AUDITORY EXPERIENCE AND SONG DEVELOPMENT IN THE CHAFFINCH FRINGILLA COELEBS

The present paper describes the results of experiments designed to evaluate the importance of auditory-motor experience in the development of song in the Chaffinch. For this purpose a number of Chaffinches collected as nestlings or adults were deafened by extirpating the cochlea at different ages. Recordings of their song made subsequently provide the material on which the paper is based. Since the results of the experiments can only be interpreted in the light of knowledge of normal song development, the latter is described from the observation of previous workers and from some new material. Of the 20 males deafened, only three came into full song of their own accord; song was induced in the rest by the administration of testosterone phenylacetate or testosterone propionate. Songs of abnormal length were common among first-year males though males deafened when two or more years old produced song of the normal length. The song of male Chaffinches deafened as adults, that is after they had produced full song for one or more breeding seasons, was infistinguishable from that produced by intact adult males. They even went through a “plastic” song stage in which some “intermediate” themes occurred. A first-year male deafened when it had almost stabilized its song produced song that gradually deviated more and more from normal song. This indicates that the bird had not yet laid down a long-term memory of its song independent of auditory feedback. First-year male Chaffinches deafened during early spring, mid-winter and late sumer, respectively, show that the more they were deprived of the normal period of auditory-motor experience, the simpler was the song they produced in their first spring. Thus, at the time of deafening they had acquired a particular auditory-motor experience, and it is the type of element established up to that time that is incorporated into full song. Male chaffinches brought into the laboratory as nestlings and deafened when three months old produced a virtually sfyctureless song, in which the only recognizable element was a sound reminiscent of the juvenile “chirrup”. The subsong and other calls of these birds were also highly abnormal. Song development in the Chaffinch clearly starts before song as such has made its appearance. The available evidence suggests that the kind of song a male Chaffinch produces depends directly on its auditory-motor experience before deafening. There is no indication that deafening achieves its effects on the resultant song by interfering with the hormonal substrate. Relatively stable song end patterns develop in the absence of auditory feedback, so their occurrence does not necessitate the postulation of templates or preconceived patterns. Song development differs markedly from species to species.     

MICRODIALECT AND GROUP SIGNATURE IN THE SONG OF THE SKYLARK ALAUDA ARVENSIS

ABSTRACT

The Skylark Alauda arvensis is a territorial species of open landscape in which pairs settle in stable and adjacent territories during the breeding season. Due to the heterogeneity of the habitat, territories are gathered in patches spaced by a few kilometres, in which each male produces very long and complex flight songs as a part of the territorial behaviour. We showed that, in a given patch, all the males (neighbours) share some particular sequences of syllables in their songs, whereas males settled in different patches (strangers) have almost no sequences in common. Such a phenomenon is known as microdialect. To test the hypothesis that these shared sequences support a group signature, we made playback experiments with “chimeric” signals: songs of strangers where the sequences shared by neighbours were artificially inserted. Behavioural responses to playbacks indicated a neighbour-stranger discrimination consistent with the dear enemy phenomenon, i.e. a reduced aggression toward neighbours compared to strangers. Furthermore, the same level of responses, observed when a “chimeric” song and a neighbour song were broadcast, indicated that shared sequences are recognised and identified as markers of the neighbourhood identity.     

THE SINGER AND THE SONG: ON THE RECEIVING END OF BIRD SONG

Variation in singing behaviour between males can involve fixed differences such as the song type composition of repertoires, as well as more flexible effects such as matched counter-singing (Krebs & Kroodsma, 1980; Section III. 4), differences in bout length (the number of songs in a period of song) and changes in strophe length. Short-term strophe length changes seem to be related to the willingness and ability of males to respond strongly to playback. Whether this is because strophe length indicates motivation or the degree of exhaustion of the neuromuscular song-production system, or both, is currently unclear.     

NATURAL SELECTION ON BEAK AND BODY SIZE IN THE SONG SPARROW

We documented temporal patterns of natural selection on beak and body traits in a song sparrow population. We looked for evidence of selection in association with reproduction and overwinter survival in order to identify the conditions under which size in beak and body traits is adaptive. We also attempted to identify the specific traits most closely associated with fitness under these conditions. Selection was observed in association with both survival and reproduction. Patterns of selection differed between the sexes. Selection on males was weak and stabilizing in association with overwinter survival. Selection on females was strong, was both stabilizing and directional, and was associated with both survival and reproduction. In females, traits that enhanced juvenile survival also reduced reproductive success; i.e., there was a trade-off between survival and reproduction. Patterns of selection in the song sparrow parallel those reported for the Galápagos finch, Geospiza fortis. However, in song sparrows, selection occurred mainly on tarsus length and beak length, and not on beak depth or width as in G. fortis. This difference may occur because most North American sparrows partition food resources by habitat, while most Galápagos ground finches partition food by seed size.     

