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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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]
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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]
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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]
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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]
[top]
[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]
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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.
[top]
[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]
[top]
[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]
[top]
[Poster]
Acoustic male-to-male signaling
in the Cracker Butterfly Hamadryas feronia
William L. Overal
Museu Paraense Emílio
Goeldi, Coordenação de Zoologia, CP 399, 66017-970 Belém,
PA, Brazil
E-mail: overal@museu-goeldi.br
Cracker butterflies of the Neotropical
genus Hamadryas (Lepidoptera: Nymphalidae) are known for the clicking
sound produced by both sexes, reminiscent of a person cracking his knuckles.
H.
feronia (Linnaeus, 1758) is know popularly in Brazil as the "Borboleta-estaladeira"
for this reason, but to date no satisfactory explanation has been offered
for the communicative function of the sounds that are probably produced
by the wings. Observations of twelve marked males and ten females, made
in 1999 in a clearing near the Caxiuanã Bay in Pará state,
northern Brazil, showed that males competed in the presence of females
in displacing one another from perches on tree trunks and in producing
louder and perhaps longer (0.5 to 0.8 s) series of clicks in flight. This
behavior takes place especially in the afternoon and is interpreted tentatively
as lekking since perches are close together and not continually defended,
as would be expected in territorial behavior. Moreover, a tree trunk holds
no resources that these frugivorous butterflies utilize and may harbor
several males at night. Playback experiments are planned as a test of this
hypothesis. At this time, it is yet premature to generalize about the intra-specific
functions of sound production in butterflies.
[top]
[Symposium I]
A method for predicting the
acoustic degradation of birdsongs propagated through forested environments
Mark Padgham
Department of Zoology, The
University of Melbourne, Victoria, 3010, Australia
Conventional broadcast and re-recording
experiments are useful in examining the degrading effects of sound propagation
through natural environments. However, the interpretation of results generally
pertains only to the particular signals and habitats studied. The prediction
of acoustic degradation, based upon measurements of the general acoustic
properties of a habitat, would enable studies of the degradation of any
or all acoustic signals within a habitat. Such a predictive method is presented,
using parameters quantifying frequency attenuation and rates of reverberation.
Predictions are compared with the results of in situ broadcast and re-recording
experiments conducted in two distinct forests of south-eastern Australia,
each using the songs of two bird species, one endemic to each of the forests.
Very strong agreement is found between measured and predicted values for
the less structurally-complex of the forests, with agreement in the other
forest being weaker, yet still generally significant. Results are compared
both between species and between forests, providing strong evidence for
the adaptation of acoustic signals to their original habitats, as well
as confirming a method by which the study of acoustic adaptation may be
greatly enhanced.
[top]
[Symposium VIII]
Bits and q-bits as versatility
measures
José R. C. Piqueira
Escola Politécnica,
Universidade de São Paulo, Av. Prof. Luciano Gualberto, tr. 3-158,
05508-900 São Paulo, SP, Brazil
E-mail: piqueira@lac.usp.br
Algorithms were developed
to transform bird song data into informational entropy measures that capture
aspects of the variability in the song. The approach was classical and
the concept of bit was used. Now, the idea is to use quantum information
theory and the quantum bit (q-bit) concept, that will provide a more complete
versatility measure.
[top]
[Symposium VI]
Processing of vocalizations
in the inferior colliculus of the Moustached Bat Pteronotus parnellii
Christine Portfors
School of Biological Sciences,
Washington State University, 14204 NE Salmon Creek Ave., Vancouver, WA
98686, USA
E-mail: Portfors@vancouver.wsu.edu
Many animals emit spectrally
and temporally complex vocalizations during social behaviors to convey
information to conspecifics. While we understand the behavioral relevance
of some of these sounds, it is unclear how the auditory system processes
these social vocalizations. In auditory cortex some neurons show selectivity
to social vocalizations in that certain neurons respond preferentially
to one or a few social vocalizations and do not respond to other vocalizations.
Further, the neuron response to complex social vocalizations can not be
well predicted from the neuron response to pure tones. This neural selectivity
has traditionally been thought to emerge at the level of the primary auditory
cortex. However, we have recently shown that some neurons in the auditory
midbrain of the Moustached Bat Pteronotus parnellii are selective
to social vocalizations. In its inferior colliculus (IC), responses to
social vocalizations are not well predicted by responses to pure tones
but are better predicted by responses to combinations of tones. One hypothesis
is that "combination sensitivity" is a mechanism for creating selective
responses. Neurons that show combination sensitivity respond in a facilitatory
or inhibitory manner to the combination of two different frequency sounds
and do indeed show high selectivity to particular social vocalizations.
