Dissertation Research: Selective Attrition During Song Development

9701351比彻鸟的歌声被广泛认为是研究学习的生物学基础的模型系统。它提供了迄今为止脊椎动物自然学习的最佳例子，与人类语言学习有许多惊人的相似之处。此外，近年来关于歌曲学习的大脑机制的许多发现表明，这个模型系统可能揭示了大脑中学习的一般过程。这一提议将研究歌曲学习的一个关键方面，即幼鸟记忆更多歌曲的倾向，而不是它们最终保留的歌曲曲目。大多数研究都是在实验室进行的，但主要的研究将在自由生活的鸣禽种群中进行，从而可以评估鸣禽学习的适应性意义和生态背景。主要的问题是，为什么雄性鸣禽在幼年鸣叫时比成年鸣叫时产生更多的鸣叫类型？具体来说，为什么他们保留某些歌曲而不是其他歌曲。假设是，它们在第一个繁殖季节保留那些与邻居最匹配的歌曲。该研究将记录雄性幼鸟的“塑料”鸣声（鸣声直到鸟的第一个春天的三、四月才完全形成），并将这些鸣声与鸟类成年曲目中的“结晶”鸣声类型以及鸟类出生夏季和第一个春天（部分重叠组）的成年雄性鸣声进行比较。在实验室进行的一项平行研究也将由几只成年雄性指导人工饲养的鸟类进行。这项研究将使人们更好地理解歌曲是如何学习的，并对学习过程有更深入的了解。

9701351 Beecher Bird song is widely recognized as a model system for investigations into the biological basis of learning. It provides the best example to date of natural learning in a vertebrate, with many striking parallels to human language learning. Moreover, in recent years many discoveries concerning the brain mechanisms underlying song learning have suggested that this model system may reveal much about the general processes of learning in the brain. This proposal will examine one key aspect of song learning, the tendency of young birds to memorize more songs than they will ultimately keep for their final repertoire of songs. Most studies have been done in the laboratory, but the major study will be conducted on a free-living population of song sparrows, thus permitting evaluation of the adaptive significance and ecological context of song learning. The major question addressed is why do male song sparrows produce more song types during juvenile song than they have in their final adult repertoires? Specifically, why do they keep certain songs and not others. The hypothesis is that they keep those songs that best match those of their neighbors during their first breeding season. The research will record "plastic" songs of juvenile males (song is not fully formed until March or April of the bird's first spring) and compare these to "crystallized" song types in the bird's adult repertoire and to the songs of adult males present in the bird's natal summer and his first spring (a partially overlapping group). A parallel study in the laboratory of hand-raised birds tutored by several adult males will also be conducted. This research will allow a better understanding of how song is learned, and insights into learning processes in general.