Data from: Effect of fuel deposition rate on departure fuel load of migratory songbirds during spring stopover along the northern coast of the Gulf of Mexico

Migrants are generally assumed to minimize their overall migration time by adjusting their departure fuel loads (DFL) in relation to anticipated and experienced fuel deposition rates (FDRs). We utilized a 21-yr long migration banding station dataset to examine the relationship between FDR and DFL during spring migration in six Nearctic-Neotropical migratory songbird species during stopover along the northern coast of the Gulf of Mexico (GOM) following trans-gulf flight. Estimates of fuel stores, stopover durations, and FDRs from our long term migration data set were combined to determine DFL. We expected and found that migrants across all six species adjust their DFL to the rate at which they deposit fuel reserves. This robust finding suggests that songbird migrants are sensitive to time constraints during spring passage presumably to fine-tune their stopover schedule in relation to experienced and anticipated habitat quality. Two of the species studied showed an effect of age on the FDR–DFL relationship: one was consistent with the expectation that older birds would be less sensitive to changes in FDR, while the second was contrary to our expectations and likely suggesting an age-dependent response to habitat quality. We found sex-dependent differences consistent with male DFL being more sensitive to FDR in only two of six species studied, and argue that both males and females are time constrained during spring passage in relation to arrival at breeding destinations. The positive relationship between FDR and DFL among all species and for age and sex groups in some species reflects a migration strategy sensitive to time.学界普遍认为，迁徙鸟类会通过调整起飞燃料负载（Departure Fuel Loads, DFL），结合预期与实测的燃料沉积速率（Fuel Deposition Rates, FDR），尽可能压缩整体迁徙耗时。本研究依托一处运行21年的迁徙环志站数据集，针对6种新北区-新热带区迁徙鸣禽的春季迁徙行为展开分析：这些鸟类在完成跨墨西哥湾飞行后，于墨西哥湾（Gulf of Mexico, GOM）北岸停留休整，借此探究其FDR与DFL之间的关联。研究整合了长期迁徙数据集内的燃料储备、停留时长以及FDR估算值，以此推算得到DFL。我们最初预期且最终证实，6个物种的迁徙鸟类均会依据自身燃料储备的沉积速率调整DFL。这一稳健的研究结果表明，春季迁徙途中的鸣禽对时间约束较为敏感，推测其目的是结合实际与预期的栖息地质量，微调停留计划。其中2个研究物种的年龄因素会对FDR与DFL的关联产生影响：其一符合我们的预期——成鸟对FDR变化的敏感性更低；其二则与我们的预期相悖，该结果大概率反映了鸟类对栖息地质量存在年龄依赖的响应策略。在6个研究物种中，仅2个物种呈现出性别差异：雄性的DFL对FDR的敏感性更高。我们认为，春季迁徙期间雌雄个体均面临抵达繁殖目的地的时间约束。所有物种的FDR与DFL之间均存在正相关关系，部分物种的年龄、性别分组也呈现出该特征，这反映出迁徙鸟类的迁徙策略对时间约束较为敏感。