeding pairs of African Parrots Psittacus erithacus were caged nearby in the parrot breeding centre and fledglings were exposed to a wide range of acoustical stimuli. Nevertheless, the father's vocal units were mainly used in assembling chicks' repertoire.
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[Symposium I]
Are communication activities shaped by environmental constraints in reverberating and sound-absorbing forest habitats?

Nicolas Mathevon¹, Thierry Aubin¹, Torben Dabelsteen² and Jacques Vielliard³
¹ NAMC CNRS UMR 8620, Université Paris-Sud, Bât. 446, 91405 Orsay Cedex, France
² Department of Animal Behaviour & Centre for Sound Communication, Zoological Institute, University of Copenhagen, Tagensvej 16, DK-2200 Copenhagen N, Denmark
³ Laboratório de Bioacústica, Instituto de Biologia, Universidade Estadual de Campinas,  CP 6109, 13083-970 Campinas, SP, Brazil
E-mail for contact: mathevon@univ-st-etienne.fr

In songbirds, communication networks often consist of several individuals and may persist for a relatively long time in certain habitats. Information transfer among individuals in the network plays an important role in both territorial conflicts and mate choice. In the dense vegetation of temperate or tropical forests, these communication processes may be impaired by propagation-induced modifications of transmitted sounds. We will focus on adaptations that allow individuals to manipulate the range of their signals, as well as the efficiency of signal reception in a sound-degrading environment. Choice of song perch, for instance, is an important option for controlling sound communication since it may allow circumvention while taking advantage of heterogeneities and patterns in the surrounding vegetation. The choice of the time of day for communication is also important. For instance, dawn does not necessarily constitute a good time for communicating over long distances. On certain days attenuation may be highest at dawn, and the high background noise from simultaneously vocalizing birds considerably masks sound reception. However, this impairment to sound communication at dawn may also be utilized for privatised communication. Finally, the coding of information can be adapted to the propagation constraints. The song of the Brazilian White-browed Warbler Basileuterus leucoblepharus is a good example of this: besides providing species information, this song allows the receiving bird to individually identify the singer, to determine its distance, and perhaps even to estimate its motivation. Each type of information is encoded into particular acoustic parameters that differ in their "active spaces." Species identity is encoded into a parameter that resists sound degradation, whereas individual identity and motivation are encoded into parameters more sensitive to propagation-induced modifications. Cues for distance determination are provided by the propagation-induced modifications.
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[Symposium III]
A memory like a Fur Seal female: long-lasting recognition of pup's voice by mothers

Nicolas Mathevon¹, Isabelle Charrier² and Thierry Aubin¹
¹ NAMC-CNRS UMR 8620, Université Paris-Sud, Bât. 446, 91405 Orsay Cedex, France
² Department of Psychology, University of Alberta, Canada
E-mail for contact: mathevon@univ-st-etienne.fr

In otariids, mothers and pups develop the capacity to mutually recognize their voices. Pups are able to identify their mother's voice a few days after birth. For females, this discrimination seems to occur during the first few hours after parturition. However, during the breeding period, mothers are confronted to a major problem: the change in the acoustical characteristics of their pup's calls. We investigated this problem in the Subantarctic Fur Seal Arctocephalus tropicalis. In this species, adults come ashore to breed in dense colonies and lactating females have to alternate foraging trips at sea with periods ashore when they suckle their pups. We first performed an acoustic analysis of pups' calls from birth to weaning to identity the successive different versions of these calls. Second, we did playback experiments just before weaning to test if females retain the different versions of their pup over a long time period. The acoustic analysis of pup's calls reveals that several characteristics of pup's vocalizations change with age. Playback experiments demonstrate that females still recognize all the successive immature and mature versions of their pup's calls. To our mind, this long-term memorization seems to be a by-product of the strong permanent pup's voice learning from birth to weaning since no apparent adaptive benefit seem to arise from this capacity.
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[Symposium VI]
Mapping vocal communication pathways in birds with inducible gene expression

Claudio V. Mello
Neurological Sciences Institute, Oregon Health and Science University, 505 NW 185th Avenue, Beaverton, OR 97006, USA
E-mail: melloc@ohsu.edu

