Migration theory has largely overlooked the role of overwintering grounds and yet many migratory animals spend most of the annual cycle there. High winter site familiarity could confer considerable advantages on animals preparing for subsequent migration phases, enabling them to maximize migration speed and minimise the use of unknown stopover sites. Despite this, quantitative studies of the magnitude of fuel stores attained at such sites are lacking. To evaluate the energetic contribution of an overwintering site to spring migration, we used manual and automated telemetry to estimate departure date, departure fuel load, flight range and breeding destination of blackpoll warblers (Setophaga striata) wintering in Colombia. Relative to overwinter mass, warblers increased body mass (a surrogate for fuel stores) by an average of 59% prior to departure from the overwintering site. Flight range (mean 2710 km, range 2110–3380 km, N = 16) and detections at automated telemetry stations in North America suggest movements to Cuba/southeastern US, before refuelling and then continuing towards breeding grounds in eastern Canada (total duration ∼ 30 days). Total migration length was ∼ 5350 km and energy acquired at the overwintering site was sufficient to cover 39–63% (mean = 50%), demonstrating the major contribution tropical wintering grounds can make to migration. It follows that varying the extent of fuelling prior to departing overwintering sites may provide animals with a mechanism for balancing their exposure to risk during migration, while simultaneously allowing for flexibility in migratory schedules in a changing world.

中文翻译：

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没有比家更合适的地方：热带越冬地可能在制定迁徙策略方面发挥重要作用

迁徙理论在很大程度上忽视了越冬地的作用，但许多迁徙动物一年中的大部分时间都在那里度过。对冬季站点的高度熟悉可以为准备后续迁移阶段的动物带来相当大的优势，使它们能够最大限度地提高迁移速度并最大限度地减少对未知中途停留站点的使用。尽管如此，缺乏对这些地点获得的燃料储存量的定量研究。为了评估越冬地点对春季迁徙的能量贡献，我们使用手动和自动遥测技术来估计黑鸟莺 (Setophaga striata) 在哥伦比亚越冬的出发日期、出发燃料负荷、飞行范围和繁殖目的地。相对于越冬质量，在离开越冬地点之前，莺的体重（燃料储存的替代品）平均增加了 59%。飞行范围（平均 2710 公里，范围 2110-3380 公里，N = 16）和在北美自动遥测站的检测表明，在加油之前向古巴/美国东南部移动，然后继续前往加拿大东部的繁殖地（总持续时间 ~ 30天）。总迁移长度约为 5350 公里，在越冬地点获得的能量足以覆盖 39-63%（平均值 = 50%），表明热带越冬地对迁移的主要贡献。因此，在离开越冬地之前改变加油的程度可能会为动物提供一种机制来平衡它们在迁徙过程中面临的风险，