Dissertation Research: Modeling Winter Food Limitation in a Migratory Bird

候鸟的数量受到多种环境和生态因素的限制。在越冬地、繁殖地和迁徙期间发生的事件都可能影响它们的种群数量。目前，人们对控制候鸟数量的生态机制知之甚少。基于证据的生态相关性表明，食物丰富可能是冬季限制候鸟数量的最重要因素；然而，对于温带或热带越冬地区的候鸟，没有公开发表的实验证据支持这一假说。利用在牙买加越冬的燕鸟(Seiurus Aurocapillas)，我们正在研究对食物供应的实验操作如何影响迁徙鸣鸟的行为、生理、生存和迁徙离开时间。基于这些实验和观测研究得出的估计，我们将构建一个模拟模型，以调查人口如何对气候变化做出反应，气候变化通过变化的降雨模式影响食物丰度。模型预测将通过将长期的大陆规模的燕鸟种群变化与整个燕窝鸟冬季分布的气候和植被模式的历史记录相关联来检验，这些变化是通过繁殖鸟类调查数据测量的。我们采取了一种独特的方法，使用模拟建模来将限制候鸟数量的机制的小规模、基于野外的实验测试与广泛分布的北美候鸟物种的种群规模的大规模变化联系起来。

Populations of migratory songbirds are limited by multiple environmental and ecological factors. Events occurring on the wintering grounds, the breeding grounds, and during migration all potentially affect their population size. Currently, the ecological mechanisms that control populations of migratory birds are poorly understood. Evidence based ecological correlations suggests that food abundance may be the most important winter-season factor limiting populations of migratory songbirds; however, no published experimental evidence exists to support this hypothesis for migrants in temperate or tropical wintering areas. Using the Ovenbird (Seiurus aurocapillus) wintering in Jamaica, we are investigating how experimental manipulations of food availability affect the behavior, physiology, survival, and migration departure timing of a migratory songbird. Based on estimates derived from these experimental and observational studies, we will construct a simulation model to investigate how populations may respond to climate change, which affects food abundance via patterns of changing rainfall. Model predictions will be tested by correlating long-term, continental-scale changes in Ovenbird populations, as measured by Breeding Bird Survey data, with historical records of climate and vegetation patterns from across the Ovenbird's winter distribution. We take a unique approach by using simulation modeling to link small-scale, field-based experimental tests of the mechanisms that limit migratory bird populations with well documented large-scale changes in population size of a widely distributed North American migratory bird species.