Combination-sensitive responses are common in the IC of the Moustached
Bat and have been well described in terms of their importance in encoding
echolocation signals. The finding that combination sensitivity is also
important for encoding social vocalizations suggests that this is a common
neural mechanism for processing spectrally and temporally complex sounds.
[top]
[Symposium VII]
Natural Sound Archives: past,
present and future
Richard Ranft
The British Library Sound
Archive, 96 Euston Road, London NWI 2DB, UK
E-mail: richard.ranft@bl.uk
Collections of animal sound
recordings serve many uses in education, entertainment, science and nature
conservation. Recordings of wild animals were first made in the Palaearctic
in 1900, in the Nearctic in 1929, in Asia in 1937, Antarctica in 1934,
and in the Neotropics in the 1940s; but systematic collecting did not begin
until the 1950s. Now the largest collections between them hold around 0.5
million recordings with their associated data (Alström & Ranft,
2003). They preserve the sounds of all kinds or animals with multiple examples
of their seasonal, geographical and individual variations. For example,
the British Library Sound Archive has 140,000 recordings of more than 10,000
species of birds, mammals, insects and amphibians, donated by numerous
individual scientists and amateur recordists worldwide. Preserving such
large collections for the long term is a primary concern in the digital
age. While digitisation and digital preservation has many advantages over
analogue methods, the rate of technology change and lack of standardisation
is a serious problem for the world's major audio archives. Techniques to
reduce the risk of obsolescence include technology preservation, migration
or emulation. Another challenge is to make collections more easily and
widely accessible via electronic networks. On-line catalogues and access
to the actual sounds via the internet are already available for some collections.
[top]
[Oral communication]
Evolution of acoustic communication
in crickets: the case of the Eneopterinae
Tony Robillard and Laure
Desutter-Grandcolas
FRE2695 CNRS, Muséum
National d'Histoire Naturelle, Département Systématique et
Evolution, 45 rue de Buffon, 75005 Paris, France
E-mail: robillar@mnhn.fr;
desutter@mnhn.fr
The cricket subfamily Eneopterinae
is remarkably diverse for all characters involved in acoustic communication:
stridulatory apparatus, emitted signals and associated behaviors. This
diversity cannot be explained by current models of acoustic evolution in
crickets, which consider one stereotyped stridulum type evolving only by
multiple and progressive losses, with no possible diversification of the
structures. To study the origin and evolution of this diversity, we are
reconstructing phylogeny with cladistic methodology and using morphological
and molecular characters for specimens of almost every genus. The resultant
phylogenetic tree permits us to analyze evolutionary patterns of transformations
and to test hypotheses of evolution of acoustic devices in this clade:
the stridulum has been lost directly and several times independently, which
partly contradicts previous hypotheses on stridulum evolution. Also, morphological
syndromes of transformations are identified; they depict contrasted patterns
of evolution, including progressive or direct changes in forewing venation.
Evolution of calling songs is also under study. In relation to evolution
of stridulatory structure, evolutionary pattern of fundamental frequency
is also analyzed. A case of specialization toward high frequencies supporting
an hypothesis of adaptive radiation is documented in the Lebinthini tribe.
[top]
[Poster]
Study of a dolphin lower jaw
morphology and calculation of an echolocation hearing beam pattern
Vyacheslav A. Ryabov
Karadag Natural Reserve,
National Academy of Science of Ukraine, Kurortnoe, Feodosija 98188, Crimea,
Ukraine
E-mail: ryaboff@ukr.net
On the basis of recent works,
the lower jaw of a dolphin can be considered as a peripheral part
of the echolocation sound receiving apparatus, that conducts sonar echoes
up to the bulla. It is unclear, however, by what path the echo passes into
the lower jaw fat body, what structures of the lower jaw determine echolocation
hearing directivity and what mechanisms ensure to the dolphin a high accuracy
of sound source localization. The purpose of this work is to analyze the
possible function of the mental foramens as channels through which the
echo passes in the lower jaw fat body and to determine the role of these
channels and the skull in dolphin echolocation hearing directivity. The
morphology of the lower jaw and the modeling and calculation of the beam
pattern were studied in the Bottlenose Dolphin Tursiops truncatus.