Mapping the expression of activity-dependent genes in the brain has been very useful to reveal activation patterns associated with specific stimuli or behavioral contexts. In addition, the programs of gene expression induced by activity are likely associated with neuronal plasticity and may be involved in long-term memory formation. Analysis of the immediate-early gene zenk (a.k.a. zif-268, NGFI-A, egr-1 or Krox-24) has been used to generate high-resolution maps of brain activation associated with perceptual and motor aspects of vocal communication in songbirds and other avian groups. This approach has generated novel insights into the organization of brain pathways for vocal communication in birds. Some of the highlights include: 1) the identification of the caudomedial neostriatum (NCM) as an area involved in song auditory processing and possibly the formation of song-related auditory memories; such memories may then affect individual recognition, mate selection and vocal learning; 2) the discovery of a possible basis for a syllabic auditory representation in NCM; 3) the finding that the anterior forebrain pathway within the song control system is actively engaged in song production during adulthood; 4) the finding that the context of singing affects brain activation patterns associated with singing behavior; 5) the identification of auditory and vocal control brain areas in parrots and hummingbirds, the only vocal learning birds besides songbirds. The latter comparative approach revealed striking similarities in auditory and vocal control pathways, indicating that these pathways evolved under strong evolutionary constraints in vocal learning avian orders.
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[Symposium IV]
Functional analysis of Neotropical primates vocalizations: the problem of combinatory contact calls

 Francisco D. C. Mendes¹ and César Ades²
¹ Depto de Psicologia e Instituto de Trópico Subúmido, Universidade Católica de Goiás, Av. Universitária 1440, CP 82, 74605-010 Goiânia, GO, Brazil
² Departamento de Psicologia Experimental, USP, Av. Prof. Mello Moraes 1721, 05508-010 São Paulo, SP, Brazil
E-mail: francisco@ucg.br; cades@usp.br

Functions of animal vocalizations are usually interpreted through the matching of vocal patterns with associated contexts of emission, and the vocal and non-vocal responses of potential listeners. For stereotyped signals and for those that represent gradients across few acoustic variables, functional interpretations may depend solely on data about few contextual parameters. Primates, however, frequently exchange vocalizations with other group members in a variety of contexts, without apparent non-vocal responses from potential listeners. Some of these so-called "contact calls" present considerable acoustic variability and may be formed by combinations of a limited set of acoustic units. Sequential exchange calls of Northern Muriquis Brachyteles hypoxanthus, for instance, are formed by an average of 10 acoustic elements (notes), combined from a set of 14 categories of elements. Generative rules of phonation and Markovian processes in the sequences of elements were identified in a sample of 648 calls of adult members of the Matão group of Northern Muriquis at the Caratinga Biological Station. Some of the patterns of combination were associated with contextual parameters (i.e. reproductive status of callers, presence of other group members, degree of dispersion among callers). On the other hand, 534 different sequences of elements were found in the 648 calls analyzed. We utilize these results, as well as published results on vocalizations of capuchin monkeys (Cebus spp.) and callithrichids (e.g. Saguinus oedipus. and Cebuella pygmae) to argue that, for combinatory intra-group exchange calls at least, three common procedures should be avoided: a) the attribution of the generic label "contact call"; b) assumption that information content is transmitted at the call level alone and that each broad vocal pattern has one specific function; and c) the assumption that information transfer in combinatory vocalizations may only be accomplished by mechanisms similar to human language. We recommend Robinson´s approach to these vocalizations as systems of intra-group spacing as more appropriate to formulations of scientific problems and hypotheses, and indicate some possible future research on the theme.
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[Symposium IV]
Bioacoustics of human whistled languages: an alternative approach of the cognitive processes of language

Julien Meyer
Laboratoire de Dynamique du Langage (DDL)-CNRS, Institut des Sciences de l'Homme (ISH), 14 Avenue Berthelot, 69363 Lyon Cedex 07, France
E-mail: Julien.Meyer@etu.univ-lyon2.fr

