Comparative Studies of Vocal Learning

9513821鸣禽的纳尔逊发声学习是一项复杂的运动技能，年轻的雄性会记住成年人的歌声，然后利用他们的记忆来控制自己的歌声输出。鸟类发声学习的一个结果是形成了发声方言，其中一个地方的雄性唱着与其他地方的雄性不同的相似的歌曲。直到最近，人们一直认为方言的形成涉及一个单一的过程：幼鸟模仿一个或多个成鸟在幼鸟定居的时间和地点繁殖。最近的证据表明，对在不同时间和地点全部或部分获得的大型曲目中的歌曲进行选择性磨损的独立过程也可以导致邻居之间的歌曲共享。这项拟议的研究将考察歌曲过度生产和选择性磨损在当地歌曲方言形成中的作用。该协会将采取比较的方法，研究白冠麻雀(Zonotricia Leucophrys)的不同亚种。将进行实地观察、实验室和田间实验，以比较形成当地方言的一个亚种(Z.L.oriantha或Z.L.leucoprys)和另一个不形成当地方言的亚种(Z.L.Gambeli)的发声发育过程。在野外，PI将观察雄性在确定领地时的声音互动，并在春季初确定它们歌曲制作曲目的大小，并比较它们是有选择地保留还是拒绝与邻居匹配的歌曲。这将检验这样一种假设，即在进化多样化期间，发育途径是保守的，而且变化通常发生在终末阶段。然后，PI将进行野外和实验室回放测试，对比两个亚种雄性的歌曲匹配行为。这些实验旨在揭示歌曲知觉分类的差异，并确定歌曲识别中可能存在的基于遗传的差异。PI还将采用一种新的方法来测量歌曲学习，该方法独立于模仿的产生，以检查歌曲在敏感阶段和随后的存储间隔期间是如何记忆的。最后，PI将进行一项歌曲学习实验，以评估与磁带辅导相比，现场辅导教师是否修改或延长了歌曲习得的早期敏感阶段。

9513821 Nelson Vocal learning in song birds is a complex motor skill in which young males memorize the songs of adults, and then use their memory to control their own song output. One consequence of vocal learning in birds is the formation of vocal dialects in which males at one locality sing similar songs that differ from those of males at other localities. Until recently, it has been assumed that a single process is involved in the formation of dialects: the young bird imitates one or more adults at the time and place the youngster settles upon a breeding territory. Recent evidence suggests that an independent process of selective attrition of songs from a large repertoire acquired in whole or in part at a different time and place can also lead to song sharing between neighbors. The proposed research will examine the role of song overproduction and selective attrition in the formation of local song dialects. The PI will take a comparative approach by studying different subspecies of the white-crowned sparrow (Zonotrichia leucophrys). Field observations, and laboratory and field experiments will be conducted to compare processess of vocal development in one subspecies that does form local dialects (Z. l. oriantha or Z. l. leucophrys) with another that does not (Z. l. gambelii). In the field, the PI will observe vocal interactions between males as they settle upon territories, and determine the sizes of their song production repertoire early in Spring, and compare whether they selectively retain or reject songs that match their neighbors. This will test the hypothesis that developmental pathways are conserved during evolutionary diversification, and that changes often are made to terminal stages. The PI will then conduct field and laboratory playback tests contrasting the song matching behavior of males of two subspecies. These experiments are designed to reveal differences in the perceptural categorization of songs, and to identify possible genetically-based differences in song pe rception. The PI will also employ a new method for measuring song learning that is independent of the production of imitations to examine how songs are memorized during the sensitive phase and during the subsequent storage interval. Finally, the PI will conduct a song learning experiment to assess whether live tutors modiy or extend the early sensitive phase for song acquisition, as compared with tape tutoring.