Sleep is considered to be of crucial importance for performance and health, yet much of what we know about sleep is based on studies in a few mammalian model species under strictly controlled laboratory conditions. Data on sleep in different species under more natural conditions may yield new insights in the regulation and functions of sleep. We therefore performed a study with miniature electroencephalogram (EEG) data loggers in starlings under semi-natural conditions, group housed in a large outdoor enclosure with natural temperature and light. The birds showed a striking 5-h difference in the daily amount of non-rapid-eye-movement (NREM) sleep between winter and summer. This variation in the amount of NREM sleep was best explained by night length. Most sleep occurred during the night, but when summer nights became short, the animals displayed mid-day naps. The decay of NREM sleep spectral power in the slow-wave range (1.1-4.3 Hz) was steeper in the short nights than in the longer nights, which suggests that birds in summer have higher sleep pressure. Additionally, sleep was affected by moon phase, with 2 h of NREM sleep less during full moon. The starlings displayed very little rapid-eye-movement (REM) sleep, adding up to 1.3% of total sleep time. In conclusion, this study demonstrates a pronounced phenotypical flexibility in sleep in starlings under semi-natural conditions and shows that environmental factors have a major impact on the organization of sleep and wakefulness.

中文翻译：

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欧洲八哥的睡眠时间受夜长和月相的影响很大。

睡眠被认为对表现和健康至关重要，但我们对睡眠的了解大部分是基于在严格控制的实验室条件下对少数哺乳动物模型物种的研究。在更自然的条件下，不同物种的睡眠数据可能会对睡眠的调节和功能产生新的见解。因此，我们在半自然条件下用微型脑电图 (EEG) 数据记录器对八哥进行了一项研究，这些八哥被安置在具有自然温度和光线的大型室外围栏内。在冬季和夏季之间，这些鸟类在非快速眼动 (NREM) 睡眠的每日数量方面表现出惊人的 5 小时差异。NREM 睡眠量的这种变化最好用夜间长度来解释。大多数睡眠发生在夜间，但当夏夜变得短暂时，这些动物表现出午间小睡。NREM 睡眠频谱功率在慢波范围 (1.1-4.3 Hz) 中的衰减在短夜比在长夜更陡峭，这表明夏季鸟类具有更高的睡眠压力。此外，睡眠受月相影响，满月期间 NREM 睡眠时间减少 2 小时。椋鸟几乎没有快速眼动 (REM) 睡眠，占总睡眠时间的 1.3%。总之，这项研究表明，在半自然条件下椋鸟的睡眠具有明显的表型灵活性，并表明环境因素对睡眠和觉醒的组织有重大影响。这表明夏季的鸟类有更高的睡眠压力。此外，睡眠受月相影响，满月期间 NREM 睡眠时间减少 2 小时。椋鸟几乎没有快速眼动 (REM) 睡眠，占总睡眠时间的 1.3%。总之，这项研究表明，在半自然条件下椋鸟的睡眠具有明显的表型灵活性，并表明环境因素对睡眠和觉醒的组织有重大影响。这表明夏季的鸟类有更高的睡眠压力。此外，睡眠受月相影响，满月期间 NREM 睡眠时间减少 2 小时。椋鸟几乎没有快速眼动 (REM) 睡眠，占总睡眠时间的 1.3%。总之，这项研究表明，在半自然条件下椋鸟的睡眠具有明显的表型灵活性，并表明环境因素对睡眠和觉醒的组织有重大影响。