Timing programs in animal migrants have been selected to synchronize movements that coincide with predictable resources on the breeding and nonbreeding grounds. Migrants face potential temporal conflicts if their migration schedules benefit from synchrony to conflicting rhythms associated with annual biogeographical (circannual) cues, lunar (circalunar) cues, or individually-repeatable internal clocks. We repeat-tracked individuals of an avian lunaphilic species, Eastern Whip-poor-will (Antrostomus vociferus), for 2–3 successive autumn migrations to determine the influence of the lunar cycle, breeding location, and individual repeatability on migration timing. Almost all birds avoided departing for migration during a full moon, likely to take advantage of the bright moonlight to facilitate visual foraging and enhance pre-migration fattening. However, groups from two latitudinally-distant sampling areas adjusted their autumn departure timing differently relative to the timing of the September full moon, presumably due to differences in seasonal prey availability. Individual repeatability increased throughout autumn migration, suggesting that the factors responsible for shaping migration timing may differ for different migration stages. Our results, that lunar synchrony, local climate, and individual internal clocks appeared to account for much of the variation in migration timing in whip-poor-wills, underscore the value of measuring potentially interacting factors that shape migratory behavior at species, group, and individual levels. It remains unclear if, or how, maintaining individually-repeatable annual migration schedules provides an adaptive benefit for whip-poor-wills or other lunaphilic migrants. Further clarifying the reasons for phenotypic variation in whip-poor-will migration timing will improve predictions of their abilities to adjust migratory movements under changing environmental conditions.

中文翻译：

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月球同步、地理和个体时钟影响鸟类秋季迁徙时间

动物迁徙的计时计划已被选择，以同步与繁殖地和非繁殖地的可预测资源相一致的运动。如果移民的迁徙时间表受益于与年度生物地理（圆周）线索、月球（圆周）线索或个人可重复的内部时钟相关的同步性或冲突节奏，那么移民就会面临潜在的时间冲突。我们对嗜月鸟类东部鞭穷人（Antrostomus vociferus）的个体进行了连续 2-3 次秋季迁徙的重复跟踪，以确定月球周期、繁殖地点和个体可重复性对迁徙时间的影响。几乎所有鸟类都避免在满月期间出发迁徙，很可能利用明亮的月光来促进视觉觅食并增强迁徙前的育肥能力。然而，来自两个纬度较远的采样区域的群体相对于九月满月的时间调整了不同的秋季出发时间，这可能是由于季节性猎物可用性的差异。在整个秋季迁徙过程中，个体的重复性有所增加，这表明影响迁徙时间的因素可能因不同的迁徙阶段而异。我们的研究结果表明，月球同步、当地气候和个体生物钟似乎在很大程度上解释了穷人的迁徙时间的变化，强调了测量影响物种、群体和群体迁徙行为的潜在相互作用因素的价值。个人水平。目前尚不清楚维持个人重复的年度迁徙时间表是否或如何为穷游者或其他狂热的迁徙者提供适应性好处。进一步阐明鞭穷人迁徙时间表型变异的原因将改善对其在不断变化的环境条件下调整迁徙运动的能力的预测。