Understanding spatial and temporal movement patterns of migratory birds throughout the annual cycle can help identify potential population threats. The behavior and habitat use of birds during migration and stopover periods is particularly understudied in many species. In this study, we used high spatial resolution archival GPS tags to track Rusty Blackbirds (Euphagus carolinus) from one eastern (New Hampshire) and two western (Alaska and Alberta) breeding populations across the annual cycle. We sought to determine: 1) migratory connectivity of the three distinct populations; 2) migratory phenology, behavior, and time spent during each phase of the annual cycle; and 3) habitat use of individuals throughout the nonbreeding period. We retrieved 7 tags from 30 tagged individuals following 1-year deployments. We found that four Alberta individuals overwintered in the Mississippi Alluvial Valley, two Alaska individuals overwintered in either the Great Plains or the Mississippi Alluvial Valley, and the single New Hampshire individual overwintered on the Southeastern Coastal Plain. Length of annual cycle stages varied among individuals, with the combined migratory periods occupying between 12% and 48% of the annual cycle. Stopover behavior was also widely variable, as minimum convex polygons of stopovers ranged from < 1 hectare to 505 km² and stopover durations ranged from 1 to 35 days (n = 40 stopovers). Birds predominantly used woody wetlands and emergent marsh during the nonbreeding period, but habitat use differed between roosting and foraging. Marshes were used more for nocturnal roosting, whereas woody wetlands were used for diurnal foraging. Our results can help efforts to conserve this declining species by targeting regions and habitats at specific times of year for management during the nonbreeding period. In particular, the large amount of time spent during migration periods suggests conservation efforts in stopover regions are just as important as those on the wintering grounds.

中文翻译：

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通过档案 GPS 标签揭示了生锈黑鸟（Euphagus carolinus）的迁徙连通性和年度周期物候学

了解候鸟在整个年度周期中的空间和时间运动模式有助于识别潜在的种群威胁。在许多物种中，鸟类在迁徙和中途停留期间的行为和栖息地利用尤其缺乏研究。在这项研究中，我们使用高空间分辨率档案 GPS 标签来跟踪来自一个东部（新罕布什尔州）和两个西部（阿拉斯加和艾伯塔省）繁殖种群的生锈黑鸟 (Euphagus carolinus) 整个年度周期。我们试图确定：1）三个不同种群的迁移连通性；2) 迁徙物候、行为和在年度周期的每个阶段花费的时间；3) 个体在整个非繁殖期的栖息地利用。经过 1 年的部署，我们从 30 个标记的个人中检索了 7 个标记。我们发现四个艾伯塔个体在密西西比冲积谷过冬，两个阿拉斯加个体在大平原或密西西比冲积谷过冬，一个新罕布什尔个体在东南沿海平原过冬。年循环阶段的长度因人而异，综合迁徙期占年循环的 12% 至 48%。中途停留行为也有很大差异，因为中途停留的最小凸多边形范围从 < 1 公顷到 505 平方公里不等，中途停留时间范围为 1 到 35 天（n = 40 次中途停留）。在非繁殖期，鸟类主要使用木质湿地和挺水沼泽，但栖息地和觅食的栖息地使用不同。沼泽更多地用于夜间栖息，而木质湿地则用于昼夜觅食。我们的结果可以通过在一年中的特定时间针对区域和栖息地进行非繁殖期间的管理来帮助保护这种正在下降的物种。特别是，在迁徙期间花费的大量时间表明，中途停留地区的保护工作与越冬地的保护工作同样重要。