Dissertation Research: Vocal Behavior at Subspecies and Dialect Boundaries in the Bronzed Cowbird

最近三年对青铜色牛鹂（Molothrusaeneus）的研究揭示了一种在许多重要方面不同于其他鸟类的社会系统。这个项目将试图确定这些差异对它们的进化有什么影响。将记录雄性青铜牛鹂的鸣声，并在不同种群中进行比较。歌声也会回放给雄牛鹂听，以确定歌声的变化对它们的意义。作为幼虫寄生虫，牛郎鸟拥有一种不同寻常的繁殖方式；雌性牛鹂在其他鸟类的巢中产卵，然后这些鸟类把它的后代当作自己的后代来抚养。雏鸟寄生对其寄主物种的影响已被广泛报道和争论。但这对牛郎鸟自身的进化有什么影响呢？一个后果是，雄性牛郎鸟在离开养父母加入自己的物种之前，没有机会学习它们的歌声。因此，他们学习的机会在某种程度上受到限制，这与其他物种不同。歌曲学习在物种形成等进化过程中扮演什么角色？为了解决这个问题，这项研究提出了一个问题，即一群被分开的牛郎鸟是否有可能分裂成不同的物种。人们希望收集到的关于这种很少被研究的牛郎鸟的信息将有助于人们对其行为、栖息地的利用以及对其他物种的潜在影响有一个大致的了解。

Non Technical Abstract Proposal #: 98001041 PI: M. Ryan / P. Warren The last three years of research on the bronzed cowbird (Molothrusaeneus)have uncovered a social system that differs in many important ways from other birds. This project will attempt to determine what effects these differences have on their evolution. Songs of male bronzed cowbirds will be recorded and compared among different populations. Songs will also be played back to male cowbirds to determine what variation in song means to the birds. As brood parasites, cowbirds possess an unusual form of reproduction; the female cowbird lays her eggs in the nests of other bird species who then raise her offspring as if it were their own. The effects of brood parasitism on the cowbirds' host species have been much publicized and much debated. But what are the evolutionary consequences for the cowbirds themselves? One consequence is that male cowbirds do not have the opportunity to learn their songs until they leave their foster parents and join their own species. Thus, their opportunities for learning are constrained in a way unlike that in other species. What role does song learning play in evolutionary processes like speciation? To address this problem, this study asks whether groups of cowbirds which have been separate from one other are likely to split into different species. It is hoped that information gathered on this little-studied species of cowbird will contribute to a general understanding of its behavior, its use of habitat, and therefore its potential to impacts on other species.