DIALECTS AND GEOGRAPHICAL VARIATION IN THE SONG OF THE SPLENDID SUNBIRD NECTARINIA COCCINIGASTER

The male Splendid Sunbird has only one song type, each note of which has a simple frequency/time profile. An analysis of the songs of males from several localities near Legon (5^.63° N, 0.19° N) showed that there are clear-cut song dialects characterizing each population. Those parts of the song giving rise to dialects are the time interval between consecutive pairs of notes (the time interval pattern) and the frequency/time profile of each note.
The dialects were preserved over a period of three years (the duration of the study) and there was little variation in the song of a ringed bird over a period of two months. The boundary between dialects is apparently quite sharp, occurring perhaps within a distance of 50 m.
Marked geographical variation in the song occurs, and is expected because of the mosaic of dialects that presumably exist throughout the sunbird's range in southern Ghana. For dialects to be effective in keeping populations together, those characteristics of the song which give rise to dialects should be readily and quickly discerned and need not require a statistical demonstration. This condition holds for the song of the Splendid Sunbird.
The results are compared with the ideas of Nottebohm (1964) and Thielcke (1969) on the maintenance and usefulness of song dialects.     

ENVIRONMENTAL AND GENETIC CONTROL OF BRAIN AND SONG STRUCTURE IN THE ZEBRA FINCH

Birdsong is a classic example of a learned trait with cultural inheritance, with selection acting on trait expression. To understand how song responds to selection, it is vital to determine the extent to which variation in song learning and neuroanatomy is attributable to genetic variation, environmental conditions, or their interactions. Using a partial cross fostering design with an experimental stressor, we quantified the heritability of song structure and key brain nuclei in the song control system of the zebra finch and the genotype‐by‐environment (G × E) interactions. Neuroanatomy and song structure both showed low levels of heritability and are unlikely to be under selection as indicators of genetic quality. HVC, in particular, was almost entirely under environmental control. G × E interaction was important for brain development and may provide a mechanism by which additive genetic variation is maintained, which in turn may promote sexual selection through female choice. Our study suggests that selection may act on the genes determining vocal learning, rather than directly on the underlying neuroanatomy, and emphasizes the fundamental importance of environmental conditions for vocal learning and neural development in songbirds.     

松嫩平原南部植被与环境相关性的探讨

从环境格局入手,分析植被对环境的反应,是研究植被与环境相关性的一条途径。本文采用该途径。从生态种组入手,分析松嫩平原南部植被与环境的相关性,根据该区自然条件的特点,用生态系列表,分析植物对土壤盐碱,水分,有机质和氮素的含量以及土壤酸度的反应。依植物对上述各因素要求的相似性划分单因子生态种组,并以此为基础,综合植物对上述各因素反应的相似性,划分了11个综合因子生态种组,阐明 生态种组与植物群落及立地的关系。依据三者的关系,结合牧业生产,划分了4个立地类型。     

CORRELATED EVOLUTION OF BEAK MORPHOLOGY AND SONG IN THE NEOTROPICAL WOODCREEPER RADIATION

Mating signals may diversify as a byproduct of morphological adaptation to different foraging niches, potentially driving speciation. Although many studies have focused on the direct influence of ecological and sexual selection on signal divergence, the role of indirect mechanisms remains poorly understood. Using phenotypic and molecular datasets, we explored the interplay between morphological and vocal evolution in an avian radiation characterized by dramatic beak variation, the Neotropical woodcreepers (Dendrocolaptinae). We found evidence of a trade-off between the rate of repetition of song syllables and frequency bandwidth: slow paced songs had either narrow or wide frequency bandwidths, and bandwidth decreased as song pace increased. This bounded phenotypic space for song structure supports the hypothesis that passerine birds face a motor constraint during song production. Diversification of acoustic characters within this bounded space was correlated with diversification of beak morphology. In particular, species with larger beaks produced slower songs with narrower frequency bandwidths, suggesting that ecological selection on beak morphology influences the diversification of woodcreeper songs. Because songs in turn mediate mate choice and species recognition in birds, these results indicate a broader role for ecology in avian diversification.     

