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学和社会行为进行长达25年的研究。我们将监测标记鸟类样本的生存、分散和群体选择，这些样本现在有158,373只个体。这些信息将用于正在进行的燕子种群生物学调查，其中包括对种群规模影响的研究，还将用于研究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，这些事件发生的时间和规模的恶劣天气只在内布拉斯加州西南部发生过两次。收集到的数据将被用来研究(1)与悬崖燕子及其体外寄生虫相关的病毒的生态和进化，其中我们正在研究这种脑炎相关病毒在研究区域内的群体之间传播的频率、给定年份的群体使用与病毒流行的关系、鸟类活动是否与研究区域内病毒亚型的进化分化模式有关、以及病毒如何影响有标记的悬崖燕子在年内和年间的存活，从而在多大程度上代表在群体中生活的不利条件；(2)繁殖期的形态进化和自然选择，研究罕见气候事件带来的个体大小和翅膀、尾部两侧不对称程度的进化变化，以及2004年繁殖季普遍的筑巢失败是否会对繁殖期产生选择作用，导致种群后代提前产卵。

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.