ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753085

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In this paper we document the pattern of geographic variation in song of the Corn Bunting in a marked population in Sussex. Song variation is best described as a system of local dialects with three song types in each dialect. We examine the inheritance of dialects from father to son; sons sing the same dialect as their nearest neighbour, rather than inheriting the dialect of the father. Therefore songs seem to be learned after dispersal. We also compare the dialects of mates and fathers of females: our results suggest that females do not rely on dialects when pairing. These results are discussed in the context of the current controversy surrounding other species with dialects and hypotheses relating dialects to the genetic structure of populations.

ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753086

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Sounds produced by Finback WhalesBalaenoptera physaluswere recorded from a stationary hydrophone in the St. Lawrence Estuary from June to September. The vocalizations consisted of frequencies below 120 Hz; impulsive sounds had frequencies up to 1 kHz. Over 80% of the sounds were downsweeping calls. Frequency variations in the downsweeps were correlated with social context. Constant calls, upsweeps, wavers and a frequency and amplitude modulated call were rare and may be context specific. Vocalization rates varied with the number of animals present and context, but could not be used as a census technique. Comparisons are made with the data from other investigators in both the Northwest Atlantic and the Northeast Pacific. Frequency and time characteristics for Finback downsweeps are summarized and discussed as components important for species recognition.

ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753087

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Measures of six temporal relations in the pigeon's courtship songs from four individual males which differed in age and courtship experience were taken. Intra- and interindividual variation was studied. Individual long term vocal stability is especially found in the whole length of the strophe, the length of the “trill” phrase and the length of the “coo”.

ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753088

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Knowledge of the vocalizations of Afrotropical birds is very limited and many problems exist. Seasonality of vocal activity has not been properly researched in the context of potential variability in the times of breeding. The different types of duetting and chorus singing, as exemplified by the African barbets, Capitonidae, need to be studied to correct the over-generalized treatment of this subject. Fuller information is required about geographic variation of those vocalizations which there is a tendency to use as criteria for taxonomic separation of species. Other problems which invite more research are mimicry, nocturnal and diurnal song, the extent of species' repertoires of calls, and vocalizations during breeding activities. There is an urgent need for more studies to be made of the vocal behaviour of birds in Africa where threats to the habitats are increasing so rapidly.

ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753089

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Sound production in seven species of bush crickets (Tettigonia cantans, T. virridissima, Decticus verrucivorus, D. albifrons, Psorodonotus illyricus, Ephippiger ephippiger, E. discoidalis)has been investigated. Aspects of wing morphology have been compared and show that areas of the dorsal fields and the mirror are correlated with the dominant frequencies of the songs. Tooth removal from the pars stridens produces gaps in the time structure of single syllables but no change in the song power spectra. The removal of the tegminal lateral field in long- and medium-sized wing species (T.c., T.v., D.a., D.v.)produces an increase in the ultrasonic components of caudally-emitted sound. This suggests an absorbing function for the lateral fields in intact animals. In all species removal of a small portion of the mirror frame or of the mirror membrane attenuates the whole stridulatory signal, but especially the ultrasonic components. The mirror therefore functions as an amplifier, especially for high frequencies. Manipulation of the dorsal fields of long- and medium-winged species, or the distal edges of tegmina of brachypterous species, deletes or shifts the songs' dominant frequency. Thus the different tegminal structures (and especially the dorsal fields) contribute to the time structures and power spectra of the stridulatory songs of these species.

ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753090

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Many animal vocalizations are non-periodic, frequency-modulated signals. Because this type of signal varies simultaneously in two dimensions, time and frequency, spectrographic measurement is constrained by the “uncertainty principle”: to increase accuracy of measurement in one dimension we must sacrifice accuracy of measurement in the other dimension. Although this trade-off is unavoidable, inherent in the measurement of frequency, for any particular frequency-modulated, non-periodic signal, there is an intermediate, optimal setting of spectrographic bandwidth, equal to the square root of the average rate of change of the measured signal. This optimal bandwidth minimizes the time-frequency smear, and thus permits the most accurate measurement of the instantaneous frequency. Investigators analyzing the microstructure of animal vocal signals therefore should choose their analyzer bandwidths to match the signals under study.

ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753091

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753092

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753093

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1988.9753094

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor