Data from: Sex-specific, inverted rhythms of breeding-site attendance in an Arctic seabird

In contrast to daily rhythms that are common in the presence of the geophysical light–dark cycle, organisms at polar latitudes exhibit many diel activity patterns during natural periods of continuous solar light or darkness (polar day and night, respectively), from 24 h rhythms to arrhythmicity. In Arctic Greenland (73.7° N, 56.6° W) during polar day, we observed breeding-site attendance rhythms of thick-billed murres (Uria lomvia; n = 21 pairs), a charadriiform seabird, which provide biparental care at the colony. We found that U. lomvia egg-incubation and chick-brooding attendance is rhythmic and synchronized to the geophysical day (mean period length [rhythm duration] ± 95% confidence interval = 24.13 ± 0.52 h). Individual pair members had temporally segregated, sex-specific colony-attendance rhythms that were opposite (inverted) to each other, and these sex-specific rhythms were prominent at the population level. Our results provide a basis for investigating circadian systems at polar latitudes and sex-specific parental-care strategies.

与地球物理明暗周期下常见的日常节律不同，极地纬度地区的生物在持续日照或持续黑暗的自然周期（分别对应极地昼与极地夜）中，会表现出多种昼夜活动模式，覆盖24小时节律至无节律的多种状态。本研究在北极格陵兰地区（北纬73.7°，西经56.6°）的极地昼期间，对鸻形目海鸟厚嘴海鸦（Uria lomvia，共21对繁殖对）的繁殖领地出勤节律开展观测，该鸟类在繁殖群落中实行双亲育幼策略。研究发现，厚嘴海鸦的卵孵化与雏鸟育雏出勤行为呈现节律性，且与地球物理日同步，其平均周期时长（节律持续时间）±95%置信区间为24.13±0.52小时。配对个体中的雌雄成员各自拥有时间上分离的性别特异性群落出勤节律，二者呈完全相反（反转）的模式，且这类性别特异性节律在种群层面表现显著。本研究结果为极地高纬度地区的昼夜节律系统研究以及性别特异性育幼策略探索提供了重要依据。