Results indicate that the morphological structures of the lower jaw (left
and right halves) represent two hydro-acoustic receiving antennas of the
"traveling wave" (TWA) type. The mental foramens of the lower jaw represent
non-equidistant array of waveguide delay lines, and determine phase and
amplitude distribution of each antenna array. The beam pattern of echolocation
hearing was calculated according to the TWA model, with allowance for diffraction
of a flat sound wave on the rostrum structures in the area of the mental
channels. The beam pattern shape is naturally determined by echolocation
hearing functionality. The beam pattern of the left and right TWA models
cross one another in the nasal area, allowing an animal to execute a monopulse
analysis of an echo by a comparison method. At the same time, the "dead"
zone in the dorsal direction impedes hearing of a surface reverberation
of its clicks. The large area of the beam pattern crossing in the ventral
direction increases the reception of bottom reverberation that carry information
about water depth. The beam pattern is equally well adapted for both detection
and echolocation and for localization of pulse echoes. The calculated bearings
characteristic steepness reaches 0,4 - 0,7 dB per degree of angle.
[top]
[Symposium VI]
Modulation by steroid hormones
of a "sexy" acoustic signal in an Oscine species, the Common Canary Serinus
canaria
Fanny Rybak¹ and
Manfred Gahr²
¹ NAMC CNRS UMR 8620,
Université Paris-Sud, Bât. 446, 91405 Orsay Cedex, France
² Department of Developmental
and Behavioural Biology, Vrije Universiteit Amsterdam, The Netherlands
E-mail:
fanny.rybak@ibaic.u-psud.fr; gahr@bio.vu.nl
In Oscines, the song produced
by males is controlled at the cerebral level by a network of interconnected
nuclei sensitive to steroid hormones (testosterone and its estrogenic metabolite
estradiol). In the Common Canary Serinus canaria, song production
is correlated with a significant increase of testosterone levels in the
blood, just before and during the breeding season. The respective influence
of testosterone and estradiol on the structure of the Common Canary song
was studied by experimentally controlling blood levels of steroid hormones
in males and analyzing the consequent effects on acoustic parameters. For
that purpose, either testosterone plus an inhibitor of estradiol synthesis
or testosterone plus a placebo were implanted subcutaneously in 11 males.
A detailed acoustic analysis and a comparison between songs produced before
and after treatment revealed that steroid hormones controlled two parameters.
The duration of the sequences of syllables is influenced by testosterone
and estradiol: after implantation their duration increased and this effect
was significantly greater when estradiol synthesis was not inhibited. Moreover,
the repetition rate of syllables along sequences seems to be estradiol
dependent. The presence of receptors for testosterone and estradiol in
the brain neural pathway controlling song production strongly suggests
that the observed effects are mediated by steroid action at the neuronal
level. Since females of this species are especially responsive to certain
song parameters, including the repetition rate of syllables, it is possible
that females use the songs of the males to estimate the physiological state
of potential sexual partners.
[top]
[Poster]
Long distance vocal communication
by the Golden Lion Tamarin Leontopithecus rosalia: strategies of
emission and call degradation
Vera Sabatini and Carlos
Ramon Ruiz-Miranda
Universidade Estadual do
Norte Fluminense, Centro de Ciências e Biotecnologia, Laboratório
de Ciências Ambientais, Av. Alberto Lamego 2000, 28013-600 Campos
dos Goitacazes, RJ, Brazil
E-mail: versabatini@bol.com.br
Golden Lion Tamarins (GLTs)
emit long-calls used for intra- and inter-group communication. Because
these calls usually occur without visual contact, their message depends
on the acoustics characteristics of the signal and how it propagates through
the habitat. Our objectives were to ascertain if GLTs prefer some forest
strata when emitting long-calls and if the structure of long-calls is designed
for optimal transmission through the Atlantic forest of Brazil. We recorded
188 long-calls from 17 GLTs of four groups. For those and another 336 unrecorded
long-calls we noted the corresponding forest stratum, height above the
ground and habitat type. The results show that 85% of these calls were
emitted in or above the canopy. We performed playbacks of the calls
of five males and two females, emitted at 90 dB and 8,0 m height and recorded
at distances of 20, 40, 80, and 120 m in two areas of forest. The long-calls
attenuated with distance, their amplitude falling below background noise
by 120 m. At 80 meters, differential attenuation of the higher frequencies
(> 10 kHz) resulted in the loss of most syllables of the second phrase.
