Precision/Acoustic Variation: Vocal Production

描述（由申请人提供）：虎皮鹦鹉是一种小型鹦鹉，像鸣禽一样，有复杂的、经过学习的声乐曲目。Dooling实验室先前的研究结果表明，虎牙和人类一样，表现出伦巴第效应——随着环境噪音水平的增加，它们会改变发声的强度（Manabe et al., 1998）。我已经完成的试点工作将这些发现扩展到频率域，并表明虎牙可能只能改变几百赫兹或更少的音调。在这里，我建议使用操作性条件反射方法来探索虎牙发声的潜在机制。具体来说，我将研究在这些鸟类的接触呼叫中测量的声学变化的典型范围（特别是在频率，持续时间和振幅域），以及这些鸟类是否可以改变其呼叫的各种声学参数。我对确定接触呼叫产生的声学变化的极限特别感兴趣。这些研究的结果将极大地有助于我们理解该物种发声的机制，并通过与鸣禽和人类的比较，提供对发声行为的一般见解。

DESCRIPTION (provided by applicant): Budgerigars are small parrots that, like songbirds, have a complex, learned vocal repertoire. Previous findings in the Dooling lab have indicated that budgerigars, like humans, exhibit the Lombard effect - altering the intensity of their vocalizations in response to an increase in ambient noise level (Manabe et al., 1998). Pilot work that I have completed extends these findings in the frequency domain and suggests that budgerigars may only be able to alter the pitch of their vocalizations by a few hundred Hz or less. Here I propose to explore the potential mechanisms underlying vocal production in budgerigars using operant conditioning methods. Specifically, I will examine the typical range of acoustic variation (especially in the frequency, duration, and amplitude domains) measured in the contact calls of these birds and whether these birds can alter the various acoustic parameters of their calls. I am especially interested in determining the limits of acoustic change in contact call production. Results of these studies will contribute greatly to our understanding of the mechanisms underlying vocal production in this species and also offer insights into vocal behavior generally through comparisons with both songbirds and humans.