Newton-Fisher, N., Harris, S., Green, P. & Jones, G. (1993). Structure and function of red fox Vulpes vulpes vocalisations. Bioacoustics 5(1-2): 1-31
Abstract
A sonographic analysis of the structure of fox vocalisations, based on 512 adult and 73 cub vocalisations obtained from archive recordings, was combined with field data on the vocal behaviour of an urban fox population. Calls were described quantitatively by six variables: duration, lowest and second lowest frequency bands (from sonagrams), highest and second highest peak frequencies (from power spectra) and the number of components. They were separated into 20 call types, eight of which were cub vocalisations. Call types were used singly or in combination, and some gradation between particular call types was apparent. Hypotheses regarding call function were generated based on the matching of acoustic properties with their seasonal occurrence and the socioecological pressures acting on foxes at different times of the year. Calls that were structurally suited to agonistic and contact functions were found to be significantly more common during the winter, the time of mating and dispersal, when foxes move over greater areas.
Espmark, Y.O. & Lampe, H.M. (1993). Variations in the song of the pied flycatcher within and between breeding seasons. Bioacoustics 5(1-2): 33-65
Abstract
The main objectives of this study were to provide a thorough description of the advertising song in the male pied flycatcher Ficedula hypoleuca and examine the complexity of the song and its variability within and between breeding seasons by qualitative and quantitative analyses of its structure.
Songs were recorded from 117 males in central Norway in one or more of the three stages of the breeding season: before pairing, during nest building, and in the laying/brooding stage. Eight males were recorded both before and after pairing, and 13 males were recorded in two consecutive years. Spectrographic analyses were based on 25 consecutive song strophes per male.
When the males became mated their song changed in a number of ways: in addition to reduced singing activity, the number of figures and figure types in the song strophe became fewer at the same time as the song strophe became shorter. There was also a tendency towards increasing song versatility and decreasing repertoire size. Individual males differed significantly in all tested variables, as did the two categories unpaired and paired males.
From one year to the next the song of the male pied flycatchers became more versatile, the number of unique figures increased and there was a tendency towards increasing repertoire size. Changes in the other song variables were insignificant, although considerable individual variations were recorded. New song figure types and song types appeared between years in individual males of any age. This may indicate that song learning continues into adulthood, or that subsets of early memorized songs are used in different years.
Miller, L.A. & Treat, A.E. (1993). Field recordings of echolocation and social signals from the gleaning bat Myotis septentrionalis. Bioacoustics 5(1-2): 67-87
Abstract
We recorded echolocation and ultrasonic social signals of the bat Myotis septentrionalis. The bats foraged for insects resting on or fluttering about an outdoor screen to which they were attracted by a 'backlight'. The bats used nearly linearly modulated echolocation signals of high frequency (117 to 49 kHz) with a weak second harmonic. The orientational signals from patrolling bats were about 2.4 ms in duration and occurred at a repetition rate of about 18 Hz. The signals used by bats as they approached the screen were of shorter duration (0.72 ms) and occurred at higher rates (33.8 Hz). We registered one feeding 'buzz'. We recorded social signals when two bats patrolled the hunting area. The social signals were characterized by their longer durations (6 ms), lower frequencies (70 to 30 kHz), and curvilinear sweeps. We calculated the source levels of orientational and social signals using the differences in arrival times at three microphones in a linear array. The source levels were on average 102dB peSPL at 10 cm. We could not calculate source levels of the signals used by bats as they approached the screen at close range, but these signals were much weaker (about 65d8 peSPL at the microphone).
Heller, K.-G. & Achmann, R. (1993). The ultrasonic song of the moth Amyna natalis (Lepidoptera:Noctudidae: Acontiinae). Bioacoustics 5(1-2): 89-97
Abstract
In Malaysia, males of the noctuid moth Amyna natalis were observed producing a continuous ultrasonic song of high intensity (about 102 dB SPL measured at a distance of 10cm). The frequency spectrum of the sound impulses had its peak between 60 and 80 kHz. During song production the animals were perching on plants and moving their wings up and down quickly. Simultaneously, by twisting the wings it seems likely that a male-specific “bubble'' in the forewing functions as a tymbal, resulting in sound production.