Low amplitude syllables of the first phrase were also lost at 80 m. At
40 m the phrase structure was similar to that of the source call. The highest
amplitude of the call was always in the first phrase, but appeared on different
syllables (and different values) at each distance. GLTs appear to maximize
the propagation of these calls by emitting them from the canopy. The two-phrase
long-calls seem "designed" for maximizing detection, because only some
elements of the first phrase are detectable at distances of 40 m. [Financial
support: CAPES, FENORTE and Margott Marsh-LBTF]
[top]
[Symposium V]
Birdsong and diversity in Amazonia:
using spectral analysis and playback to examine the role of song in allopatric
speciation
Nathalie Seddon and Joe
A. Tobias
Department of Zoology, Downing
Street, University of Cambridge, Cambridge, UK
E-mail: ns10003@cam.ac.uk
In Amazonia, suboscine birds
are extraordinarily diverse for reasons that remain unclear. To investigate
the role song may have played in generating this diversity, we examined
geographic variation in the songs of two species of suboscines, the Chestnut-tailed
Antbird Myrmeciza hemimelaena and the Scale-backed Antbird Hylophylax
poecilonota and one oscine passerine, the Moustached Wren Thryothorus
genibarbis in Noel Kempff Mercado National Park, Bolivia, at the southern
fringe of Amazonia. We recorded the songs of territorial birds in a natural
forest fragment (isolated for <10,000 years) and in nearby continuous
forest, then simulated secondary contact in these allopatric populations
using playback. Spectral analysis of songs revealed subtle differences
between populations in T. genibarbis and M. hemimelaena.
While vocal change is expected in the oscine (T. genibarbis) because
of song learning, it is more surprising in the suboscine especially given
the minor genetic differences between populations at the same sites found
in a previous study. Playback experiments indicated that (1) H. poecilonota
responded
with equal strength to playback of songs from all sites, whether local
or isolated, even when samples from Peru and Ecuador were included; (2)
T.
genibarbis responded more strongly to unfamiliar songs than to local
songs; (3) in contrast, M. hemimelaena responded more strongly to local
songs than to unfamiliar songs: i.e. birds from the forest island reacted
strongly to songs from their own population, but weakly to songs from nearby
continuous forest, and vice versa, while birds from the continuous forest
responded equally to local songs as to songs from both nearby and distant
sites in continuous forest. The results show that subtle shifts in song
structure in suboscine birds can occur relatively rapidly and that these
shifts may lead to reduced responsivity between populations, a first step
towards taxonomic divergence. This study provides first evidence in a suboscine
bird that changes in signal structure may occur during forest fragmentation,
and it underscores the potential role of this process in driving speciation
and generating avian diversity in Amazonia.
[top]
[Symposium VII]
A century of recorded wildlife
sounds
Patrick Sellar
The British Library Sound
Archive, 96 Euston Road, London NWI 2DB, UK
E-mail: patrick.sellar@compuserve.com
Recorded interviews of the pioneers
will reveal the extraordinary efforts required to capture the elusive sounds
of animals. Ludwig Koch made the first known sound recording of a bird,
a captive Shama Copsychus malabaricus, on a wax cylinder as long
ago as 1889, but it was in precisely 1900 that the sounds of wild birds,
Song Thrush Turdus philomelos and Common Nightingale Luscinia
megarhynchos song, were first recorded by Cherry Kearton in England.
Since then a vast number of recordings of sounds of wild birds and other
animals have been made all over the world, on equipment ranging from the
cumbersome apparatus for cutting wax discs to miniature modern-day digital
machines.
[top]
[Symposium VIII]
Application of information
theory reveals vocal learning in the White-vented Violetear Colibri
serrirostris (Aves, Trochilidae)
Maria Luisa da Silva¹,
Jacques Vielliard ² and Dora Fix Ventura ³
¹ Centro de Ciências
Biológicas, Universidade Federal do Pará, Campus Universitário
do Guamá, CEP 66075-110 Belém, PA, Brazil
² Laboratório
de Bioacústica, Instituto de Biologia, Universidade Estadual de
Campinas, CP 6109, 13083-970 Campinas, SP, Brazil
³ Laboratório
de Psicofisiologia Sensorial, Instituto de Psicologia, USP, Av. Prof. Mello
Moraes, 1721, 05508-010 São Paulo, SP, Brazil
E-mail: mluisa@ufpa.br;
jacques@unicamp.br;
dventura@usp.br
Hummingbirds (Aves, Trochilidae)
usually have high-pitched and rapidly modulated songs, resembling insect
sounds and therefore generally not calling the attention of human listeners.
