Crespo, E.G., Oliveira, M.E., Rosa, H.C., & Paillette, M. (1989). Mating calls of the Iberian midwife toads Alytes obstetricans boscai and Alytes cisternasi. Bioacoustics 2(1): 1-9
Abstract
The mating calls of the Iberian midwife toads, A. o. boscai and A. cisternasii show clear differences. We calls of A. o. boscai have a shorter duration (104.8 ms) and a lower fundamental frequency (1.33 kHz) than those of A. cisternasii (172.0 ms and 1.45 kHz), between 12° and 16°C. In both species signal duration was found to be influenced by temperature.
Gautier, J.-P. (1989). A redrawn phylogeny of guenons based upon their calls - biogeographical implications. Bioacoustics 2(1): 11-21
Abstract
A phylogeny of guenons was drawn up from the analysis of the acoustic structure of their cohesion, contact and alarm calls, as well as of the loud calls of the adult males. The plesiomorphic or anamorphic state of every acoustic parameter retained was inferred from comparisons with calls given by papionines and/or colobines. A cladistic method was used for analysing a matrix of species by character.
The proposed phylogeny separates guenons into two groups: the one includes all forest-living arboreal forms, the other most of the terrestrially-adapted species. The latter, together with C. nigroviridis, which lie close to the origin from which all guenons diverged, share a relatively primitive position, while the arboreal species are the most derived living representatives of the taxon. Quite reliable interspecific affinities are found among arboreal forms, while there are some inconsistencies for the more primitive species. Such results suggest that cercopithecines would have undergone a radiation from more or less open habitats into forests, the evolution proceeding from large-bodied, partly-terrestrial forms to smaller arboreal ones.
Aubin, T. & Brémond, J.C. (1989). Parameters used for recognition of distress calls in two species: Larus argentatus and Sturnus vulgaris. Bioacoustics 2(1): 22-33
Abstract
Distress calls are signals effective over a long distance. They are well known to evoke interspecific reactions. We suggest that the interspecifity phenomenon results from the use of similar laws of decoding by the species concerned. These laws must take into account the transmission channel which always has a great influence on long-range communication. We tested our hypothesis by broadcasting simplified synthetic calls to two species of birds: the herring gull and the starling. The various calls differed in terms of frequency modulation (FM). Two main conclusions emerged from this series of tests:
1) The parameters used for recognition are not sophisticated: a simple slope applied to a carrier frequency that corresponds to the acoustic shape of a distress call is sufficient to infer a distress meaning to the signal. The basic rules are the same for the gull and the starling, with differences only in the acceptance level of the species.
2) The system of recognition is based upon parameters not altered by the environment: the birds make use of the slow frequency modulations (FMI). In contrast, the fast frequency sweeps (FMII) which are modified during propagation do not seem to be utilized. The use of these characteristics of distress calls for recognition allows interspecifity and maximum efficiency for propagation over long distances.
Nowicki, S., Mitani, J.C., Nelson, D.A. & Marler, P. (1989). The communicative significance of tonality in birdsong: responses to songs produced in helium. Bioacoustics 2(1): 35-46
Abstract
“Pure tones” are a distinctive acoustic feature of many birdsongs. Recent research on songbird vocal physiology suggests that such tonal sounds result from a coordinated interaction between the syrinx and a vocal filter, as demonstrated by the emergence of harmonic overtones when a bird sings in helium. To investigate the communicative significance of vocal tract filtration in the production of birdsong, we used field playback experiments to compare the responses of male swamp sparrows Melospiza georgiana to normal songs and those same songs recorded in helium. We also measured responses to pure tone songs that had been shifted upward in frequency to match the average spectra of those songs with added harmonics. Male sparrows were significantly more responsive to the playback of normal songs than to either helium songs with added harmonics or frequency-shifted pure tone songs. Songs with harmonics retained a high degree of salience, however. We conclude that explanations for the occurrence of tonal sounds in birdsongs must consider perceptual attributes of songs as communicative signals, as well as problems of song production and transmission.
Telford, S.R., Dyson, M.L. & Passmore, N.I. (1989). Mate choice occurs only in small choruses of painted reed frogs Hyperolius marmoratus. Bioacoustics 2(1): 47-53
Abstract
In two-choice discrimination experiments females of Hyperolius marmoratus preferred the calls of lower frequency of the pair of stimuli. This preference was not shown in mating patterns observed in natural choruses, but is when females are phonotactically orienting in small choruses in an experimental enclosure. With an increase in chorus size, the mating pattern shifts from size-based, non-random (with some evidence of size-assortative) mating to random mating. This is the first time that frequency-based mate-choice by female anurans has been associated with chorus size, and hence with the sonic complexity of the acoustic environment.
Menne, D. (1989). Digital filters in auditory physiology. Bioacoustics 2(2): 87-115
Abstract
In auditory research, the manipulation of signals by filtering with analog electronic filters plays an important role. Recently, digital filters that compute signal modifications in real-time became available. They can mimic all functions of analog filters, and additionally make possible new experimental concepts.
