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

[00:75 . 90]本提案寻求对内布拉斯加州西南部崖燕的人口和社会行为进行20-24年的长期研究的支持。调查人员将继续监测有标记的鸟类种群的生存、分布和群体选择，这些鸟类现在有110,286只。这些数据将应用于其他正在进行的燕子种群生物学调查，其中将包括研究群体规模的影响，并将用于研究1996年在研究地区发生的罕见气候事件的长期人口后果。在过去的125年里，这种时间和规模的恶劣天气在内布拉斯加州西南部只发生过两次，它使崖燕的数量减少了50%以上。通过采用自1982年以来开发和使用的相同方法和群体抽样方案，本研究将在20多年的时间内提供年份之间的直接比较。收集到的数据将用于(1)形态进化——体型的定向选择和罕见气候事件带来的低水平双侧不对称的选择；(2)群体大小、类固醇激素水平与免疫能力的关系——繁殖季节不同时期睾酮和皮质酮水平随群体大小的变化规律；(3)体外寄生虫及其相关甲病毒的传播动态；(4)菌落大小的变化。

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.