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21.
Zusammenfassung Bergmann et al. (1988) haben die vorsichtige Hypothese aufgestellt, daß für die räumliche Verteilung der unterschiedlichen Dialekte des Regenrufes (Brutzeitrufes) des Buchfinken (Fringilla coelebs) die akustische Umwelt mit verantwortlich sein könnte. Konkret wurde vermutet, daß der huit-Ruf bevorzugt in städtischen Gebieten mit hoher Verkehrslärmbelastung benutzt wird, da dieser reintonige Dialekttyp Lärmbereiche besonders gut durchdringen würde. Zur Prüfung dieser Hypothese wurde in den kreisfreien Städten Remscheid, Solingen und Wuppertal eine Untersuchung durchgeführt. Analysen des Verkehrslärms ergaben, daß mit zunehmender Frequenz der Schalldruck abnimmt und zwischen 4,0 und 5,0 kHz auf einen unbedeutenden Wert abfällt. Für die Durchdringung von Verkehrslärm durch Regenrufe werden unter Berücksichtigung der Hörfähigkeit eines Buchfinken 4,5 bis 7,0 kHz als optimal angesehen. Da die Hauptfrequenz des huit-Rufes nicht 4,2 kHz überschreitet, ist eine Adaptation an den Verkehrslärm unwahrscheinlich. Außerdem wurden die Regenrufe unterschiedlicher Dialekte den einzelnen Lärmbelastungszonen zugeordnet. Es konnte keine Abhängigkeit der Dialekttypen von der Lärmbelastung festgestellt werden. Insgesamt konnte die vorsichtige Hypothese von Bergmann et al. (1988) nicht bestätigt werden.
Possible Rain call selection in the Chaffinch(Fringilla coelebs) by noise intensity — an investigation of a hypothesis
Summary Bergmann et al. (1988) formed the tentative hypothesis that the spatial distribution of different rain call dialects in the Chaffinch (Fringilla coelebs) could be caused by the acoustic environment. In concrete terms, it was supposed that the huit call was used predominantly in urban districts with a high level of traffic noise because this type of sound is more capable of penetrating the traffic noise. In order to test this hypothesis, a study was conducted in the towns Remscheid, Solingen and Wuppertal. Analysis of traffic noise showed that the sound pressure decreases with ascending frequency and reaches an insignificant value between 4,0 and 5,0 kHz. In view of the hearing capability of the Chaffinch it seemed that rain calls with frequencies of 4,5 to 7,0 kHz are best for piercing traffic noise. However, the main frequencies of the huit call do not exceed 4,2 kHz, which means that an adaptation to traffic noise is improbable. In addition to this the rain calls of different dialects were classified into noise zones. No dependence of dialect on traffic noise intensity could be established. Summing up, the cautious hypothesis of Bergmann et al. (1988) could not be corroborated.
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22.
In songbirds, territorial songs are key regulators of sexual selection and are learned from conspecifics. The cultural transmission of songs leads to divergence in song characteristics within populations, which can ultimately lead to speciation. Many songbirds also migrate, and individual differences in migratory behaviours can influence population genetic structure and local song differentiation. Blackcaps, Sylvia atricapilla, exhibit versatile territorial songs and show diversity in migration behaviours. They therefore comprise a good model for investigating the relationships between migratory patterns, song variation, and genetic diversity. We studied a migratory population (two groups near Paris) and a sedentary population (three groups in Corsica). All of the birds were ringed and blood sampled to investigate genetic relatedness using 17 microsatellite loci. A detailed song analysis showed that this species has a complex repertoire (> 100 syllables), which required the development of a semi‐supervised method to classify different categories of syllables and compare sequences of syllables. Our analysis showed no genetic structuring among populations: individuals belonging to the same group were not genetically closer than those from different groups. However, we found a strong wingsize difference between sedentary and migratory populations. We also showed that geographical variations in songs rely at least on both syllable and sequence content. Unexpectedly, despite a higher turnover of individuals, migratory groups share as many syllables and sequences as sedentary groups, which raises interesting issues on song learning and the maintenance of dialects in migratory birds.  相似文献   
23.
In common with human speech, song is culturally inherited in oscine passerine birds (‘songbirds’). Intraspecific divergence in birdsong, such as development of local dialects, might be an important early step in the speciation process. It is therefore vital to understand how songs diverge, especially in founding populations. The northward expansion of the Light‐vented Bulbul Pycnonotus sinensis (J. F. Gmelin, 1789) into north China in the last 30 years provides an excellent opportunity to study birdsong evolution. We compared ~4400 songs from newly established northern populations with ~2900 songs from southern populations to evaluate song divergence after recent expansion. The total pool of syllables and especially song types was considerably smaller in the north than in the south, indicating ‘founder effects’ in the new population. The ancestral pattern of mosaic song dialects changed into a pattern of wide geographical sharing of a few song types and syllables, likely the result of fewer geographical barriers to ‘meme flow’, and the recent spread across a large area in the north. Our results suggest that song evolution and vocal trait shifts can arise rapidly after range expansion, and that in the Light‐vented Bulbul ‘founder effects’, geographical isolation, and recent rapid expansions played important roles in the evolution of song dialects.  相似文献   
24.
Bird song often varies geographically, and when this geographicvariation has distinct boundaries, the shared song types arereferred to as song dialects. We investigated the role of songdialect in male mating success in a wild breeding populationof mountain white-crowned sparrows (Zonotrichia leucophrysoriantha). In 2 of 3 years, males singing unusual songs ("nonlocal"males) had lower total fertilization success (measured by microsatellitepaternity analysis) than did males singing the local dialect ("local" males). Similarly, females produced disproportionately more young with local than with nonlocal males. However, dialectwas not a significant predictor of male mating success whencontrolling for other factors that might affect paternity.Instead, the low mating success of nonlocal males was apparentlydue to an interaction between song dialect and parasite load.Nonlocal males were more severely infected by bloodborne Haemoproteusthan were local males, although they did not differ in anyother measured aspect of quality. Immigrant birds may be immunologically disadvantaged, possibly due to a lack of previous experiencewith the local parasite fauna, resulting in low mating success.  相似文献   
25.
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