Ecological studies often require observations of animals and their behaviour. Motion‐activated cameras (camera traps) based on passive infrared detection (PIR) are a popular solution for recording animal activity in situations when it is impractical for humans to make sufficient observations. However, the reliability of these cameras for recording smaller vertebrates remains uncertain. We assessed the reliability of two widely used PIR camera traps (Bushnell 119740 and Moultrie 13068) for detecting small vertebrates. Specifically, we tested the effects of (1) camera trap model, (2) camera–subject distance and (3) animal class and size on the probability of detection. Brown rats moving across the ground were detected by the Bushnell camera with >80% probability at camera–subject distances ranging from 60 cm to 2 m, while the Moultrie camera was less efficient at distances >1 m. The probability of the Bushnell camera detecting birds feeding on flowers decreased from c. 80% at distances of 40–60 cm to <10% at 2 m and beyond. Larger birds (>20 g) were more likely to be detected than smaller birds (<15 g). Close‐focusing lenses on the Bushnell camera readily allow identification of individual bird species. These results help to establish guidelines for camera trap selection and placement in ecological studies of small terrestrial mammals and birds.

中文翻译：

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运动触发的相机陷阱在生态研究中检测小型哺乳动物和鸟类的可靠性如何？

生态学研究通常需要观察动物及其行为。基于被动红外检测（PIR）的运动激活相机（相机陷阱）是一种在人类不愿进行足够观察的情况下记录动物活动的流行解决方案。但是，这些照相机记录较小脊椎动物的可靠性仍然不确定。我们评估了两个广泛使用的PIR相机陷阱（Bushnell 119740和Moultrie 13068）用于检测小脊椎动物的可靠性。具体来说，我们测试了（1）相机陷阱模型，（2）相机与对象之间的距离以及（3）动物类别和大小对检测概率的影响。Bushnell相机检测到在地面上移动的褐家鼠，其相机对象距离范围为60 cm至2 m，概率> 80％，而Moultrie相机在距离> 1 m时效率较低。Bushnell相机检测到以花为食的鸟类的概率从c。在40–60 cm的距离处为80％，在2 m及更高处小于<10％。较大的鸟类（> 20 g）比较小的鸟类（<15 g）更有可能被检测到。布什内尔相机上的近焦镜头可轻松识别单个鸟类。这些结果有助于为小型陆生哺乳动物和鸟类的生态研究建立照相机诱集装置选择和放置指南。