Despite their colorful plumage seemingly representing a sophisticated visual
communication system, hummingbirds use song for the biological function
of species-specific recognition. These songs are as complex, in certain
species, as those of Oscines, and they may include population and individual
variations, indicating vocal learning. The song of the White-vented Violetear
Colibri
serrirostris, a case in point, is composed of an individually variable
sequence of discrete notes. The song structure can be analyzed, after sonographic
identification of the note types, using mathematical tools to characterize
and compare the distribution of note types. In our recordings of 14 different
individuals from 10 localities, each singer presented its own repertoire
of different note types. Although the individual repertoire is small, consisting
of 3 or 4 note types, these notes are uttered in peculiar individual sequences.
To define the structure and organization of this species' song, we calculated
the first and second order entropy to establish individual sequences measurement,
and the results were synthesized through cluster analysis. We found great
inter-individual variation in note structures and repertoire sequences.
Neighboring males can share some note types, but they emit them in different
sequences. This indicates the existence of a vocal learning process through
model imitation, besides a creative mode responding for the individual
variation of sequences. Such patterns of vocal learning are poorly known
and must be better studied.
[top]
[Symposium II]
Tonal vocalizations in a noisy
environment: an approach to their semi-automatic analysis and examples
of its application
Christina Sommer and
Roger Mundry
Institute of Biology, Department
of Behavioural Biology, Free University of Berlin, Haderslebener Str. 9,
12163 Berlin, Germany
E-mail for contact: rmundry@zedat.fu-berlin.de
Many species of birds and mammals
utter vocalizations with a more or less tonal structure, that is calls
that exhibit an emphasised fundamental frequency and presumably can
be sufficiently described by measures of its shape. Such vocalizations
might be of particular importance for communication over long distances
and/or in noisy environments, when subtle variations of signal structure
are likely to be severely degraded from the sender to a receiver. Researchers
analysing such vocalizations often face the same problems as presumably
do animal receivers, in that the recorded signals can be heavily masked
by environmental noise and, furthermore, degraded through the distance
between the calling subject and the recording equipment. In addition, analysis
of tonal vocalizations using available software usually allows for reliably
measurement of only a few parameters that do not necessarily depict the
structure of the vocalization in sufficient detail. Here we present an
analytic approach and corresponding (free) software, designed to cope with
these problems, combining algorithms that detect calls and their fundamentals
within (noisy) spectrograms and provide detailed measurements of the fundamental
frequencies' contours. In the presentation we will give descriptions of
various robust parameters that measure the contours of tonal vocalizations
in detail. In addition, we will present quantifications that permit us
to assess the reliability of an analysis. The software itself includes
a batch mode that allows the user to analyse any number of spectrograms
automatically, but it also may be run interactively, enabling the user
manually to adjust call detection. It includes an optional frequency-dependent
noise filter that may enhance the signal-to-noise ratio. Finally, we will
present some results of exemplary analyses of bird calls. In addition,
we will discuss the possible importance of contours of tonal calls in long-distance
communication and in noisy environments.
[top]
[Symposium VIII]
Similarity measurements between
spectrographic images of bird song notes
Nilson E. Souza-Fº,
Maria Luisa da Silva 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
A spectrogram is an image that
visually represents the quantity of the energy of a signal in reference
coordinates of time and frequency. Starting from this definition, we suggest
a new approach to calculate the similarity between two bird song notes
(uninterrupted units of sound) using their spectrographic images. The measurement
consists of a very well known technique in digital image processing (DIP)
used for matching images, the Cross Correlation Normalized (CCN) or "Template
Matching" method. This technique was applied to songs of the Rufous-bellied
Thrush Turdus rufiventris, that had previously been analyzed by
Maria Luisa da Silva. The specific song is composed of whistles and trills
of median pitch. Phrases are uttered in long sequences of regularly spaced
notes. An image bank composed of sonograms of T. rufiventris song
sequences was submitted to CCN calculus in order to measure similarities
between notes. This new usage of the method in bioacoustical analysis can
be called Spectrographic Image Template Matching (SITM). Additional tests
are yet needed to establish the efficiency of this promising SITM
technique.
[top]
[Poster]
Compact and user-friendly ultrasound
acquisition systems optimised for field recording
Raimund Specht
Avisoft Bioacoustics, Hauptstr.