Apart from articulated, vocal language that is our classical mode of communication, some populations in many parts of the world use a very different, complementary system of acoustic communication called whistled language because it is based on the modulation of whistles. Nowadays, ten whistled languages have been partially described and studied linguistically or bioacoustically. In addition, as many as sixty other languages are suspected to still have a whistled equivalent and have never been studied. Their existence seems to be mainly associated with special conditions of human communication, particularly (a) long-distance speaking between people living in places where rugged topography separates them in terms of travel times, even when they may be in visual contact (which results in a certain isolation of individuals); or (b) local secrecy in speaking about or with the environment (for hunting or fishing) or about others (in love, religious, political or social messages). When these languages are not threatened with extinction, their linguistic range is not physically limited, but only culturally. The whistles are represented by modulations of frequency, centered around 2000 Hz (+/-1000 Hz) and that sometimes reach 130 dB at one meter from the mouth of the whistler. Their range can reach up to 10 km (as it has been verified in La Gomera, Canary Island), and the messages remain understandable, even if at this distance the signal is much deteriorated. Whistled speech is often tightly associated with some talking musical instruments (such as flutes, guitars, harps, gongs, drums and khens) and the whistle as a means of conveying information has some equivalents in the animal kingdom (for example, in some birds, cetaceans and primates) providing opportunities to compare the acoustic regularities of the respective signals and to analyse them with the same dedicated software. The aim of this communication is to underline that studies on these whistled equivalents of languages have already shed a new light on the faculty of language, even if this phenomenon is often only superficially known and is disappearing slowly. It is a living phenomena that may provide key information about the role of rhythm and melody in language. It requires a multidisciplinary approach where bioacoustics have great a role to play.
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[Poster]
Properties of pressure difference receiving ears

Axel Michelsen and Ole Næsbye Larsen
Centre for Sound Communication, Institute of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
E-mail: onl@biology.sdu.dk

In many small animals, the eardrums receive sound at both their outer and inner surfaces. Eardrum vibrations vary greatly with the direction of sound incidence, although the pressure amplitude at the ears hardly varies. The sound reaching the inner surface often arrives from the other ear and is propagated through an air-filled channel connecting the middle ears. In such pressure-difference receivers, a change in the direction of sound incidence affects the relative phase of sound at the eardrums, which is converted to a difference in the vibration amplitude of the eardrums. In recent years, this concept has become the standard explanation for directionality in small animals, almost a magic formula, but little has been done to investigate the problems and limitations of such systems. We have used a mathematical model to study the physics of pressure-difference receiving ears, and have found that the directivity obtained in such systems is critically dependent on the properties of the transmission pathway that guides sound to the inner surface of the eardrum. Useful directivity pattern for animals that live in habitats with much sound degradation should combine a high sensitivity in the forward direction with good discrimination between ipsi- and contra-lateral sounds. Such patterns are only possible when the amplitude and phase of the sound reaching the inner ear matches the variation in relative phase of the sounds acting on the outer surfaces of the eardrums. It is therefore not a trivial matter for the animals to obtain good directional hearing within a broad frequency range. [Supported by the Danish National Research Foundation]
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[Poster]
Motivational and ontogenetical variability in Guinea Pig Cavia porcellus pup distress whistles

Patrícia Ferreira Monticelli, César Ades, Rosana Suemi Tokumaru and Ludmila Constantinov
Departamento de Psicologia Experimental, USP, Av. Prof. Mello Moraes, 1721, 05508-010 São Paulo, SP, Brazil
E-mail for contact: monticel@usp.br

Isolated Guinea Pig Cavia porcellus pups emit high-pitched distress whistles composed of repeated harmonic notes with marked frequency modulation and stable individual differences. In order to assess the influence of short-term (motivational) and long-term (ontogenetical) variables on whistle structure, we recorded the distress whistles of 6 pups during 15-min isolation sessions and compared (1) the first to the last 30 whistles notes of a session (on the 8th day of life), assuming that distress would change throughout the session; and (2) 30 notes recorded on the 8th day of life to 30 notes recorded on the 14th day of life. Acoustic (Avisoft 3.0) and statistical (Mann-Whitney, SPSS 10) analysis revealed that: (1) from the beginning to the end of sessions, all pups whistle notes became shorter and, in most animals, higher in pitch (increase in initial, mean and dominant frequencies) and with fewer harmonics; all pups showed increased internote intervals; and (2) with aging (from the 8th to the 14th day of life) pups' whistles became longer, the number of harmonics decreased, and the interval between notes increased, while older pups remained silent for longer periods. Results show that whistle features can vary according to motivational state (stress being higher at the end than at the beginning of an isolation session, as observed in hormonal analysis) and that they are subject to developmental change. Guinea Pig pups' responsiveness to isolation decreases progressively until whistling disappears at weaning age. [FAPESP, grant 01/03188-3]
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[Symposium VIII]
A commonly overlooked issue in the application of discriminant function analysis to acoustical data

