1. Bats represent a highly diverse group of mammals and are essential for ecosystem functioning. However, knowledge about their behaviour, ecology and conservation status is limited. Direct observation of marked individuals (commonly applied to birds) is not possible for bats due to their small size, rapid movement and nocturnal lifestyle, while neither popular observation methods such as camera traps nor conventional tracking technologies sufficiently capture the behaviour of individuals. The combination and networking of different sensors in a single system can overcome these limitations, but this potential has been explored only to a limited extent.
2. We present BatRack, a multi-sensor device that combines ultrasonic audio recordings, automatic radio telemetry and video camera recordings in a single modular unit. BatRack facilitates the individual or combined scheduling of sensors and includes a mutual triggering mode. It consists of off-the-shelf hardware and both its hardware blueprints and the required software have been published under an open license to allow scientists and practitioners to replicate the system.
3. We tested the suitability of radio telemetry and audio sensors as camera triggers and evaluated the detection of individuals in video recordings compared to radio telemetry signals. Specifically, BatRack was used to monitor the individual swarming behaviour of six members of a maternity colony of Bechstein's bat. Preliminary anecdotal results indicate that swarming intensity is related to reproductive state and roost switching.
4. BatRack allows researchers to recognize individual bats and monitor their behavioural patterns using an easily deployed and scalable system. BatRack is thus a promising approach to obtaining detailed insights into the behavioural ecology of bats.

中文翻译：

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BatRack：用于野生动物研究的开源多传感器设备

1. 蝙蝠代表了高度多样化的哺乳动物群体，对生态系统功能至关重要。然而，关于它们的行为、生态和保护状况的知识是有限的。蝙蝠由于体型小、运动迅速和夜间生活方式，无法直接观察标记个体（通常适用于鸟类），而流行的观察方法（如相机陷阱）和传统的跟踪技术都无法充分捕捉个体的行为。单个系统中不同传感器的组合和联网可以克服这些限制，但这种潜力仅在有限的程度上得到了探索。
2. 我们展示了 BatRack，这是一种多传感器设备，将超声波录音、自动无线电遥测和摄像机记录结合在一个模块化单元中。BatRack 有助于传感器的单独或组合调度，并包括相互触发模式。它由现成的硬件组成，其硬件蓝图和所需的软件已在开放许可下发布，以允许科学家和从业人员复制该系统。
3. 我们测试了无线电遥测和音频传感器作为相机触发器的适用性，并评估了与无线电遥测信号相比视频记录中个人的检测。具体而言，BatRack 用于监测 Bechstein 蝙蝠母性群体 6 名成员的个体蜂群行为。初步的轶事结果表明，蜂群强度与繁殖状态和栖息地转换有关。
4. BatRack 允许研究人员使用易于部署和可扩展的系统识别单个蝙蝠并监控它们的行为模式。因此，BatRack 是一种获得对蝙蝠行为生态学的详细见解的有前途的方法。