52, D-13138 Berlin, Germany
Web page: www.avisoft.info
E-mail: raimund.specht@avisoft.de
Until recently, opportunities
for recording ultrasonic animal vocalizations in the field were limited.
The commonly used time-expansion bat detectors have a low dynamic range
(8 bit only) and do not support continuous recording over longer periods
of time. High-speed tape recorders are bulky and very expensive. High-speed
PCMCIA data acquisition cards installed in laptop computers suffer from
the fragile connectors and the lack of anti-aliasing filters. For these
reasons, Avisoft Bioacoustics designed specialized hardware as a solution
for mobile ultrasound recording. New compact devices (56 by 35 by 140 mm)
integrate an adjustable pre-amplifier, a peak-level meter, a high-speed
16-bit A/D converter with anti-aliasing filter (sigma-delta type), an acoustic
monitor for making the ultrasound audible to the human ear, a trigger button
and a rugged USB interface for reliable operation from a laptop. Various
ultrasound microphones can be attached via extension cables. The accompanying
recording software provides a real-time spectrographic display and a pre-trigger
recording mode. The trigger button on the recording device enables the
user to remotely control the hard-disk during recording sessions, while
the laptop is safely stored in a backpack. Alternatively, the ultrasound
microphone and laptop can be deployed at a fixed place in the field. For
that application, the recording software can be configured to capture sounds
in a sound-activated mode. Additionally, 4-channel devices are available
that are not limited to field recording applications but could also benefit
laboratory recording from their ease of use, especially because no device-specific
drivers need to be installed.
[top]
[Symposium VI]
Vocal mechanisms in birds and
bats: a comparative view
Roderick A. Suthers
School of Medicine and Department
of Biology, Indiana University, Bloomington, IN 47405, USA
E-mail: suthers@indiana.edu
Despite their very different
vocal organs, both songbirds and echolocating bats have attained highly
developed, specialized vocal abilities. Echolocation places a premium on
directional sonar pulses with short wavelengths and high repetition rates.
Bird song, on the other hand, is often characterized by a wide range of
spectral and temporal patterns at frequencies about an order of magnitude
lower than those in bat sonar signals. The morphology of the mammalian
and avian vocal organ is strikingly different. The larynx of echolocating
bats is at the cranial end of the trachea, whereas the songbird vocal organ,
the syrinx, resides in an air sac at the junction between trachea and bronchi.
This difference in location has important implications for how the acoustic
signal generated in the vocal organ is filtered or modified by the vocal
tract or other structures. Other important differences include the thin
membranes on the vocal folds of the bat larynx and the bipartite structure
of the songbird syrinx that contains two sound sources under independent
lateralized motor control. Despite these obvious differences, recent studies
on the source and spectral properties of sound generated in the avian syrinx
provide interesting parallels with the mammalian larynx. Both these groups
of animals face similar problems in synchronizing the motor pattern that
gates phonation with that controlling sound frequency. This coordination
becomes increasingly critical as call repetition increases. The sonar pulse
repetition rate in the terminal buzz of a bat is much higher than the maximum
syllable repetition rate in trilled phrases of songbirds. In bats
both of these functions are controlled by the same laryngeal muscle, whereas
in songbirds separate syringeal muscles control the timing and fundamental
frequency of the vocalization.
[top]
[Symposium IV]
From birdsong to speech: an
introduction
Dietmar Todt
Institute of Biology, Department
of Behavioral Biology, Free University of Berlin, Haderslebener Str. 9,
12163 Berlin, Germany
E-mail: todt@zedat.fu-berlin.de
Human speech is definitely a
unique accomplishment. Nevertheless, it shares a number of characteristics
with other systems of communication, and investigators have thus compared
it to birdsong or the vocal signaling of nonhuman primates, for example.
Interesting parallels concern especially the ontogenetic development of
song and language. Both singing and speaking, for example, have to be learned
in order to achieve the normal species typical properties. Such learning
relies on auditory perception, subsequent memorization and imitation of
sound patterns, that is, perceptional processes precede the production
of vocal material. Language acquisition as well as song learning is best
achieved early in life, and vocal expertise is successfully reached only
at particular stages of development, in which vocal practice plays an essential
role. Several mechanisms help young individuals to deal with various challenges
to signal learning. In birds, such mechanisms allow for selection among
potential learning stimuli and at the same time facilitate pattern memorization.
The acquisition of song is impressive when considered in a framework of
functional aspects. In functional terms, it provides a male bird with a
repertoire that serves both mate attraction and effective territory defense.
