Data from: Identifying the African wintering grounds of hybrid flycatchers using a multi–isotope (δ2H, δ13C, δ15N) assignment approach

<b>Abstract</b><br/>Migratory routes and wintering grounds can have important fitness consequences, which can lead to divergent selection on populations or taxa differing in their migratory itinerary. Collared (Ficedula albicollis) and pied (F. hypoleuca) flycatchers breeding in Europe and wintering in different sub-Saharan regions have distinct migratory routes on the eastern and western sides of the Sahara desert, respectively. In an earlier paper, we showed that hybrids of the two species did not incur reduced winter survival, which would be expected if their migration strategy had been a mix of the parent species’ strategies potentially resulting in an intermediate route crossing the Sahara desert to different wintering grounds. Previously, we compared isotope ratios and found no significant difference in stable-nitrogen isotope ratios (δ15N) in winter-grown feathers between the parental species and hybrids, but stable-carbon isotope ratios (δ13C) in hybrids significantly clustered only with those of pied flycatchers. We followed up on these findings and additionally analyzed the same feathers for stable-hydrogen isotope ratios (δ2H) and conducted spatially explicit multi-isotope assignment analyses. The assignment results overlapped with presumed wintering ranges of the two species, highlighting the efficacy of the method. In contrast to earlier findings, hybrids clustered with both parental species, though most strongly with pied flycatcher.

<b>摘要</b><br/>迁徙路线与越冬地可对物种适合度产生重要影响，进而对具有不同迁徙行程的种群或类群产生歧化选择。在欧洲繁殖、越冬于撒哈拉以南非洲不同区域的领姬鹟（Collared flycatcher, *Ficedula albicollis*）与斑姬鹟（pied flycatcher, *F. hypoleuca*），分别沿撒哈拉沙漠东西两侧拥有独特的迁徙路线。此前我们的研究表明，两个物种的杂交后代并未出现越冬存活率降低的情况；而若其迁徙策略为亲本策略的混合，进而通过穿越撒哈拉沙漠的中间路线抵达不同越冬地，则杂交后代越冬存活率下降本应是预期的结果。既往研究中，我们对比了羽毛同位素比值，发现亲本物种与杂交个体冬季生长羽毛中的稳定氮同位素比值（stable-nitrogen isotope ratios, δ¹⁵N）无显著差异，但杂交个体的稳定碳同位素比值（stable-carbon isotope ratios, δ¹³C）仅显著聚集于斑姬鹟的同位素分布范围内。针对上述发现，我们对同一批羽毛开展了稳定氢同位素比值（stable-hydrogen isotope ratios, δ²H）分析，并实施了空间显式多同位素归属分析。归属分析结果与两个物种的推测越冬范围相吻合，验证了该方法的有效性。与此前的研究结果不同的是，本次杂交个体的同位素信号同时聚集于两个亲本物种的范围内，不过与斑姬鹟的聚集程度更高。