Seasonal carry-over effects and connectivity inmigratory songbirds

每年秋天，数十亿只鸣禽在温带和热带之间迁徙，但关于繁殖或越冬事件如何影响迁徙的时间和速度，反之亦然，或者迁徙策略的个体差异对健康的影响，人们知之甚少。我率先在候鸟身上使用了轻量级地理定位器。地理定位器是档案标签(&lt；1.5G)，在迁移后检索时可用于推断迁移路线和时间。自2007年以来，我一直在林画眉和紫貂上使用地理定位器，并记录了在相同种群中繁殖的个体在迁徙路线、时间和速度方面的广泛差异。我将使用这项创新技术来测试(1)繁殖努力和时机如何影响秋季迁徙、换羽-迁徙重叠和随后的存活，(2)到达日期如何影响冬季栖息地的质量、生存、冬季身体状况和随后的春季迁徙，以及(3)繁殖和越冬地点之间的连接模式如何与种群下降联系在一起。为了观察遗传效应，研究人员将操控窝卵大小和繁殖时机，以检验父母努力程度高会延迟迁徙的预测。我还将操纵寄生虫的负载来测试血蛋白血液寄生虫感染会减缓秋季迁徙的预测。我将在越冬鸣鸟身上部署地理定位器，以测试秋季迁徙策略如何影响随后的领土质量、所有权和越冬生存。对冬季栖息地质量的试验性操纵(“升级”到更好的栖息地，补充食物)将检验这样一种预测，即质量差的栖息地推迟春季迁徙，从而到达繁殖地。据预测，连通性模式将影响繁殖地的种群下降，因为扩散连通性将一个地区冬季存活率低的影响扩散到大量繁殖种群。地球定位器将部署在多个繁殖和越冬种群的林画眉和紫貂身上，以绘制连接模式，并测试连接的强度是否可以预测区域繁殖种群的趋势。

Each fall billions of songbirds migrate between the temperate zone and tropics but little is known about how breeding or wintering events affect the timing and pace of migration, and vice versa, or the fitness consequences of individual differences in migration strategy. I have pioneered the use of light level geolocators on migratory songbirds. Geolocators are archival tags (< 1.5g) that when retrieved after migration can be used to infer migration routes and timing. I have used geolocators on Wood Thrush and Purple Martins since 2007 and have documented extensive variation in migration route, timing, and speed for individuals breeding in the same population. I will use this innovative technology to test (1) how reproductive effort and timing affects fall migration, moult-migration overlap and subsequent survival, (2) how arrival date affects winter territory quality, survival, winter body condition and subsequent spring migration, and (3) how connectivity patterns between breeding and wintering sites are linked to population declines. To look at carry-over effects, clutch size and timing of breeding will be manipulated to test the prediction that high parental effort delays migration. I will also manipulate parasite loads to test the prediction that infection by Haemoproteus blood parasites slows fall migration. I will deploy geolocators on wintering songbirds to test how fall migration strategy affects subsequent territory quality, ownership, and over-winter survival. Experimental manipulation of winter territory quality ("upgrading" to a better territory, food supplementation) will test the prediction that poor quality territory delays spring migration and thus arrival on the breeding territory. Connectivity patterns are predicted to affect population decline on the breeding grounds because diffuse connectivity spreads the impact of low winter survival in a region over a large number of breeding populations. Geolocators will be deployed on multiple breeding and wintering populations of Wood Thrushes and Purple Martins to map connectivity patterns and test if the strength of connectivity predicts regional breeding population trends.