With respect to the latter function, it prepares for specific vocal interactions
among males that previously had the chance to learn similar songs and thus
share parts of their vocal repertoires. In conclusion, song learning is
really outstanding in the animal kingdom. Here, it is a unique achievement
that clearly deserves to be compared to the genuinely human accomplishment
of language acquisition. Specific differences aside, astounding parallels
can be found also in how a human and a particularly virtuous bird like
the Common Nightingale Luscinia megarhynchos treat exposures to
many different sound patterns or songs. With these properties as a reference,
bird song learning is an excellent biological model for memory research
and also an appropriate system for the study of evolutionary strategies
of problem solving in a very successful class of organisms.
[top]
[Symposium III]
Individual differences in infant
Guinea Pig Cavia porcellus isolation whistles and lack of maternal
recognition
Rosana Suemi Tokumaru¹,
Patrícia F. Monticelli² and César Ades²
¹ Departamento de Psicologia
Social e do Desenvolvimento, UFES, Campus Goiabeiras, Av. Fernando Ferrari,
29060-900 Vitória, ES, Brazil
² Departamento de Psicologia
Experimental, USP, Av. Prof. Mello Moraes 1721, 05508-010 São Paulo,
SP, Brazil
E-mail: rstokumaru@yahoo.com.br
When separated from their mother
and other group members, Guinea Pig Cavia porcellus pups emit distinctive,
high-pitched whistles. Individual recognition of such isolation calls by
the mother could play an important role in facilitating reestablishment
of contact. To determine if whistles are individually distinctive, we recorded,
in a first experiment, whistles of isolated 8 to 10 day-old pups (n = 6),
and subjected their acoustical parameters to discriminant analysis. The
results of reclassification accuracy were higher than random assignment,
thus indicating the existence of individual differences. In a second experiment,
using a discrimination procedure, we examined the possibility that recognition
of her own pup vocalizations depends on the mother's previous experience.
Playbacks of the whistles of a female's own pup were paired with access
to her pups while playbacks of another, unfamiliar pup's whistles were
not followed by pup presentation. There were no differences, either in
mothers' approach behavior or general activity between own and other pup
playback trials. Reduced risks of pup injury by other members of the group,
low maternal motivation for maintaining contact with offspring, and the
existence of a short-distance, olfactory-mediated mother-pup recognition
system may account for the lack of recognition of isolation whistles.
[top]
[Symposium VII]
Establishing a bioacoustic
collection for the Neotropics: present and future of the "Arquivo Sonoro
Neotropical"
Jacques Vielliard
Laboratório de Bioacústica,
Instituto de Biologia, Universidade Estadual de Campinas, CP 6109,
13083-970 Campinas, SP, Brazil
E-mail: jacques@unicamp.br
The Neotropical Sound Archive
("Arquivo Sonoro Neotropical" - ASN) was created in 1978 as a result of
four expeditions undertaken by the author in Brazil from 1973 to study
natural bird communities for the Brazilian Academy of Sciences. Because
of the necessity of knowing bird species' voices for ornithological field
research and of the lack of reference recordings, except for the work of
a few amateurs, I initiated a national sound archive. This objective was
achieved when the Universidade Estadual de Campinas (UNICAMP) invited me
to found a Bioacoustics Laboratory. Since then, the archive has grown rapidly,
thanks to the numerous field expeditions made with support from the Brazilian
National Research Council (CNPq) and through the contributions of
students and collaborators. Such an archive needs the collaboration of
all interested people and should be associated with a teaching and research
institution. The Bioacoustics Laboratory now offers technical assistance,
graduate and post-graduate courses, media publications and every possible
support to answer any query. This policy helps promote our aims of enhancing
public and governmental awareness of nature preservation issues, and congregating
contributing recordists. In spite of cyclical financial restrictions, the
Laboratory and Archive have remained active without interruption since
their creation a quarter of century ago. A source of pride is the fine,
ongoing collaboration that has contributed to the Archive's scientific
value and its position among the world's major natural sound archives.
Today, we are pleased to announce that the more than 25.000 fully-documented
cuts will soon be transferred to high-definition digital media (DVD) and
incorporated into a large on-line scientific database created by the São
Paulo state research agency FAPESP. Although it implies new investments,
transfer to digital media is the solution for sound archives since it requires
cheaper equipment and recording media, while facilitating conservation
(especially in tropical climates) as well as cheaper and easier copying.