This tutorial paper introduces the concept of digital filters by using analogies from acoustics. Even complex acoustical environments can be simulated with digital filters, as they allow the programming of almost arbitrary frequency and phase responses.
Harrington, F.H. (1989). Chorus howling by wolves: acoustic structure, pack size and the Beau Geste effect. Bioacoustics 2(2): 117-136
Abstract
A variety of structural parameters were measured from wolf choruses recorded in the Superior National Forest, Minnesota, USA. Mean duration of 60s did not vary with pack size or composition. Packs replied to simulated howling after an average of 40s, often interrupting the stimulus howls. Choruses began with simply-structured howls, which became increasingly modulated as the chorus progressed. Little difference in mean fundamental frequency or other howl parameters was found among the choruses from packs of various sizes and compositions. In particular, choruses produced by single adult pairs did not differ from those of larger packs accompanied by pups. The lack of relationship between chorus parameters and pack size or composition indicates there is little useful information concerning a pack's size to be found in its chorus howling.
The observation that chorus howling by adult pairs is often perceived as that of larger groups with pups suggests that chorus structure has evolved to exaggerate the apparent size of the pack, especially those newly-established or otherwise reduced in number. If so, wolf howling choruses may represent a mammalian example of the Beau Geste effect, made particularly viable because of the relative immunity of the signal to probing.
Adret-Hausberger, M. (1989). The species-repertoire of whistled songs in the European starling: species-specific characteristics and variability. Bioacoustics 2(2): 137-162
Abstract
Observations of European starlings in France, Germany and Australia reveal surprising high similarities in the individual repertoires of whistled songs. The structure of the whistles enabled us to recognize a number of categories, in which some species-specific themes were found everywhere. They appear with the same general characteristics and variation ranges in all populations.
There seems therefore to be a basic species-specific repertoire common to all males who have also a number of additional individual themes which characterize each male in its colony. These individual themes show also common characteristics in the different populations. The results suggest that a mechanism has evolved which canalizes the patterns to be learned. The existence of such a universal innate species-specific repertoire has also to be related to functional aspects and to the complicated dialects found in this species.
Wilkinson, R. (1990). Vocal behaviour and call development in the bullfinch (Pyrrhulla pyrrhulla). Bioacoustics 2(3): 179-197
Abstract
A sonographic analysis of the vocalizations of bullfinches Pyrrhula pyrrhula is presented and their behavioural contexts and functions noted. The vocal repertoire of the bullfinch is compared to that of other finches with particular attention to repertoire size and sexual specificity; the repertoire of 14-17 vocal categories is comparatively greater than that of most carduelines and the majority of vocalizations were given by both sexes. The development of nestling, fledgling and some adult calls is described. Early vocal ontogeny in the bullfinch was similar to that previously described for the chaffinch. The earliest recorded calls of nestling bullfinches showed a single fundamental. The independent use of two sound sources became apparent on the second day after hatching and the major elements of the three best studied call types were all derived from the lower fundamental of the nestling begging call.
Campbell, D.J. (1990). The new sound trap, and observations on the migratory and acoustic behaviour of the field cricket Teleogryllus commodus (Walker). Bioacoustics 2(3): 199-207
Abstract
A new sound trap for capturing male and female crickets attracted to the calling song of the male is described. Major advantages of the trap are its portability and effusiveness. It was designed to operate in conjunction with a previously described cricket-song generator. The trap is compared with other designs and the acoustic and migratory behaviour of crickets revealed by sound trapping are discussed.
Palestrini, C., Zunino, M. & Zucchelli, M. (1990). Sound production in the larvae of Geotrupes spiniger (Marsham)(Coleoptera: Geotrupidae). Bioacoustics 2(3): 209-216
Abstract
Thin paper focuses on sound production in the larvae of Geotrupes spiniger (Marsham) (Coleoptera: Geotrupidae). A single stimulatory apparatus was identified and then analysed from a structural point of view. Sound was studied using spectrography and results included a quantitative analysis with characterizing physical parameters. Results highlight the need to study stridulation in Geotrupidae more in detail, to improve our understanding of its evolutionary and biological meaning.
Stoddard, P.K. (1990). Audio computers - theory of operation and guidelines for selection of systems and components. Bioacoustics 2(3): 217-239
Abstract
Computers are available that can store, synthesize and replay sounds using digital techology. I describe the major components of audio computers, the principles of digital sound accquisition and playback, and information and caveats for scientists interested in acquiring an audio computer system for their own use. A tutorial on analog filter application also included as well as a diagnostic procedure and a buyer's check list.
