Data from: Shared origins of 6 songbird species occurring as vagrants in California

This dataset contains stable hydrogen isotope measurements, geographic origin probability surfaces, and simulated origin distributions for 155 vagrant wood-warbler (Parulidae) specimens collected in California during fall migration. Six species were analyzed: Blackpoll Warbler, Magnolia Warbler, Chestnut-sided Warbler, Blackburnian Warbler, Palm Warbler, and Tennessee Warbler. Using feather δ²H values, we generated individual-level geographic origin probability surfaces masked to species breeding ranges using eBird Status and Trends. We conducted simulations weighted by breeding abundance to test whether vagrant origins could be explained by abundance patterns. Results demonstrate that vagrant individuals of all six species most likely originated from the western portions of their breeding ranges, not areas of greatest abundance, with five species showing geographic overlap in probable origins. The dataset includes raw isotope measurements, processed probability surfaces (n=155 GeoTIFF rasters), species-level simulated origin distributions using both eBird Status and Trends and Boreal Avian Modelling Project abundance data, breeding range shapefiles, and all code for reproducibility. These data support the hypothesis that common mechanisms underlie wood-warbler vagrancy to California and provide a framework for studying vagrancy in other migratory systems. This dataset supports the following publication: Heiser ER, Farnsworth A, Tietz J, Iliff MJ, Van Doren BM. 2025. Shared origins of 6 songbird species occurring as vagrants in California. Ornithology ukaf057. doi: https://doi.org/10.1093/ornithology/ukaf057本数据集包含155份秋季迁徙期间于加利福尼亚州采集的迷鸟森莺科（Parulidae）标本的稳定氢同位素测定值、地理起源概率面及模拟起源分布。本次研究分析了6个物种：黑顶森莺（Blackpoll Warbler）、木兰森莺（Magnolia Warbler）、栗胁森莺（Chestnut-sided Warbler）、黑胸橙喉森莺（Blackburnian Warbler）、棕榈森莺（Palm Warbler）和田纳西森莺（Tennessee Warbler）。 研究人员基于羽毛δ²H值，借助eBird现状与趋势（eBird Status and Trends）项目的数据，生成了以物种繁殖范围为掩膜的个体级地理起源概率面。本研究以繁殖丰度为权重开展模拟实验，以验证迷鸟的起源是否可通过丰度模式进行解释。 结果显示，6个物种的迷鸟个体最有可能起源于其繁殖范围的西部区域，而非丰度最高的区域，其中5个物种的推测起源存在地理重叠。本数据集包含原始同位素测定值、已处理的概率面数据（共155份GeoTIFF栅格）、基于eBird现状与趋势及北方鸟类建模项目（Boreal Avian Modelling Project）丰度数据生成的物种级模拟起源分布、繁殖范围形状文件（shapefile），以及用于实现可重复性的全部代码。 这些数据支持"森莺科鸟类迷迁至加利福尼亚州存在共同机制"的假说，并为研究其他迁徙系统中的迷鸟行为提供了分析框架。 本数据集关联的已发表文献如下： Heiser ER, Farnsworth A, Tietz J, Iliff MJ, Van Doren BM. 2025. 加利福尼亚州迷访鸣禽6个物种的共同起源. Ornithology ukaf057. DOI: https://doi.org/10.1093/ornithology/ukaf057