RECLAIMING THE PATIENT'S VOICE AND SPIRIT IN DYING: AN INSIGHT FROM ISRAEL

In the latter half of the 20th century, Western medicine moved death from the home to the hospital. As a result, the process of dying seems to have lost its spiritual dimension, and become a matter of prolonging material life by means of medical technology. The novel quandaries that arose led in turn to medico‐legal regulation. This paper describes the recent regulation of dying in Israel under its Dying Patient Law, 2005. The Law recognizes advance directives in principle, but limits their effect and form through complex medico‐legal artifices. It reflects a culture that places high value on both scientific medicine and the sanctity of life as such, and illustrates a medical culture that pitches battle against death. At the same time, the Law constructs the will of the individual in a medico‐legal language that is alien to the lay person. The paper suggests an alternative approach to advance care planning that is patient‐centred and addresses the psycho‐social needs of the individual in terms of her relational autonomy. From this perspective, advance care planning becomes an opportunity to extract the patient from the medical context and allow her to speak about her approaching death with close ones in her own terms of reference. To this end, there is a need for facilitation of an intimate encounter where patients can speak about their concerns with their loved ones. The paper also presents a methodological approach of attentive listening, which can be applied across diverse cultures and circumstances.     

CULTURAL INHERITANCE OF SONG AND ITS ROLE IN THE EVOLUTION OF DARWIN'S FINCHES

Songs of Darwin's finches were studied on the Galápagos Island of Daphne Major from 1976 to 1995. A single, structurally simple, and unvarying song is sung throughout life by each male of the two common species, Geospiza fortis (medium ground finch) and G. scandens (cactus finch). Songs of the two species differ strongly in quantitative features, and individual variation among males is much broader in G. fortis than in G. scandens. Although there are exceptions, songs of sons strongly resemble the songs of their fathers. They also resemble the songs of their paternal grandfathers, but not their maternal grandfathers, indicating that they are culturally inherited and not genetically inherited. Female G. fortis display a tendency to avoid mating with males that sing the same type of song as their father. They also avoid mating with males that sing heterospecific song, with very rare exceptions. Thus song, an evolving, culturally inherited trait, is an important factor in species recognition and mate choice. It constrains the mating of females to conspecifics, even when there is no genetic penalty to interbreeding, and thus may play a crucial role in species formation by promoting genetic isolation on secondary contact. The barrier is leaky in that occasional errors in song transmission result in misimprinting, which leads to a low incidence of hybridization and introgression. Introgression slows the rate of postzygotic isolation, but can produce individuals in novel genetic and morphological space that can provide the starting point of a new evolutionary trajectory.     

SONG POPULATIONS AND DISPERSAL IN STEELBLUE AND PURPLE WIDOWFINCHES

Payne, R. B. 1985. Song populations and dispersal in Steelblue and Purple Widowfinches. Ostrich 56:135-146.

Songs of Steelblue Widowfinches Vidua chalybeata were recorded over eight years at Lochinvar National Park, Zambia. Neighbouring males share their song-type repertoires. Individual birds changed the structural details of all song types in their repertoire from year to year, and over 4–5 years the songs accumulated changes so that a song type could scarcely be recognized as the same. A few males in addition switched their song repertoires when they dispersed from one song population to another, or when their old neighbours disappeared and new neighbouring males sang a different song repertoire. Individual marked adult birds moved from one song neighbourhood to another. Purple Widowfinches had a similar song behaviour but only one song dialect was found in the study area.

An estimate of the proportion of immigrants was made from the proportion of birds with songs unlike their neighbours, and from birds that had a mixed song repertoire or that switched their song repertoires. Song populations were sampled at several localities in the Transvaal, Botswana, Zambia, Kenya, Tanzania, Cameroon, and Nigeria. An overall minimal estimate of dispersal between song neighbourhoods was 18 %. The incidence of observed dispersal and the movements indicated by the song differences among local widowfinches were considerable and more than sufficient to prevent genetic isoloation and differentiation of local song populations.     

白头鹎方言的初步研究

对浙江省乘泗岛，普陀岛，温岭，长兴，杭州和龙游等６个地区白头鹎的鸣声进行了研究，发现它们鸣声主句的语调，音节数，持续时间，频谱特征和频率范围等均有差异，说明白头鹎鸣声中普遍存在“方言”，但它们作为同一个种在鸣声主句上有其共同特征：主要是鸣声多在１．５－３ｋＨｚ的低中频段内变化，单音节的鸣叫声等都极为相似。