LTREB: Long-term Studies of Demography and Social Behavior in a Colonial Bird

这项提案寻求对内布拉斯加州西南部悬崖燕子的人口学和社会行为的长期研究的20-24年的支持。调查人员将继续监测标记鸟类的生存、分散和群体选择，目前标记鸟类的数量为110,286只。这些数据将被用于其他正在进行的燕子种群生物学研究，其中将包括对种群规模影响的研究，并将被用于研究1996年在研究区域发生的一次罕见气候事件的长期人口统计学后果。在过去的125年里，这种时机和强度的恶劣天气只在内布拉斯加州西南部发生过两次，它使悬崖燕子的数量减少了50%以上。通过采用1982年以来开发和使用的相同方法和群体抽样计划，这项研究将提供跨越20多年的不同年份之间的直接比较。收集的数据将用于以下工作：(1)形态进化--对个体大小的定向选择，以及对罕见气候事件带来的低水平双边不对称的选择；(2)群体大小、类固醇激素水平和免疫能力之间的关系--繁殖季节不同时间的睾酮和皮质酮水平如何随群体大小变化；(3)体外寄生虫及其相关甲型病毒的传播动态；以及(4)群体大小的变化。

0075199BrownThis proposal seeks support for years 20-24 of a long-term study of demography and social behavior of cliff swallows in southwestern Nebraska. The investigators will continue to monitor survival, dispersal, and colony choice for a population of marked birds that now numbers 110,286 individuals. These data will be applied to other ongoing investigations of swallow population biology that will incorporate study of the effect of group size, and will also be used to study the long-term demographic consequences of a rare climatic event that occurred in the study area in 1996. Severe weather of this timing and magnitude has occurred in southwestern Nebraska only twice inn the last 125 years, and it reduced the population of cliff swallows by over 50%. By applying the same methods and colony sampling schemes developed and used since 1982, this study will provide direct comparisons among years during a period spanning over two decades. Data gathered will be applied to work on (1) morphological evolution - directional selection on body size and selection for low levels of bilateral asymmetry brought about by the rare climatic event; (2) the relationship between colony size, steroid hormone levels, and immunocompetence - how levels of testosterone and corticosterone at different times during the breeding season vary with colony size; (3) transmission dynamics of ectoparasites and their associated alphaviruses; and (4) variation in colony size.