The future of wildlife sound archives is renewed by digital technology,
but the fundamental rules for valuable scientific recordings remain the
same: accurate technical standards and rigorously documented data.
[top]
[Symposium VIII]
Complex communication signals:
the case of bird songs
Jacques Vielliard
Laboratório de Bioacústica,
Instituto de Biologia, Universidade Estadual de Campinas, CP 6109,
13083-970 Campinas, SP, Brazil
E-mail: jacques@unicamp.br
Bird species, particularly those
with learning capacities, show a tendency to increase the complexity of
their acoustic communication systems. This can be accomplished through
an increase of their repertoire (various song types, numerous calls for
diverse functions) or of the structural complexity of their sound signals.
Taking into account only the functional song that manifestly carries species-specific
recognition information, we found a great variety of complex structures:
multiple stereotyped phrases, regional dialects, high number of sound units,
versatile sequencing of notes, and individual variations. Complex sound
structures can be described precisely, but such descriptions give overwhelming
details and overlook the general picture. Difficulties arise when two such
complex structures are to be compared, for instance in determining how
similar are the songs between two populations of a species with geographical
variations, or between two neighbors of a species with individual variations.
And how should species with differing structural organization of their
songs be compared? A few examples, taken from the Brazilian avifauna, will
illustrate some of these problematic situations.
[top]
[Symposium III]
Individual acoustical characteristics
of free-ranging and captive Yangtze Finless Porpoises Neophocaena phocaenoides
asiaeorientalis
Kexiong Wang¹, Ding
Wang¹ and Tomonari Akamatsu²
¹ Institute of Hydrobiology,
the Chinese Academy of Sciences, Wuhan, Hubei 430072, China
² National Research
Institute of Fisheries Engineering, Ebidai, Hasaki, Kashima, Ibaraki 314-0421,
Japan
E-mail: wangd@ihb.ac.cn
Sounds of eight individuals
(six males and two females) of Yangtze Finless Porpoises Neophocaena
phocaenoides asiaeorientalis were recorded individually in Shishou
Baiji Semi-natural Reserve, Hubei, China, in June 2002. Individual sounds
of five animals were recorded in open waters, and the other three individuals
were recorded in net-circles. Additionally, individual recording of sonar
signal events, body movements, swimming speed and depth of three captive
Yangtze Finless Porpoises (one male and two females) were conducted using
an acoustic data logger (W20-A, Little Leonardo, Tokyo, Japan) and an acceleration
data logger (PD2GT, Little Leonardo, Tokyo, Japan) in Baiji Dolphinarium,
Wuhan, China, in November 2002. The data logger system was attached by
a suction cup (Canadian Tire Corp.) on the animals for more than 40 hours.
The acoustic data logger could record ultrasonic signals with less contamination
of low frequency noises by a 100-kHz high-pass filter. Differences of click
emission rate were found among all the animals. The circadian rhythms of
respiration, swimming, and sound production of captive animals were documented.
Correlation between body movement and sonar pulse structure was also recognized.
[top]
[Poster]
Why is a smile audible? A new
hypothesis on the evolution of sexual behaviour and voice
Vanessa Zacher and C.
Niemitz
Department of Human Biology,
Freie Universität Berlin, Albrecht-Thaer-Weg 6, 14195 Berlin, Germany
E-mail: zacher@zedat.fu-berlin.de;
cniemitz@zedat.fu-berlin.de
It is an everyday experience
that a smiling face can be detected with some certainty by just listening
to a person. This may be caused by the side effects of smiling, such as
an alteration of the shape of the vocal tract. In order to examine which
acoustic parameters are different in a smiling voice, we measured the differences
between smiling and neutral speech. An earlier experiment showed that people
could, with some certainty, identify a smiling speaker by listening. The
subsequent analysis showed that smiling has an effect on most acoustic
parameters. It raised the maximum of the basal formant as well as the average
frequency of the second and third formants. More than 20 other tested parameters
were significantly different between smiling and non-smiling voices, including
differences in duration, differences in ways of articulating vowels, and
differences between sexes. These highly complex differences can not merely
be a secondary effect of passive deformations of the vocal tract through
smiling. Cerebral control of such unintentional parameters of communication
must have a genetic basis established by selective forces. Human courtship
behaviour is mostly done in privacy, often in conditions of poor illumination.
This may be the reason for so many significant differences between the
smiling and the non-smiling voice.
[top]
| Venue Information: | Accommodation | Location | Street-wise | Touristic Information |
Last modification: Jul, 16, 2003