Ruiz-Miranda, C.R., Szymanski, M.D. & Ingals, J.W. (1993). Physical characteristics of the vocalizations of domestic goat does Capra hircus in response to their offspring's cries. Bioacoustics 5(1-2): 99-116
Abstract
The vocalizations emitted by adult female domestic goats in response to their offspring's bleats were recorded, and sonograms were made and analyzed. The calls were segmented, atonal, and broad banded between 200 and 4,840 Hz. The energy was concentrated, on the average, around 1,258 Hz, a frequency close to the optimal hearing capabilities of the species. There were statistically significant individual differences for duration, number of segments, number of harmonics, peak frequency and fundamental frequency. Furthermore, using a discriminant function analysis we were able to correctly assign 76% of the calls to the individuals that emitted them. We concluded that the does have individually distinctive vocalizations, and that the physical characteristics of the bleats allow for locatability and ease of detection of the signal. Therefore, it is possible for the kids to be able to recognize and locate their mothers on the basis of auditory cues.
Tschuch, G. (1993). Sound production in Mutillid wasps. Bioacoustics 5(1-2): 123-129
Abstract
The stimulatory organs of male and female Mutillid wasps are similar and occur between their 3rd and 4th abdominal termites. The three investigated species, Smicromyrme rufipes, Dasylabris kozlovi and Mutilla marginata, possess files with different 'ripple' distances that are species specific (2.5 to 5.4 micrometres). The sonogram of the distress calls from female M. marginata shows the ripple frequency with low amplitude rising in the first 20 milliseconds from 1.2 to 1.5 kHz and then falling back in the following 20 milliseconds. The main sound energy occurs in the 2nd and 3rd harmonics.
Lampe, H.M. & Baker, M.C. (1994). Behavioural response to song playback by male and female white-crowned sparrows of two subspecies. Bioacoustics 5(3): 171-185
Abstract
Nuttall's white-crowned sparrow Zonotrichia leucophrys nuttalli and the Puget Sound white-crowned sparrow Z. l. pugetensis intergrade through a zone of hybridization in southern California. The songs of the two differ in the sequence of syllable types and in the phonology of the complex syllables. We did a playback experiment to males of both subspecies in the field and to females of both subspecies in the laboratory to determine their response to the two subspecies songs. By making alterations of features of the songs, we also attempted to identify characteristics that account for subspecific recognition. Males of both subspecies were more responsive to their own subspecies song than to that of the other subspecies.
Substitution of Puget Sound complex syllables into the Nuttall's song caused a reduction in response by male Nuttall’s, but alteration of a Nuttall’s song to a Puget Sound sequence of syllables had no effect. Females of both subspecies gave more sexual displays when played a song of their own subspecies than when played that of the other subspecies. Female Nuttall's gave an intermediate response when played Nuttall's songs with Puget Sound complex syllables or when played Nuttall's songs altered to a Puget Sound sequence.
Puget Sound females did not discriminate between their own subspecies song and either of The altered stimulus songs separately. They did respond less to a song that combined both Alterations than to their own subspecies song.
Mbu Nyamsi, R.G., Aubin, T. & Brémond, J.C. (1994). On the extraction of some time dependent parameters of an acoustic signal by means of the analytic signal concept. Its application to animal sound study. Bioacoustics 5(3): 187-203
Abstract
When studying the acoustic signals of animals, it is often necessary to obtain the precise time structure of the frequency. It is also useful to extract the envelope of a signal or to modify a signal to obtain its frequency modulated part. This can be achieved digitally using the analytic signal concept. We deal here with the method. Definition and computation are described, its application is discussed and the performance: are compared to those of sonograph and zero-crossing methods. This paper presents a method enabling precise AM and FM analysis of different animal vocalisations. The method has also been used for the purpose of synthesis by extracting the frequency modulated part of a signal. It is found to be a powerful means of modifying some parameters of a natural signal without altering other features.
