Different snake species may be active at various times of the day. In Europe, most snake species are predominantly diurnal, but about a third are partially or principally crepuscular and/or nocturnal. Here, we report the first instance of multiple in situ observations of the crepuscular and nocturnal activity of V. ammodytes in Bulgaria. Overall, usually as a result of general herpetological surveys and chance observations between 2001–2020, we recorded crepuscular/nocturnal activity of twenty-seven individuals from both sexes and all age classes (juvenile to adult), observed from April to September, following warm (maximum daily Tair = 20–28 °C) and hot (Tair > 28 °C) days. These records represent less than 1.5% of all our personal viper observations. However, given that our observations occurred throughout the country, within five different climatic zones, we hypothesise that nocturnal activity of V. ammodytes is more common than previously reported.

中文翻译：

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鼻角vi蛇的mm蛇和夜间活动比Vi蛇更常见（Linnaeus，1758年）

不同的蛇种可能在一天的不同时间活跃。在欧洲，大多数蛇种主要是昼夜的，但约有三分之一是部分或主要是晚上和/或夜间的。在这里，我们报告保加利亚原虫的夜蛾活动和夜活动的多个原位观察的首次实例。总体而言，通常是2001年至2020年间进行的总体爬虫学调查和偶然观察的结果，我们记录了从4月至9月观察到的47例男女性别和所有年龄段（青少年至成人）的夜间/夜间活动， （每天的最大Tair = 20–28°C）和炎热的（Tair> 28°C）天。这些记录不到我们所有个人毒蛇观察的1.5％。但是，鉴于我们的观察发生在全国各地，