Dissertation Research: Biomechanics of Feeding in Loggerhead Shrikes

众所周知，幼鸟捕食成功的几率比成年鸟要低；这可能是他们经常在出生后第一年死亡的部分原因。然而，目前尚不清楚这种喂食的差异是由于所有幼鸟都通过学习随着时间的推移而提高了它们的喂食性能，还是成年鸟是更好的喂食者，因为所有身体或行为缺陷的幼鸟都在早期阶段死亡，只留下那些表现更好的幼鸟进入成年期。这项研究的目的是在联邦濒危的圣克莱门特红颅伯劳（Lanius ludovicianus mearnsi）中区分这些可能性，这是一种加利福尼亚圣克莱门特岛特有的掠食性鸣禽。它们的猎物捕获、处理和摄食行为随时间的变化将通过高速视频成像来测量。在其他鸟类中，摄食表现与生存和繁殖成功直接相关。这项研究将为圈养伯劳的管理人员提供帮助，以便重新建立野生种群，并提供客观标准，以决定哪些个体在释放后可能成功地养活自己，以及在哪个发展阶段。这项研究也将推进我们的理论理解，为什么摄食性能随着年龄的增长而提高，哪些身体和行为特征对成功捕获猎物很重要，以及作为一个群体，伯劳是如何进化出卓越的捕食能力的。最后，由于用于测量饲养性能的分析技术具有不同的生物医学应用（例如，运动机能学，运动生理学，物理疗法），该项目还将培训寻求医学，健康和野生动物专业职业的本科生。

It is well known that young birds succeed less often at catching food than do adults; this may be part of the reason that they frequently die during their first year of life. However, it is not clear whether this difference in feeding results from all young birds individually improving their feeding performance by learning over time, or whether adult birds are better feeders because all the physically or behaviorally deficient young birds die out at earlier stages, leaving only those that perform better to reach adulthood. The aim of this study is to distinguish among these possibilities in the federally endangered San Clemente Loggerhead Shrike (Lanius ludovicianus mearnsi), a predatory songbird endemic to San Clemente Island, California. The change over time of their prey capture, processing, and feeding performance will be measured using high-speed video imaging. Feeding performance has been directly linked to survival and reproductive success in other birds. This study will provide managers breeding shrikes in captivity in order to re-establish wild populations with objective criteria for deciding which individual shrikes are likely to feed themselves successfully if released, and at which stage of development. This study will also advance our theoretical understanding of why feeding performance improves with age, which physical and behavioral characteristics are important for successful prey capture, and how shrikes, as a group, have evolved their remarkable predatory capabilities. Finally, because the analytical techniques used for measuring feeding performance have distinct biomedical applications (e.g., kinesiology, exercise physiology, physical therapy), this project will also train undergraduate students who seek careers in medical, health, and wildlife professions.