LTREB: Demography and Disease Ecology of a Colonial Bird

这项提议是为了继续对内布拉斯加州西南部悬崖燕子的人口和社会行为进行长达25年的研究。我们将监测有标记的鸟类样本的生存、扩散和群体选择，这些鸟类现在有158,373只。这些信息将应用于正在进行的燕子种群生物学调查，包括研究群体规模的影响，也将用于研究1996年和2004年在研究区域发生的两次罕见气候事件的长期后果。在过去的130年里，内布拉斯加州西南部只发生过两次这样的恶劣天气。收集到的数据将应用于以下工作：(1)与崖燕及其体外寄生虫相关的病毒的生态学和进化，我们正在研究这种脑炎相关病毒在研究区域内通过鸟类在蜂群之间传播的频率，特定年份的蜂群使用与病毒流行的关系，鸟类运动是否与研究区域内病毒亚型的进化差异模式有关；以及病毒如何影响带标记的崖燕在数年内和数年间的生存，以及它在多大程度上代表了群体生活的劣势；(2)形态进化和自然选择对繁殖时间的影响，研究罕见的气候事件导致的体型和翅尾两侧不对称程度的进化变化，以及2004年繁殖季节普遍的筑巢失败是否会对繁殖时间产生选择作用，导致种群在连续几代中更早产卵。

This proposal is to continue a 25-year long study of demography and social behavior of cliff swallows in southwestern Nebraska. We will monitor survival, dispersal, and colony choice for a sample of marked birds that now numbers 158,373 individuals. This information will be applied to ongoing investigations of swallow population biology that incorporate study of the effect of group size, and will also be used to study the long-term consequences of two rare climatic events that occurred in the study area in 1996 and 2004. Severe weather of the timing and magnitude of these events has occurred in southwestern Nebraska only twice in the last 130 years. Data gathered will be applied to work on (1) the ecology and evolution of a virus associated with cliff swallows and their ectoparasites, in which we are studying how often this encephalitis-related virus is transmitted between colonies within the study area by birds, how colony use in a given year is related to prevalence of virus, whether bird movement is related to patterns of evolutionary divergence of virus subtypes within the study area, and how the virus affects survival of marked cliff swallows within and between years and thus to what degree it represents a disadvantage of living in colonies; and (2) morphological evolution and natural selection on breeding time, in which we are studying evolutionary changes in body size and extent of bilateral asymmetry in wings and tail brought about by the rare climatic events, and whether the widespread nesting failures in the 2004 breeding season will exert selection on breeding time and lead to earlier egg-laying in the population in successive generations.