Roger Mundry and Christina Sommer
Institute of Biology, Department of Behavioural Biology, Free University of Berlin, Haderslebener Str. 9, 12163 Berlin, Germany
E-mail: rmundry@zedat.fu-berlin.de

A commonly used statistical method in the analysis of multivariate acoustical data is Discriminant Function Analysis (DFA). However, the procedure is quite commonly used incorrectly. In particular, it is also applied to factorial data sets which include more than one independent variable although the DFA does not allow for the analysis of such data. For instance, DFAs were used to test for differences between sexes or social groups using data sets that included several calls per subject and thus, in fact, represented a nested structure (with individual nested within sex or group). Other examples of incorrectly implemented DFAs include for instance analyses of differences between contexts on crossed data sets which included calls from the same subjects recorded in different contexts. In this paper we demonstrate that a DFA on such factorial data may lead to grossly incorrect results and that it usually tends to (sometimes drastically) overestimate the discriminability between groups, sexes or contexts, for example. Furthermore, we will outline the circumstances under which such incorrect results might occur. Researchers usually have good reasons to include more than one call per subject into such an analysis (for example when only a few subjects are available or when there is large variation of call properties within subjects) and hence we developed an approach that permits the analysis of such data sets. This approach combines the advantages of the DFA with the flexibility of permutation tests. Besides briefly explaining its rationale, we will also demonstrate examples of its application.
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[Oral communication]
Seasonal variation in the behavioural responses of Budgerigars Melopsittacus undulatus to an alarm call

Gérard Nicolas, Cloé Fraigneau and Thierry Aubin
NAMC CNRS UMR 8620, Université Paris-Sud, Bât. 446,  91405 Orsay Cedex, France
E-mail: gerard.nicolas@ibaic.u-psud.fr

The understanding of acoustic communication requires study of both call production by signalers and call perception by receivers. Our study was of the analysis of the meaning given to a conspecific signal by a receiver under different contexts, in order to determine if the season could modulate the significance attached to a conspecific alarm call in a gregarious bird, the Budgerigar Melopsittacus undulatus. To investigate this relationship, birds were submitted to playback of their alarm call. The test sessions were videotaped and then analyzed frame by frame. Several qualitative responses were quantified. In winter and spring, the Budgerigars reacted differently to the information encoded in the same signal, as indicated by their subsequent behaviour. The receiver, according to the season, exhibited "alternative responses" when the same alarm call was played-back. In winter, the Budgerigars were significantly more predisposed to emit an acoustic response, while in spring they exhibited an increased motricity leading to an escape flight. Hence, according to its function, the alarm call was more efficient in spring than in winter since it elicited the adaptive response, which is escape.
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[Symposium II]
Application of automated bioacoustic identification in environmental education and assessment

Teruyo Oba
Natural History Museum and Institute, Chiba , 955-2 Aoba-cho, Chuo-ku, Chiba 260-8682, Japan
E-mail: oba@chiba-muse.or.jp

Development in electronics and computer science has lead to the introduction of a new bioacoustic tool to resolve commonly encountered problems in the identification of species in the field, for environmental education and assessment purposes. This technology not only aids our careful and skilled observation by ear but improves the quality of biological surveys and environmental monitoring. In the present communication, the future roles and possibilities of bioacoustics are discussed, providing some examples from the realm of environmental education and monitoring that focus on the use of natural sounds. Furthermore, our basic knowledge in bioacoustics and ecology is reviewed in the light of the development of new technology and the need for the establishment of bioacoustic reference collections to serve as vouchers for bioacoustic research.
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[Symposium II]
Identification of Tibicen cicada species by a principal components analysis of their songs

Eiji Ohya
Biodiversity Research Group, Tohoku Research Center, Forestry and Forest Products Research Institute, Shimo-kuriyagawa aza Nabeyashiki 92-95, Morioka 020-0123, Japan
E-mail: ejoy@ffpri.affrc.go.jp

