All birds sleep and many do so in a specific location, the roost. Thus, every day each individual needs to decide when to go to (enter) and leave the roosting place. This determines the timing of activity, a trait shaped by both natural and sexual selection. Despite its importance in a variety of contexts, including foraging, predation, mating success and parental care, variation in the timing of activity has rarely been studied. Here, we describe this variation in a population of Eurasian Blue Tits Cyanistes caeruleus roosting in nestboxes using data collected over 7 years. We investigate seasonal changes in the start and end of activity and assess to what extent these parameters are sex‐ and age‐specific and affected by weather. We show that the start of activity is relatively constant in relation to sunrise during winter but undergoes drastic changes during the breeding season. The end of activity is markedly later relative to sunset in mid‐winter and is also strongly influenced by breeding behaviour. Females generally start their activity later and end it earlier than males. The duration of daily activity is shorter during periods of rain and longer when temperatures are relatively high for the time of year.

中文翻译：

---

季节，性别，年龄和天气对欧亚蓝雀蓝藻活动时间中种群水平变异的影响

所有的鸟类都在睡觉，许多鸟类在特定的位置（栖息地）睡觉。因此，每个人每天都需要决定何时进入（进入）并离开栖息地。这决定了活动的时机，这是自然选择和性选择共同塑造的特征。尽管它在觅食，掠食，交配成功和父母照料等各种情况下都很重要，但很少研究活动时间的变化。在这里，我们描述了欧亚蓝雀Cyanistes caeruleus种群中的这种变异使用7年以上收集的数据在巢箱中栖息。我们调查活动开始和结束时的季节变化，并评估这些参数在多大程度上针对性别和年龄，并受天气影响。我们表明，活动的开始相对于冬季的日出而言是相对恒定的，但在繁殖季节会发生剧烈变化。相对于冬季中旬的日落，活动的结束时间明显晚一些，并且也受繁殖行为的强烈影响。女性通常比男性晚开始活动并结束活动。雨天的日常活动时间较短，一年中气温相对较高时则较长。