Torricelli, P., Lugli, M. & Pavan, G. (1990). Analysis of sounds produced by male Padogobius martensi (Pisces, Gobiidae) and factors affecting their structural properties. Bioacoustics 2(4): 261-275
Abstract
In this paper a detailed analysis of the physical structure of sounds produced by male Padogobius martensi is reported. Sound production occurs during courtship and inter-male agonistic encounters. Both aggressive and courtship calls are made up of rapidly repeated pulses, with a pulse repetition rate decreasing through the course of the emission. By means of computerized analysis, the pulse repetition rate, its modulation and sound duration were determined. The water temperature was found to exert a marked and significant effect on the above parameters. In particular, the temperature directly affects the pulse rate and its decrease through the course of the emission (i.e. frequency modulation) and inversely affects sound duration. By contrast, size of the calling animal does not significantly influence the sound parameters considered. Aggressive sounds last longer and have a lower pulse repetition rate than the courtship sounds. Moreover, aggressive sounds appear more variable than the courtship ones as far as pulse rate and duration are concerned.
Thorsten Elfstrom, S. (1990). Individual and species-specific song patterns of rock and meadow pipits: physical characteristics and experiments. Bioacoustics 2(4): 277-301
Abstract
The songs of Anthus spinoletta littoralis and A. pratensis, in sympatric populations in SW Sweden were recorded, analysed in sound spectrographs and tested in the field. The purpose was to investigate: a) if the strophes are species specifically and individually distinct and, if so, whether pipits are able to make such distinctions; b) if the species-specific and individual-specific patterns are concentrated in different sections of the song and, if so, whether the species-specific section transmits individual-specific information and the individual-specific section transmits species-specific information as well.
The basic structure of the syllables in the terminating section of the strophe was found to be intraspecifically stereotyped, but varied between the two species. Replay experiments showed that territorial males could discriminate between con- and heterospecific strophes and this ability persisted when the terminating section of the strophe was replayed alone. The terminating part of the strophe did not seem to transmit individual-specific information to conspecific males. On the other hand, the basic structure of the syllables in the first section of the strophe was intraindividually stereotyped but varied between most conspecific males. Playback experiments showed that a territorial male could discriminate his neighbours' song patterns and this ability remained intact when the introductory phrase of the strophe was replayed alone. Both song pattern and position were necessary properties of the identifying signal in these pipits. But the introductory phrase of a total stranger did not seem to transmit unambiguous species-specific information to conspecific males.
Dahlquist, F.C., Schemnitz, S.D. & Flachs, B.K. (1990). Distinguishing individual male wild turkeys by analyzing vocalizations using a personal computer. Bioacoustics 2(4): 303-316
Abstract
The Department of Wildlife Sciences, New Mexico State University, and the New Mexico Wild Turkey Federation have developed a personal computer system for distinguishing individual male wild turkeys. The system determines census and distribution data for the State endangered subspecies of Gould's wild turkey Meleagris gallopavo mexicana. Since the bird is endangered, more conventional means such as capture, tagging and telemetry are not allowed. Programming provides software for acquisition of data, production of spectrograms and oscillograms, cross correlation and auto correlation and a data management capability. During the spring mating seasons of 1987 and 1988 field recordings were made of gobbling in a limited area of SW New Mexico. The data was processed by the computer and revealed a total of 9 recorded individual gobblers for 1987 and 11 for 1988. It also showed that 4 of the birds recorded in 1987 were also recorded in 1988, and movement data ranged from 1.6 to 11.2 kilometers. The system has proven to be a valuable tool in determining census data and movement information on the male Gould's wild turkey in SW New Mexico. Plans for future use are for the differentiation of subspecies, identification of individual females and the analysis of specific turkey calls.
Brown, L.J. & Bailey, E.D. (1990). Duration discrimination in Northern bobwhite quail. Bioacoustics 2(4): 317-326
Abstract
We examined the ability of northern bobwhite quail Colinus virginianus to discriminate along the duration dimension because of its suspected importance in their ability to identify individual covey members. If quail are using variability along this dimension to identify individuals we would expect their auditory resolving powers to be sufficiently refined in that dimension to make appropriate discriminations. Three 2-year old male bobwhite quail were trained using a positive reinforcement technique to discriminate between a 1000 Hz standard (correct) tone 600 ms in duration (100 ms rise/fall time) and a 1000 Hz comparison tone 300 ms in duration (also 10 ms rise/fall time). Quail were then required to discriminate between pairs of tones in which the duration of the comparison tone was progressively increased from 400 ms to 590 ms. Because of the categorical nature of the analysis we concluded that the two tones must differ in duration by 20 ms or more if they are to be discriminated correctly. Our study has shown that bobwhites are able to detect a 3% difference in duration around a standard tone 600 ms in duration, which compares favourably with results obtained from earlier studies with parakeets Melopsittacus undulatus and pigeons Columbia livia. Such a finely tuned duration discrimination ability also suggests that it is possible bobwhites may be using individual variability along the duration dimension of the separation call to identify individual covey members.