The songs of Tibicen cicadas were used to survey possible effects (e.g. local extinction or geographical variation) caused by habitat fragmentation of patched beech forests in the Kitakami highlands, Iwate, Japan. There are three Tibicen species in the north of the main island: T. japonicus inhabits lower forests (about 500-1000 m) mainly of Red Pine Pinus densiflora or Sugi Cedar Cryptomeria japonica; T. flammatus is localized only in some higher forests (about 1000 m) composed of a variety of deciduous trees such as Beech Fagus crenata, Birch Betula tauschii and Oak Quercus mongolina; and T. bihamatus lives in much higher forests (about 1000-1500 m) mainly of Beech. Since they usually sing on the higher parts of tree trunks, their capture is difficult and, thus, their specific identification by means of their sounds is useful. Since all these three Tibicen species produce similar buzzing sounds, however, it is difficult to discriminate among them by ear. Therefore, a principal components analysis of the sound was used to aid identification. From 25 July to 29 August 2001, 20 sound samples were obtained from different parts of the Kitakami highlands. The sounds were recorded by a mini-disk recorder (Sony MZ-R90) with an electret condenser microphone (Sony ECM-MS907) and then processed by a PC with the Avisoft SASLab Pro software package. Principal components analysis was carried out using average frequency and pulse rate as the variables. High quality recordings of each species (Matsuura, 1986) were used as the controls. The cluster analysis of the principal components scores clearly discriminated T. bihamatus, T. japonicus and T. flammatus from each other.
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[Symposium III]
Loud calling in two species of howler monkeys

Dilmar A. G. Oliveira¹ and César Ades²
¹ Universidade Regional de Blumenau, Centro de Ciências Exatas e Naturais, CP 1507, 89010-971 Blumenau, SC, Brazil
² Departamento de Psicologia Experimental, USP, Av. Prof. Mello Moraes 1721, 05508-010 São Paulo, SP, Brazil
E-mail: dilmar@usp.br

Most studies on howler monkey loud calling focused on just one call type, the roar, and on only two species, Alouatta palliata and A. seniculus. Some structural variability and functional divergence occur among different species. We studied two less well-known howler species: Alouatta guariba clamitans and Alouatta belzebul belzebul. Records obtained from wild and captive animals were analyzed with the aid of Avisoft  SASLab Pro software. Roars, brief roars and barks, emitted by adult males, were found in the repertoire of both species, and these calls were usually uttered in sequences several minutes long. Female roars and mixed sequences, composed from both barks and roars, were also found for A. g. clamitans. The roar was the most divergent call between the two species: the dominant frequency in A. g. clamitans is lower than in A. b. belzebul, and two spectral amplitude peaks are usually found in the former, while a single, highly modulated peak is typical for the latter. A similar trend was found for barks, and the barks of A. g. clamitans were more variable in amplitude and duration. The modulation cycle of the roar in A. b. belzebul was shorter than in A. g. clamitans, both in the inhalant and exhalant phases. The precise evolutionary significance of such divergences is still speculative. [Financial support: CNPq, FAPESP]
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[Symposium IV]
Long-distance calls in Neotropical primates

Dilmar A. G. Oliveira¹ and César Ades²
¹ Universidade Regional de Blumenau, Centro de Ciências Exatas e Naturais, CP 1507, 89010-971 Blumenau, SC, Brazil
² Departamento de Psicologia Experimental, USP, Av. Prof. Mello Moraes 1721, 05508-010 São Paulo, SP, Brazil
E-mail: dilmar@usp.br

Long-distance calls, also known as loud calls or long calls, are widespread among primates, and several studies concentrate on such calls in just one or a few species. Few studies, however, have treated more general trends among primate long-distance calls. These vocalizations are usually characterized by great amplitude and low frequencies, features related to the long-distance propagation of sounds. Several functions have been proposed for primate long-distance calls, both in extra-group and intra-group communication. Extra-group functions could relate to sexual selection, since these calls are more typically emitted by males, with mate defense or mate attraction as likely roles. However, no general trend related to these functions has been found, with the resource defense hypothesis being more corroborated by data. Intra-group functions involve group coordination over long distances or alarm. Female long-distance calls are more studied in monogamous species, that usually perform coordinated duets. Among Neotropical primates, several species perform intra-group long-distance calls that seem more related to intra-group coordination. The more remarkable examples of extra-group directed long-distance calls are the duets of Callicebus (titi monkeys) and the roars and barks of Alouatta (howler monkeys). Our studies on howler monkeys indicate that considerable complexity and gradation exist in their long-distance calls repertoire, and that these calls also can have some role in intra-group communication. We have also found that female long-distance calls can be very important in Alouatta, implying that differences between monogamous and non-monogamous species in female participation could be less marked than usually thought. [Financial support: FAPESP, CNPq]</