Shedding light on nocturnal behaviour: a cost-effective solution for remote, infrared video recording in the field

For behavioural ecologists who study nocturnal animals, recording behaviour at night is essential but expensive. Added difficulties arise when filming minifauna, as the most popular methods of recording nocturnal behaviour (i.e. trail cameras) function at a minimum focal distance of 3 m or greater. Infrared (IR)-sensitive camcorders can provide excellent footage of smaller animals at a shorter distance but can cost over $1000 USD. In addition, these pricey cameras rarely stand up to the elements in the field and are also limited by short battery life. Here, we provide a field-tested method to record nocturnal behaviour, of both small and large animals, at a fraction of the cost. We have had great success modifying inexpensive, commercially available action cameras (GoPro Hero4 camcorders) to be IR sensitive, powering these units with cellular phone power banks and continuously recording behaviour overnight while using an array of a dozen cameras. In total, all components of a recording kit are available for under $150 USD at the time of this writing (February 2024) and can be easily assembled using the guidelines described in the present paper. This paper provides researchers with an economical strategy to record continuous behaviour in nocturnally active animals, with a kit that outperforms most currently available camera options across various contexts. While the proposed kit may provide the greatest benefits to researchers studying minifauna, the recording set-up can be easily and cheaply adapted to capture nocturnal megafauna behaviour. As such, we hope these methods increase the accessibility of science and expand the experimental toolkits of biologists interested in the fascinating, but much understudied, world of nocturnal animal behaviour.