Data from: Winter GPS tagging reveals home ranges during the breeding season for a boreal-nesting migrant songbird, the Golden-crowned Sparrow

Determining space use for species is fundamental to understanding their ecology, and tracking animals can reveal insights into their spatial ecology on home ranges and territories. Recent technological advances have led to GPS-tracking devices light enough for birds as small as ~30 g, creating novel opportunities to remotely monitor fine-scale movements and space use for these smaller species. We tested whether miniaturized GPS tags can allow us to understand space use of migratory birds away from their capture sites and sought to understand both pre-breeding space use as well as territory and habitat use on the breeding grounds. We used GPS tags to characterize home ranges on the breeding grounds for a migratory songbird with limited available breeding information, the Golden-crowned Sparrow (Zonotrichia atricapilla). Using GPS points from 23 individuals across 26 tags (three birds tagged twice), we found home ranges in Alaska and British Columbia were on average 44.1 ha (95% kernel density estimate). In addition, estimates of territory sizes based on field observations (mean 2.1 ha, 95% minimum convex polygon [MCP]) were three times smaller than 95% MCPs created using GPS tags (mean 6.5 ha). Home ranges included a variety of land cover classes, with shrubland particularly dominant (64–100% of home range cover for all but one bird). Three birds tracked twice returned to the same breeding area each year, supporting high breeding site fidelity for this species. We found reverse spring migration for five birds that flew up to 154 km past breeding destinations before returning. GPS-tracking technology allowed for critical ecological insights into this migratory species that breeds in very remote locations.

确定物种的空间利用模式是理解其生态学特征的核心基础，而对动物进行追踪能够揭示其家域与领地范围内的空间生态学相关信息。近年来的技术进步催生了重量轻到可用于体重仅约30克的小型鸟类的GPS追踪设备，为远程监测这类小型物种的精细尺度移动与空间利用模式提供了全新契机。本研究验证了微型GPS标签能否帮助我们了解捕获地之外的迁徙鸟类的空间利用模式，并旨在阐明其繁殖前期的空间利用情况，以及繁殖地内的领地与栖息地利用模式。我们针对繁殖相关信息极为匮乏的迁徙鸣禽——金冠带鹀（Golden-crowned Sparrow, *Zonotrichia atricapilla*），利用GPS标签对其繁殖地的家域特征进行了表征。基于26个标签（其中3只个体被二次标记）获取的23只个体的GPS点位数据，我们发现阿拉斯加与不列颠哥伦比亚省的繁殖地家域平均面积为44.1公顷（95%核密度估计（kernel density estimate）值）。此外，基于野外观测估算的领地面积（平均2.1公顷，95%最小凸多边形（minimum convex polygon, MCP））仅为GPS标签生成的95%MCP估算值（平均6.5公顷）的三分之一。其家域涵盖多种土地覆盖类型，其中灌丛占比尤其突出（除1只个体外，其余所有个体的家域灌丛覆盖占比均达64%~100%）。两次被追踪的3只个体每年均返回同一繁殖区域，证实该物种具有极高的繁殖地恋巢性。我们还观测到5只个体存在逆向春季迁徙行为：它们先飞至超出繁殖目的地最远达154公里的区域，随后再折返至繁殖地。GPS追踪技术为这种繁殖于极偏远区域的迁徙物种提供了至关重要的生态学认知依据。