BoomBox: An Automated Behavioural Response (ABR) camera trap module for wildlife playback experiments

Abstract

Camera traps (CTs) are a valuable tool in ecological research, amassing large quantities of information on the behaviour of diverse wildlife communities. CTs are predominantly used as passive data loggers to gather observational data for correlational analyses. Integrating CTs into experimental studies, however, can enable rigorous testing of key hypotheses in animal behaviour and conservation biology that are otherwise difficult or impossible to evaluate. We developed the 'BoomBox', an open‐source Arduino‐compatible board that attaches to commercially available CTs to form an Automated Behavioural Response (ABR) system. The modular unit connects directly to the CT’s passive infrared (PIR) motion sensor, playing audio files over external speakers when the sensor is triggered. This creates a remote playback system that captures animal responses to specific cues, combining the benefits of camera trapping (e.g. continuous monitoring in remote locations, lack of human observers, large data volume) with the power of experimental manipulations (e.g. controlled perturbations for strong mechanistic inference). Our system builds on previous ABR designs to provide a cheap (~100USD) and customizable field tool. We provide a practical guide detailing how to build and operate the BoomBox ABR system with suggestions for potential experimental designs that address a variety of questions in wildlife ecology. As proof‐of‐concept, we successfully field tested the BoomBox in two distinct field settings to study species interactions (predator–prey and predator–predator) and wildlife responses to conservation interventions. This new tool allows researchers to conduct a unique suite of manipulative experiments on free‐living species in complex environments, enhancing the ability to identify mechanistic drivers of species' behaviours and interactions in natural systems.

Frightened of giants: fear responses to elephants approach that of predators

“…To understand the fear response of ungulates to elephants, we used ABRs to play recordings of three vocalizations: elephants, leopards and procedural controls [ 20 , 22 , 26 ]. The leopard is the primary apex predator in our study area and has previously been shown to induce the greatest fear responses from ungulates in this area [ 22 ].…”

“…To determine if megaherbivores can induce fear in other mammals, we contrasted the behavioural responses of medium- to large-sized ungulates to cues of a megaherbivore, the African bush elephant ( Loxodonta africana ), relative to a common predator, the leopard ( Panthera pardus ), in an African savannah. To isolate behavioural responses, we used an automated behavioural response (ABR) system comprised of a motion-activated camera and speaker [ 20 ]. This ABR system allowed quantification of reactive responses (as opposed to proactive responses [ 21 ]) of ungulates to different cues.…”

Incorporating animal agency into research design could improve behavioral and neuroscience research.

“…Some automatic devices already exist to make some playback experiments as BoomBox: an automated behavioral response (ABR) camera trap module for wildlife experiments (Palmer et al, 2022). Food containers of various kinds have been used in field experiments (De la Fuente et al, 2022; Van de Waal et al, 2013), and robots are increasingly used with wild animals (Grémillet et al, 2012; Le Maho et al, 2014).…”

Low-cost automated call box system to conduct playback experiments for wildlife research and management

“…[2e.g. [22] , [23] , [24] ). The broadcast by motor sensor limits functionality to test certain questions related to the social information hypothesis, such as habitat selection (for breeding, winter, or stopover habitats), mating choices, and/or triggering fright responses.…”