Waters, D.A. & Walsh, A.L. (1994). The influence of bat detector brand on the quantitative estimation of bat activity. Bioacoustics 5(3): 205-221
Abstract
Bat detectors are commonly used to monitor bat behaviour. Earlier research has suggested that there may be systematic differences in the response of different detectors to bat calls. Such differences would have important implications for the comparability of quantitative surveys conducted with bat detectors. The present study examines variability within and between brands of bat detector in accuracy of tuning, directionality and sensitivity to different types of bat echolocation call in bat detectors from three manufacturers. The consistency of results from a field survey incorporating the three brands in a standardised methodology are also examined. Significant differences were found within and between brands in directionality and sensitivity which would lead to bias in bat surveys. The implications of these findings for bat surveys are discussed, as are the design features of importance for species identification.
Hausberger, M., Richard, J.P., Black, J.M. & Quris, R. (1994). A quantitative analysis of individuality in barnacle goose loud calls. Bioacoustics 5(4): 247-260
Abstract
Barnacle goose loud calls were recorded in a semi-captive flock in Slimbridge. A quantitative analysis of those calls revealed a high degree of individuality in their structure. The duration and fundamental frequency of the calls did not vary much between birds, but the frequency of maximum amplitude did vary from one bird to another. No differences appeared between sexes. Individuality involved complex parameters that required special analysis programs. Frequency spectrum and frequency modulation (obtained by fundamental extraction) were individually distinctive. The combination of these two parameters gives excellent individual distinctiveness and enables 98% correct identification of the calls of individuals.
Henry, L., Hausberger, M. & Jenkins, P.F. (1994).The use of song repertoire changes with pairing status in male European starling. Bioacoustics 5(4): 261-266
Abstract
The experimental removal of the females from 5 breeding pairs of starlings caused the males to change both the quantity and quality of song when compared with 6 unmanipulated control pairs. The increase in the duration and commonness of warbling song after mate removal supports the idea that this type of song functions as mate attraction and stimulation. In contrast, the species-specific whistled songs are more important after pairing, which supports the idea that they are more involved in male-male interactions.
Thompson, N.S., LeDoux, K. & Moody, K. (1994). A system for describing bird song units. Bioacoustics 5(4): 267-279
Abstract
Bird song researchers have not agreed on a common set of units of analysis by which birds' songs of various different species might be described. Analysis of 50 papers reveals 28 unit designations and considerable variation in their application despite only three different methods for identifying units. The lack of consensus on units arises from the fact that units generated by the same methods at different levels of organization are given different names. A method for designating bird song units is offered for discussion which uses the concept of level of organization to stress the fundamental unanimity of method. It is hoped that consideration of this method will lead ultimately to greater standardization in the protocols by which researchers generate and name bird song units.
Evans, M.R. & Evans, J.A. (1994). A computer-based technique for the quantitative analysis of animal sounds. Bioacoustics 5(4): 281-290
Abstract
The method usually used to identify different sounds or divisions of sounds is to compare sonograms visually. There have been some attempts to reduce the subjectivity and increase the repeatability of this approach, for example by tracing the sonograms onto paper and examining the areas of overlap and mismatch, the use of multi-variate statistics and digitizing tablets. Digital recording of sounds has allowed sounds to be input directly into computers which can be used to display sounds and facilitate measurement. To date there has been little attempt at their use or analysis. We outline a series of programs which have been developed to compare statistically any unit of a sound with a pre-recorded library of similar units. The creation of such a library allows the rapid and objective categorization of large numbers of sounds. These programs have been used to analyse songs recorded from wrens Troglodytes troglodytes and house crickets Acheta domesticus. Potential applications of this software to the field of bioacoustic investigation are discussed.